Amino acid-assisted carbon quantum dots for bioimaging, Picric acid detection, antibacterial activity, and prefabrication of Pd nanoparticles as a potent nanocatalyst for coupling reactions and reduction of nitrophenols

Amino acid-assisted carbon quantum dots for bioimaging, Picric acid detection, antibacterial activity, and prefabrication of Pd nanoparticles as a potent nanocatalyst for coupling reactions and reduction of nitrophenols | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Amino acid-assisted carbon quantum dots for bioimaging, Picric acid detection, antibacterial activity, and prefabrication of Pd nanoparticles as a potent nanocatalyst for coupling reactions and reduction of nitrophenols Namrata Priyadarshini Hota, Saluja Diksha, Nandhini Karthikeyan, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6170167/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract Using bottle gourd peel and arginine, the hydrothermal sustainable approach was employed to synthesize blue emissive nitrogen-doped carbon quantum dots (NCQD) with a quantum yield of 29.40%. The excitation-dependent action of NCQD led to its choice for the detection of picric acid (PA), bioimaging investigations for MCF-7 (breast cancer) cells, and as an antibacterial agent against Staphylococcus aureus and Klebsiella pneumonia bacteria. The limit of detection (LoD) for picric cid was discovered to be 10 nM. Palladium nanoparticles (Pd nanoparticles) were prepared from the synthesized NCQD, where the NCQD served as both a reducing and stabilizing agent for the Pd nanoparticles. Several spectroscopic methods were also used to analyze the nanoparticles. The wide surface area and small Pd nanoparticles make them an ideal catalyst for reducing nitrophenols in aqueous medium and denitrogenative cross-coupling reactions. Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 1. Introductions In past decades, Carbon quantum dots (CQDs) have transpired as a center of attraction ascribed to their low toxicity, greater quantum yield, luminescence, biocompatibility, high photostability, and ease of synthesis [ 1 ]. These CQDs are renowned for their applications like analyte sensing [ 2 ], bioimaging, catalysis [ 3 ], photocatalysis [ 4 ], gene delivery, and drug delivery [ 5 ], When the single-walled carbon nanotubes (SWCT) were being purified by Xu et. al., in 2004 they inadvertently discovered “Carbon quantum dots”. Then in 2006, Sun et al. effortlessly synthesized surface passivated emissive fluorescent carbon dots and coined the term ‘Carbon quantum dots’ [ 6 , 7 ]. These quasispherical nanocrystal CQDs are zero-dimensional, and the size is less than 10 nm [ 8 ]. On that account, several synthetic methodologies such as top-down and bottom-up approaches have been followed. chemical oxidation [ 9 ], plasma therapy [ 10 ], arc discharge [ 11 ], electrochemical exfoliation [ 12 ], and laser ablation [ 13 ] are top-down methods, that necessitate sophisticated machines and a large amount of energy, which are both time-consuming and costly. Bottom-up synthesis, on the other hand, is eco-friendly, cost-effective, and environmentally beneficial [ 14 ], making it a greener technique. The bottom-up techniques include microwave irradiation [ 15 ], solvothermal [ 16 ], hydrothermal [ 17 ], and pyrolysis [ 18 ]. Hydrothermal is the most sustainable way to create an eco-friendly, non-toxic fluorescent CQD among these bottom-up strategies. However, the CQD generated from sole biomass has a lower quantum yield (< 10%), but doping heteroatoms like nitrogen [ 19 , 20 ], sulfur [ 21 ], phosphorus [ 22 ], etc. would boost the quantum yield, which is popularly known as surface passivation [ 23 ]. As the CQD surfaces are covered up with diverse functional groups, heteroatom-doped CQD can be used as a sensor as well as a possible candidate for antibacterial [ 24 ] and antifungal drugs, bioimaging, and catalysis. The primary focus of current research is the detection of hazardous analytes, particularly from water. Heavy metals and toxic analytes are found in harmful substances from various sources, particularly industry, which harm surface and subsurface water, thereby endangering living beings [ 25 ]. Picric acid (PA), often referred to as 2,4,6 trinitrophenol (TPN), is a water-soluble and poisonous analyte that finds extensive application as a reagent in the dye, pharmaceutical, and synthetic chemical industries [ 26 ]. Lower concentrations of these TNPs can also result in several health problems, including cancer, lung damage, eye damage, and respiratory disorders [ 27 ]. M. K. Meheto et al. (2023) synthesized CQD from malic acid and urea in microwave-assisted pyrolysis method for picric acid detection [ 28 ], Arunkumar K. et. al. (2020) synthesized CQD from thiourea and citric acid in pyrolysis method for selectively detecting picric acid [ 29 ], in the hydrothermal method, Y. Wang et. al. (2018) synthesized CQD from ethylene diamine and mandelic acids for the detection of picric acid [ 30 ]. These quantum dots have well-established electron-withdrawing and donating potential. They have the adaptability to lend and receive electrons from the electron-lacking and electron-abundant groups [ 31 ]. The CQD’s surface covers a range of functional groups that could be responsible for synthesizing metal nanoparticles, where these CQDs function as reducing and supporting agents. These CQDs can be used for both sensing and bioimaging studies as well as the creation of metal nanoparticles. Apart from these, the metal nanoparticles possess tremendous applications in the catalysis field, hydrogen evolution [ 32 ], reduction of toxic nitrophenols [ 33 ], etc. The carbon-carbon (C-C) coupling reaction has always been the ultimate intriguing topic to investigate in Organic Chemistry. The biaryl compounds found in C-C coupling processes are used in a wide range of sectors, such as natural goods, plastics, and pharmaceuticals [ 34 ]. These compounds can be produced by palladium complexes with ligands (such as phosphine, imidazole, and N-heterocyclic carbenes) that function as catalysts [ 35 – 37 ]. Nevertheless, the synthesis of these chemicals is more labor-intensive and costly due to the palladium catalysts. To overcome these problems, these molecules can be synthesized using a variety of nanoparticles. Numerous methods exist for synthesizing palladium nanoparticles, including quantum dots [ 38 ] and green methods [ 39 ]. In this study, we show that nitrogen-doped carbon quantum dots can be made hydrothermally by combining arginine and bottle gourd peel. This NCQD functions as an antibacterial agent, a fluorophore for selectively detecting picric acid, and for bioimaging investigation of the MCF 7 (breast cancer cells) cell line. In the process of synthesizing palladium nanoparticles, the NCQD is also employed as a reducing and supporting agent. These palladium nanoparticles catalyze the reduction of nitrophenols and denitrogenative coupling. 2. Experimental 2.1 Materials The required solvents and chemicals were purchased from chemical retailers such as Sigma Aldrich, Avra, TCI, etc. The Hitachi (model 2910) instrument was used to investigate (ultra violet) UV-visible absorption studies. To investigate the fluorescence emission studies, a Hitachi (model F-7000) instrument was used. Surface area analysis was done by Quantachrome USA Model AutosorbiQ instruments. Powder-X-ray diffraction (P-XRD) was performed by Bruker, D8-Advance P-XRD instrument. JASCO 4100 spectrometer was used to record Fourier Transform Infrared (FTIR) data. To know the chemical structure of the synthesized molecules, proton Nuclear magnetic resonance (NMR) spectroscopy was used by using a Bruker Ascent 400 Hz spectrometer. To measure the chemical shift, CDCl 3 was used as solvent and TMS was used as internal standard. 2.2 Preparation of NCQD A sustainable hydrothermal technique was utilized to prepare the NCQD. Bottle gourd was used as the plant source while arginine was used as the nitrogen source. In a Teflon coated hydrothermal bomb, 1 g of bottle gourd peel and 200 mg of arginine were added, along with 50 ml of water. For six hours, the reaction mixture was held in a muffle furnace. The created NCQD was left outside overnight to reach room temperature. After that, the NCQD was centrifuged for 15 minutes at 4000 RPM to get rid of the residue. It was syringe-filtered and stored in the fridge. NCQD exhibited a strong blue fluorescence upon exposure to UV light. The NCQD was then applied to a variety of applications, including sensing, bioimaging, antimicrobial activity, and palladium nanoparticle production. 2.3 Fluorescent detection of Picric acid 1 mmol stock solutions were prepared for each analyte using double-distilled water, and it was subsequently diluted to a concentration of 100µM. A cuvette was filled with two milliliters of 50 times diluted NCQD, and the emission and excitation wavelengths were then recorded. To record the Fluorescence emission 300 nm was opted as the excitation wavelength. Then, 100 µL of each anion was combined with 2 ml of NCQD one at a time, and the fluorescence intensity was recorded. In contrast to all other analytes, picric acid was seen to exhibit a change in fluorescence intensity, indicating that this specific NCQD specifically senses picric acid. 2.4 Protocols for MTT Assay MTT stands for 3-[4,5-dimethylthiazol-2-yl] 2,5-diphenyltetrazolium bromide which is a yellow water-soluble tetrazolium salt. MCF7 breast cancer cell was collected from the National Centre for Cell Sciences (NCCS). The collected cell was cultivated in eagles Minimum Essential Medium with 10% fetal bovine serum. The cells were retained in 95% air, 5% CO 2 , 100% relative humidity, and at 37 o C. This MTT reacts with the mitochondrial enzyme in the living cells and letting them react with the living cells with an incubation period of 48h [ 40 ]. After the time duration, 15 µl of MTT (after maintaining the pH with phosphate saline buffer) was solubilized in 100 µl of DMSO and the absorbance was recorded at 570 nm using a microplate reader [ 41 ]. Procedure for bioimaging studies of NCQD The procedure involved seeding 5 x 10 5 MCF 7 cells/ml into a 24-well tissue culture plate, followed by treatment with 6 µg/ml of NCQD in DMEM media without the serum. The tissue cultured plate was nurtured for 24 hours at 37°C with 5% CO 2 . After the nurturing period, 50 µL each of ethidium bromide and acridine orange (1 mg/ml) were added to the wells and delicately mixed. Eventually, the plate was centrifuged at 800 rpm for 2 minutes and inspected within an hour. About 100 cells were perceived by using a fluorescence microscope and a fluorescent filter. 2.5 Procedure for antibacterial activities of NCQD After being pre-cultured in nutrient broth for an entire night at 37°C in a rotary shaker, the gram-positive bacteria Staphylococcus aureus and the gram-negative bacteria Klebsiella pneumonia were centrifuged for five minutes at 10,000 rpm, pelletized and the pellet was suspended in double distilled water, and the cell density was standardized spectrophotometrically (A610 nm). Using a sterile spatula, the conidia were scraped off the Petri dishes after adding 8 to 10 milliliters of distilled water. A spectrophotometer (A595nm) was used to regulate the spore density of each bacterium to reach a final concentration of roughly 105 spores/ml. 2.6 Synthesis of Pd nanoparticles NCQD was used in the preparation of Pd nanoparticles. When synthesizing Pd nanoparticles, the NCQD is used as a stabilizing and reducing agent. The protocol calls for adding 100 milliliters of 0.02M Pd (OAc) 2 to a round-bottom flask, sonicating it for five minutes, and then keeping it in an oil bath at 80 degrees Celsius while stirring it for a few more minutes. Subsequently, the solution was progressively mixed with 20 milliliters of NCQD and allowed to remain at that temperature for two hours. As can be seen, the color of the solution changed to black from light brown, signifying the creation of Pd nanoparticles as well as the reduction of Pd (II) to Pd (0) [ 33 ]. The solution was centrifuged multiple times with water, ethanol, and acetone to eliminate any undesired constituents from the synthesized nanoparticles when it reached room temperature and then stored for drying. After being dried and milled into a fine powder, the Pd nanoparticles were subsequently submitted for several types of characterizations. Furthermore, it is utilized as a catalyst for the reduction of nitrophenol and denitrogenative cross-coupling processes. 3. Results and discussion 3.1 Characterization and optical behavior of NCQD: Since the NCQD's surface is covered with a variety of functional groups, FTIR analysis was performed, and the results indicated that the spectrum had notable peaks for several of these functional groups Fig. 1 The strong band at 3344 cm -1 clearly demonstrates the asymmetric stretching of the -OH/NH bond [42]. Peaks at 2972 cm -1 and 2880 cm -1 are affiliated with -C-H groups; similarly, peaks at 1671, 1453, 1380, 1090, 1045, and 880 cm -1 are associated with amide C = O, alkane CH, phenol OH, amine C-N, anhydride C-O stretching, and alkene C = C. Moreover, both UV-visible and fluorescence spectra were recorded for studying optical characteristics (Fig. 2 (a)). The NCQD revealed a vivid blue colour under UV light, but to the unaided sight, they seemed yellow. One peak at 226 nm in the matching UV spectrum represents the π-π* transition brought on by C = C and C = N bonds, while the other two peaks at 275 and 350 nm are in charge of the n-π* transition brought on by C = O bonds. The NCQD exhibited a vivid blue emission at 450 nm after exiting at 290 nm, demonstrating its luminous nature. Additionally, these carbon dots exhibited excitation-dependent photoluminescence (PL), which might have been caused by flaws in the NCQD size and surface (Fig. 2 (b)). The quantum yield of the NCQD was found to be 29.40% using quinine sulfate as a reference. There was no appreciable change observed in the fluorescence spectra after irradiation for one hour at 290nm. Later, pH studies were taken into account, solutions with a pH range of 2 to 12 were made using 0.1M HCl and NaOH, and a pH meter was used to determine the necessary pH value. The study revealed that the FL intensity began to drop at pH 2 and continued to rise until it reached the neutral pH of 7. This pattern resulted from protonation brought on by functional groups such as (-OH, -NH) on the NCQD surface. The intensity was observed to drastically drop when the pH became basic ( Figure S1) . The fact that the maximum intensity was at neutral pH nevertheless shows how appropriate a neutral pH value is for the bioimaging and sensing investigations. 3.1.1 Selective detection of Picric acid The earlier synthesized NCQD was used as a highly selective fluorophore to detect picric acid. The interaction with NCQD was assessed using a range of competitive ions and acids, such as 2-nitrophenol (2-NP), 3- nitrophenol (3-NP), 4-nitrophenol (4-NP), dichloronitrobenzene (DCNB), difluoronitrobenzene (DFNB), dinitrobenzene (DNB), dinitrophenol (DNP), nitrobenzene (NB), p- nitroaniline (PNA), and p-nitrobenzoic acid (PNBA). Two milliliters of 50 times diluted NCQD were used for the experiment and each analyte solution was added to the NCQD once. Following excitation at 290 nm, the fluorescence emission spectra were captured at 420 nm. It was observed that the intensity of NCQD was dropped and its wavelength slightly altered to 460 nm upon the addition of picric acid. The spectra showed that NCQD was very selective for picric acid because no other analyte changed the results (Fig. 3 (a)). The interference studies were also observed, using 2-NP, 3-NP, 4-NP, DCNB, DFNB, DNB, DNP, NB, PNA, and PNBA along with picric acid to estimate the clash of other analytes on picric acid complex with the NCQD. There was no difference in the spectrum obtained with the presence of different analytes proving that the presence of other analytes causes no interference (Fig. 3 (b)). As the picric acid concentration increased, the fluorescence intensity of the NCQD decreased. The titration was carried out till 40 µM of the picric acid was added to the NCQD solution. In less than five seconds after adding picric acid to the NCQD, the FL intensity significantly reduced (Fig. 4 (a)). To govern the LoD for the NCQD, a plot of the relative fluorescence response of NCQD (F0/F) versus the concentration of picric acid (in µM) was employed as shown in (Fig. 4 (b)). F 0 and F represent the fluorescence intensity before and after the addition of picric acid, respectively. The high correlation coefficient (R² = 0.99627) indicated a strong linear relationship within the concentration extent of 0 to 10 or 40 µM. Using the given formula, the LoD was calculated to be 10 nM. LOD = 3 \(\:\varvec{\sigma\:}\) /Slope The sign σ represents the standard deviation and LOD for this NCQD is proportionate to those of other carbon quantum dots. A comparison table for various carbon quantum dots can be found in Table S1. 3.1.2 MTT assay and Bioimaging studies: To ascertain the impact of sample NCQD on the MCF-7 (breast cancer) cell line, the MTT assay, also referred to as the cytotoxicity assay, was utilized. Additionally, the sample was separated into four concentrations (6.5, 12.5, 25, 50, and 100 µg/ml) to determine the cell inhibition rate. Following that, 100 µl of each concentration's sample was extracted, introduced to the MCF-7 cell, and left for 24 hours. Cells were progressively inhibited following the addition of each dose (Fig. 5). It was determined that the NCQD's IC 50 value was 35.95 µg/ml. The cells were suppressed up to 65.68% until the maximal concentration (100 µg/ml) was achieved. Additionally, the fluorescent bioimaging of MCF-7 breast cancer cells was performed using only NCQD, as illustrated in Fig. 6. No emission was detected in the absence of NCQD. The fluorescence image was displayed when 50ul of NCQD was added to the breast cancer cells with a concentration of 6 mg/ml. 3.1.3 Anti-bacterial studies: Using the well diffusion method, the invitro antibacterial activities of NCQD were evaluated against one gram-positive ( Staphylococcus aureus ) and one gram-negative ( Klebsiella pneumonia ) bacteria. NCQD samples were analyzed at three doses (10, 20, and 30 µg/ml). Each concentration was applied to a plate containing fully grown bacteria. The antibacterial test employed amoxicillin (10 µg/ml) as the reference, resulting in a 12mm inhibition rate. The zone of inhibition was found to increase in tandem with the concentration of NCQD. As seen in Fig. 7, the NCQD sample exhibited antibacterial activity against two species, namely Klebsiella pneumonia (8mm) and Staphylococcus aureus (9mm). The experiment was conducted in triplicates (n=3) S.No Pathogenic bacteria Zone of inhibition (mm) Standard (Amoxicillin) 10 ug 20 ug 30 ug 1. Staphylococcus aureus 05 07 08 12 2. Klebsiella pneumonia 05 07 09 12 3.2 Characterizations and application of Pd nanoparticles: The UV-visible analysis of Pd nanoparticles is described in FigureS2 . The findings indicated that although the NCQD contained two peaks, they were suppressed in the palladium nanoparticle scenario, which clearly indicates Pd (II) is reduced to Pd (0) [33]. For the determination of the surface morphology of palladium nanoparticles, FESEM analysis was used. The analysis showed that the nanoparticles demonstrate agglomerated spherical morphology, as depicted in Fig. 8. To determine the elements contained in the nanoparticles, EDAX mapping was also performed. In addition to palladium, carbon, nitrogen, and oxygen were present. Because of NCQD's interaction with the nanoparticles, these elements are present [33]. Phase purity, crystallinity, and structural evidence were assessed using p-XRD analysis on the palladium nanoparticles (Fig. 9). The diffraction peaks of palladium nanoparticles at 40.01°, 46.33°, 47.73°, and 81.93° line up with the reflection planes (111), (200), (220), and (311), respectively. Using the formula D= (.94λ)/βcosθ, the Pd nanoparticle’s crystalline size was found to be 4.4 nm. To substantiate the thermal stability of nanoparticles, thermogravimetric analysis (TGA) was used. It was conducted in a nitrogen environment between 35 and 800°C, with a heating rate of 20°C per minute (Fig. 10 (a)). The catalyst absorbed moisture during the synthesis phase, which caused the initial 5–6% breakdown. At 200–800°C, a significant weight loss of about 6% was seen due to the reduction of volatile solvents present in the NCQD. A total weight loss of around 11% at about 800°C was caused by the NCQD surface functional groups that were absorbed by the nanoparticles, demonstrating the resilience of the catalyst at high temperatures. According to Brunauer-Emmett-Teller (BET) analysis (Fig. 10 (b)), nanoparticles have a surface area of 67.360m 2 g -1 and a pore diameter of 1.431 nm. The nitrogen adsorption-desorption isotherm also demonstrated the characteristic of a mesoporous material that exhibited type II isotherm with a hysteresis loop, making it an excellent nano-catalyst for organic reactions. 3.3 Catalytic activities of Pd nanoparticles in denitrogenative cross-coupling reactions: The denitrogenative cross-coupling reactions were conducted to determine the catalytic activity of Pd nanoparticles. Phenyl hydrazine hydrochloride and iodobenzene were selected as the model reactants for the reaction process. The optimization reactions were conducted using solvents such as water, ethanol, DMSO, THF, toluene, acetonitrile, 1,4-dioxane, 1,4-dioxane: H 2 O (1:1), and EtOH: H 2 O (1:1) ( Table S2 Sl.no 1–18). Given that both the base and the reactant may dissolve in polar solvents, the analysis showed that the productivity was higher in the case of these solvents. The EtOH: H 2 O (1:1) solvent mixture, on the other hand, had the highest yield and was hence selected as the optimal condition for the remaining processes ( Table S2 Sl. No-18). Additionally, the impact of the base was also examined using several bases, including Na 2 CO 3 , KOH, NaOH, and K 2 CO 3 . Because Na 2 CO 3 had the highest yield of 89%, it was selected as the base for the optimization conditions. No more increments in the yield percentage were observed when the catalyst loading was increased. Accordingly, the following optimization parameters were used: Pd nanoparticles (3 mg), aryl halide (1 equivalent), phenylhydrazine derivative (1.1 equivalents), and Na 2 CO 3 (2.5 equivalents) at 80°C for six hours under open air conditions. A number of derivatives were examined by adhering to the optimization requirements, and the results showed an excellent yield ( Scheme 1 ). Column chromatography was used to purify the products, and H 1 NMR verified their purity. The yields of aryl iodide were superior to those of aryl bromide under these circumstances. 3.4 Catalytic activities of Pd nanoparticles in the reduction of nitro phenols: 3.4.1. Reduction of 4- Nitrophenol (4-NP): 4-Nitrophenol (4-NP) was naturally yellow at first, but after NaBH 4 was added, the solution's colour changed to a vivid yellow because 4-nitrophenolate was produced. In the UV-visible spectrum, the 4-NP solution showed an absorption maximum of 318 nm. When NaBH 4 solution was added, the solution's colour changed to bright yellow with a bathochromic shift to 400 nm, signifying the generation of 4-nitrophenolate, as seen in (Fig. 11 (a)). In the presence of 2 mg of Pd nanoparticles, the reaction took 100 seconds to reduce, and a new peak appeared at 303 nm, which was the formation of 4-aminophenol. The reaction was carried out with NaBH 4 and without the catalyst in order to comprehend the catalytic effect of the palladium nanoparticles. This outcome demonstrates that the peak ( Figure S3 ) remains unchanged. Concurrently, the experiment was carried out solely using the catalyst and without NaBH 4 , demonstrating that neither the enolate peak nor its strength changed. This suggests that, in order to reduce nitrophenol rapidly, this experiment needs both catalysts and NaBH 4 . Based on the chemical kinetic plot (Fig. 11 (b)), the rate constant was found to be 2.06× 10 − 2 s − 1 with an R 2 value of 0.9633. The concentration of NaBH 4 is higher, which indicates this reaction follows pseudo-first-order kinetics [43]. 3.4.2. Reduction of 2- Nitrophenol (2-NP): Similar to 4-NP, 2-NP is yellow, but it turned dark yellow when NaBH 4 was added. The aqueous solution of 2-NP, initially, revealed two peaks in the UV-visible spectrum at 278 and 351 nm. Upon adding the NaBH 4 solution, a bathochromic shift took place at 282 and 416 nm, demonstrating the generation of 2-nitrophenolate (Fig. 12 (a)). Both, the catalyst and no catalyst conditions were used in the optimization protocols. The spectrum did not alter when NaBH 4 was present and the catalyst was absent. Similarly, a reaction was carried out with and without NaBH 4 , and the spectra did not alter in either case. When catalyst and NaBH 4 were added, 2-NP decreased in 3 minutes, and a new peak began to emerge at 285 nm, which resulted in the production of 2-aminophenol. A pseudo-first order reaction occurred when the concentration of NaBH 4 was higher. It was determined that the R 2 value was 0.92377 and the rate constant was 0.3739 min − 1 shown in Fig. 12 (b). 3.4.3. Reduction of 3- Nitrophenol (3-NP): Similar to 2-NP and 4-NP, 3-NP exhibited a bathochromic shift from 273 nm and 335 nm to 290 nm and 395 nm, which resulted in the production of 3-nitrophenolate (Fig. 13 (a) ) . The spectrum did not vary whether the reaction was carried out with and without a catalyst or NaBH 4 . It took 7 minutes to decrease the 3-nitrophenol using both the catalyst and NaBH 4 . It was discovered that the R 2 value was 0.99106 and the rate constant was 0.13931 min − 1 as in Fig. 13 (b). The reduction of isomers of nitrophenol was conducted with the catalyst. The rate of reduction of the nitrophenols followed the order; 4-NP > 2-NP > 3-NP. Conclusion As demonstrated in the current work, amino acid-aided nitrogen-doped carbon quantum dots were prepared using a hydrothermal method. Sustainably, bottle gourd peel and arginine were used to make the NCQD. It offered a quantum yield of 28.03 percent and exhibited a vivid blue fluorescence color. This NCQD served as an antibacterial agent and was used as a fluorescent probe for the detection of picric acid and in bioimaging experiments for MCF-7 cells. This NCQD was also utilized as a stabilizing and reducing agent in synthesizing Pd nanoparticles, where Pd (II) was reduced to Pd (0). This nanoparticle catalyzed the reduction of nitrophenol and denitrogenative cross-coupling reactions. It helped to create a great yield because of its smaller size and larger surface area. Abbreviations NCQD-Nitrogen-doped carbon quantum dots PA-Picric acid Limit of detection - LoD Pd nanoparticles-Palladium nanoparticles MTT - 3-[4,5-dimethylthiazol-2-yl] 2,5-diphenyltetrazolium bromide UV- Ultra violet p-XRD- powder X-ray diffraction FT-IR- Fourier Transform Infrared TGA- Thermogravimetry analysis BET- Brunauer-Emmett-Teller 2-NP- Nitrophenol 3-NP- 3- nitrophenol 4-NP - 4-nitrophenol DCNB- Dichloronitrobenzene DFNB- Difluoronitrobenzene DNB- Dinitrobenzene DNP- Dinitrophenol NB- Nitrobenzene PNA - P- nitroaniline PNBA- P-nitrobenzoic acid Declarations Acknowledgment Namrata P. Hota conveys special gratitude to the Vellore Institute of Technology, which has given her financial assistance for the research scholarship. SIF-VIT is duly acknowledged. The authors thank Dr. R. Srinivasan, SSL-VIT for language editing. Author Contribution: Namrata Priyadarshini Hota carried out the work and wrote the manuscript, Saluja Diksha carried out the characterization of nanoaprticles, Nandhini Karthikeyan carried out the optical studies, Prakash Seenu carried out the analysis of the data, and Sathiyanarayanan Kulathu Iyer supervised the whole work and manuscript. Funding: There was no funding for this research. Data Availability: The main manuscript or supplemental information files include all the data information. Compliance with Ethical Standards Conflict of Interest: There is no conflict of interest. Ethics and Consent to Participate : Not applicable Consent for Publication: Not applicable. References Liu Y, Jiang L, Li B, Fan X, Wang W, Liu P, Xu S, Luo X (2019) Journal of Materials Chemistry B 7:3053-3058. Dubey V, Dubey N, Atri S, Kaur J, Dhoble SJ, in: Quantum Dots, Elsevier, 2023). 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Srivastava I, Khamo JS, Pandit S, Fathi P, Huang X, Cao A, Haasch RT, Nie S, Zhang K, Pan D (2019) Advanced Functional Materials 29:1902466. Nemiwal M, Kumar D (2021) Inorganic Chemistry Communications 128:108602. Limaye AS, Yhobu Z, Thrilokraj R, Budagumpi S, Dateer RB (2024) Colloids and Surfaces A: Physicochemical and Engineering Aspects 688:133555. Magano J, Dunetz JR (2011) Chemical Reviews 111:2177-2250. Magano J, Dunetz JR (2011) Chemical Reviews 111:2177-2250. Ng SS, Chen Z, Yuen OY, So CM (2022) Organic & Biomolecular Chemistry 20:1373-1378. Xu S, Song K, Li T, Tan B (2015) Journal of Materials Chemistry A 3:1272-1278. Kandathil V, Dateer RB, Sasidhar B, Patil SA, Patil SA (2018) Catalysis Letters 148:1562-1578. Chatterjee S, Bhattacharya SK (2018) ACS omega 3:12905-12913. Mosmann T (1983) Journal of immunological methods 65:55-63. Monks A, Scudiero D, Skehan P, Shoemaker R, Paull K, Vistica D, Hose C, Langley J, Cronise P, Vaigro-Wolff A (1991) JNCI: Journal of the National Cancer Institute 83:757-766. Boobalan T, Sethupathi M, Sengottuvelan N, Kumar P, Balaji P, Gulyás B, Padmanabhan P, Selvan ST, Arun A (2020) ACS Applied Nano Materials 3:5910-5919. Cyril N, George JB, Nair PV, Joseph L, Sunila C, Smitha V, Anila B, Sylas V (2020) Nano-Structures & Nano-Objects 22:100430. Scheme 1 Scheme 1 is available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files SupplimentaryFinal.docx GA.png GA Scheme1.png Scheme 1 Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 31 Mar, 2025 Reviews received at journal 22 Mar, 2025 Reviewers agreed at journal 15 Mar, 2025 Reviewers agreed at journal 13 Mar, 2025 Reviewers invited by journal 13 Mar, 2025 Editor assigned by journal 13 Mar, 2025 Submission checks completed at journal 13 Mar, 2025 First submitted to journal 06 Mar, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6170167","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":429228915,"identity":"e189dd3d-369d-4169-beb0-923b12332531","order_by":0,"name":"Namrata Priyadarshini Hota","email":"","orcid":"","institution":"Vellore Institute of Technology","correspondingAuthor":false,"prefix":"","firstName":"Namrata","middleName":"Priyadarshini","lastName":"Hota","suffix":""},{"id":429228916,"identity":"f0d4f542-1275-48bc-900a-873efb20ba33","order_by":1,"name":"Saluja Diksha","email":"","orcid":"","institution":"Vellore Institute of Technology","correspondingAuthor":false,"prefix":"","firstName":"Saluja","middleName":"","lastName":"Diksha","suffix":""},{"id":429228918,"identity":"c770c6a8-ce0e-407a-b09b-bb5128decf90","order_by":2,"name":"Nandhini Karthikeyan","email":"","orcid":"","institution":"Vellore Institute of Technology","correspondingAuthor":false,"prefix":"","firstName":"Nandhini","middleName":"","lastName":"Karthikeyan","suffix":""},{"id":429228919,"identity":"e61cd076-d0f2-4854-b3f5-c83aa442f7b1","order_by":3,"name":"Prakash Seenu","email":"","orcid":"","institution":"Vellore Institute of Technology","correspondingAuthor":false,"prefix":"","firstName":"Prakash","middleName":"","lastName":"Seenu","suffix":""},{"id":429228921,"identity":"b946e9db-3ee6-4c33-a2bf-51e4e9365b58","order_by":4,"name":"Sathiyanarayanan Kulathu Iyer","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/0lEQVRIiWNgGAWjYHACNoYEICkBYn5sAJGMjQfw62BGaGGc2QCiGRsIa2GAamHmbYDYhleLfPv5Yw8ettkxSM7IPfjZdodNnW77YaAtNTbRuLQYnElmN0hsS2aQlshLls49kyZhdiYRqOVYWm4DLi0MyWwSiW3MDHISOQbSuW2HJcwOALUwNhzGqUW+/zFISz1Ii/FvS5CW8w/xa2G4AbblMNBhOWbSjCAtNwjYYnDjsZlEwrnjDJI9b8wse9vSJLfdANqSgMcv8v2JzyR/lFUzSBzPMb7xs82G3+x8+sMHH2pscDsMBBjZGOpRFSTgUw4GfwiqGAWjYBSMgpEMABAzXHgHSNx9AAAAAElFTkSuQmCC","orcid":"","institution":"Vellore Institute of Technology","correspondingAuthor":true,"prefix":"","firstName":"Sathiyanarayanan","middleName":"Kulathu","lastName":"Iyer","suffix":""}],"badges":[],"createdAt":"2025-03-06 11:38:37","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6170167/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6170167/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":78677708,"identity":"9e9b73c1-e928-453f-a86f-b937fb4e8cb1","added_by":"auto","created_at":"2025-03-17 13:56:39","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":62937,"visible":true,"origin":"","legend":"\u003cp\u003eFT-IR analysis of NCQD\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/171c2be67a0a6d1fc5585b26.png"},{"id":78677710,"identity":"54b05792-1631-46af-bbda-9beee1e548c1","added_by":"auto","created_at":"2025-03-17 13:56:39","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":120337,"visible":true,"origin":"","legend":"\u003cp\u003e(a) UV-VIS spectra of NCQD, and (b) NCQD with different wavelength\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/cf5ff0dece23a402a820464f.png"},{"id":78677716,"identity":"ccd8afe2-478a-476e-838a-4ca9e5fba0dc","added_by":"auto","created_at":"2025-03-17 13:56:39","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":177934,"visible":true,"origin":"","legend":"\u003cp\u003e(a)Selectivity studies of NCQD with different analytes, (b) Interference of PA with different analytes.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/0fbdb1910e004b2524fbca48.png"},{"id":78679689,"identity":"7fdebdb1-187e-4fda-b32e-35646e397f88","added_by":"auto","created_at":"2025-03-17 14:12:39","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":148531,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Titration of NCQD with PA, (b) calibration plot of NCQD with variation of different concentrations of PA\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/e63e8088ace9fe1f2ddd855b.png"},{"id":78678148,"identity":"2637d64f-4162-48b4-b09e-bab9123d0375","added_by":"auto","created_at":"2025-03-17 14:04:39","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":57205,"visible":true,"origin":"","legend":"\u003cp\u003eMTT assay- cell inhibition % determination of NCQD\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/440bf8b3fcd8460962e68c53.png"},{"id":78677715,"identity":"b11a0e8c-b100-4ac3-9449-3bdb40e42e4a","added_by":"auto","created_at":"2025-03-17 13:56:39","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":650655,"visible":true,"origin":"","legend":"\u003cp\u003eBioimaging study of MCF-7 cell with NCQD\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/233fa9728c2e9f8a51097148.png"},{"id":78678159,"identity":"21136b85-4d01-47a9-b46b-3c0da24651ff","added_by":"auto","created_at":"2025-03-17 14:04:40","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":811943,"visible":true,"origin":"","legend":"\u003cp\u003eAntibacterial activity of (a) \u003cem\u003eKlebsiella pneumonia\u003c/em\u003e and (b) \u003cem\u003eStaphylococcus aureus\u003c/em\u003e\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/f3839430ea318d8ccfbbf0c8.png"},{"id":78678152,"identity":"600681f5-0742-4325-9dca-4898a7da6eab","added_by":"auto","created_at":"2025-03-17 14:04:39","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":736418,"visible":true,"origin":"","legend":"\u003cp\u003eFESEM and EDAX mapping of palladium nanoparticles.\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/a9b5331159876bd05770901b.png"},{"id":78677721,"identity":"a558df67-62ac-4b0e-b8bb-9f292dff4c47","added_by":"auto","created_at":"2025-03-17 13:56:39","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":31151,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003ep\u003c/em\u003e-XRD analysis of palladium nanoparticles\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/2a79a8676bb2318ca309fedd.png"},{"id":78678158,"identity":"00559b6b-f8d5-4325-a57e-734bb9a7eede","added_by":"auto","created_at":"2025-03-17 14:04:40","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":65197,"visible":true,"origin":"","legend":"\u003cp\u003e(a)TGA analysis, (b) BET analysis of palladium nanoparticles.\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/dab6b295d4e095d49d962f20.png"},{"id":78677727,"identity":"2b39f8f4-5606-4c3f-bf00-0610624a4058","added_by":"auto","created_at":"2025-03-17 13:56:40","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":196407,"visible":true,"origin":"","legend":"\u003cp\u003eReduction of 4-NP with Pd nanoparticles\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/4ab6f3063f4a7c2f6711472c.png"},{"id":78677740,"identity":"ab837370-6e37-4bf2-a820-6c502c9b72b6","added_by":"auto","created_at":"2025-03-17 13:56:40","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":179376,"visible":true,"origin":"","legend":"\u003cp\u003eReduction of 2-NP with Pd nanoparticles\u003c/p\u003e","description":"","filename":"12.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/e2f0280d66f72e2ebfd68b13.png"},{"id":78678155,"identity":"4c828fea-76c8-45f4-a6c1-e0f0631ff407","added_by":"auto","created_at":"2025-03-17 14:04:40","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":169574,"visible":true,"origin":"","legend":"\u003cp\u003eReduction of 3-NP with Pd nanoparticles\u003c/p\u003e","description":"","filename":"13.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/33fe018aad8ee5971089b920.png"},{"id":78681497,"identity":"b335a6aa-c43d-4609-9067-246c28d2a36e","added_by":"auto","created_at":"2025-03-17 14:28:42","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4679053,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/e109dca0-9f50-4eaf-8e16-b19ba77fc2bf.pdf"},{"id":78680120,"identity":"4fac561b-b9ca-4be3-af61-258a73fd36d4","added_by":"auto","created_at":"2025-03-17 14:20:39","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":1466606,"visible":true,"origin":"","legend":"","description":"","filename":"SupplimentaryFinal.docx","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/1a4bbbf870cbfd0cb17a61ef.docx"},{"id":78679686,"identity":"d00929e5-d4fa-41f5-bf15-c8c0d8cac7b3","added_by":"auto","created_at":"2025-03-17 14:12:39","extension":"png","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":211947,"visible":true,"origin":"","legend":"\u003cp\u003eGA\u003c/p\u003e","description":"","filename":"GA.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/79aaa25e3475324522845edf.png"},{"id":78677717,"identity":"3b39df82-0c06-4950-b8fb-efaa04f538f5","added_by":"auto","created_at":"2025-03-17 13:56:39","extension":"png","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":83448,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eScheme 1\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Scheme1.png","url":"https://assets-eu.researchsquare.com/files/rs-6170167/v1/b579e93c76dfa63364687a04.png"}],"financialInterests":"No competing interests reported.","formattedTitle":"Amino acid-assisted carbon quantum dots for bioimaging, Picric acid detection, antibacterial activity, and prefabrication of Pd nanoparticles as a potent nanocatalyst for coupling reactions and reduction of nitrophenols","fulltext":[{"header":"1. Introductions","content":"\u003cp\u003eIn past decades, Carbon quantum dots (CQDs) have transpired as a center of attraction ascribed to their low toxicity, greater quantum yield, luminescence, biocompatibility, high photostability, and ease of synthesis [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. These CQDs are renowned for their applications like analyte sensing [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], bioimaging, catalysis [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], photocatalysis [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], gene delivery, and drug delivery [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], When the single-walled carbon nanotubes (SWCT) were being purified by Xu et. al., in 2004 they inadvertently discovered \u0026ldquo;Carbon quantum dots\u0026rdquo;. Then in 2006, Sun et al. effortlessly synthesized surface passivated emissive fluorescent carbon dots and coined the term \u0026lsquo;Carbon quantum dots\u0026rsquo; [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. These quasispherical nanocrystal CQDs are zero-dimensional, and the size is less than 10 nm [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. On that account, several synthetic methodologies such as top-down and bottom-up approaches have been followed. chemical oxidation [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], plasma therapy [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], arc discharge [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], electrochemical exfoliation [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], and laser ablation [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] are top-down methods, that necessitate sophisticated machines and a large amount of energy, which are both time-consuming and costly. Bottom-up synthesis, on the other hand, is eco-friendly, cost-effective, and environmentally beneficial [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], making it a greener technique. The bottom-up techniques include microwave irradiation [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], solvothermal [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], hydrothermal [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], and pyrolysis [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Hydrothermal is the most sustainable way to create an eco-friendly, non-toxic fluorescent CQD among these bottom-up strategies. However, the CQD generated from sole biomass has a lower quantum yield (\u0026lt;\u0026thinsp;10%), but doping heteroatoms like nitrogen [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e], sulfur [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], phosphorus [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], etc. would boost the quantum yield, which is popularly known as surface passivation [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. As the CQD surfaces are covered up with diverse functional groups, heteroatom-doped CQD can be used as a sensor as well as a possible candidate for antibacterial [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] and antifungal drugs, bioimaging, and catalysis.\u003c/p\u003e \u003cp\u003eThe primary focus of current research is the detection of hazardous analytes, particularly from water. Heavy metals and toxic analytes are found in harmful substances from various sources, particularly industry, which harm surface and subsurface water, thereby endangering living beings [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Picric acid (PA), often referred to as 2,4,6 trinitrophenol (TPN), is a water-soluble and poisonous analyte that finds extensive application as a reagent in the dye, pharmaceutical, and synthetic chemical industries [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Lower concentrations of these TNPs can also result in several health problems, including cancer, lung damage, eye damage, and respiratory disorders [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. M. K. Meheto et al. (2023) synthesized CQD from malic acid and urea in microwave-assisted pyrolysis method for picric acid detection [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e], Arunkumar K. et. al. (2020) synthesized CQD from thiourea and citric acid in pyrolysis method for selectively detecting picric acid [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e], in the hydrothermal method, Y. Wang et. al. (2018) synthesized CQD from ethylene diamine and mandelic acids for the detection of picric acid [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThese quantum dots have well-established electron-withdrawing and donating potential. They have the adaptability to lend and receive electrons from the electron-lacking and electron-abundant groups [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. The CQD\u0026rsquo;s surface covers a range of functional groups that could be responsible for synthesizing metal nanoparticles, where these CQDs function as reducing and supporting agents. These CQDs can be used for both sensing and bioimaging studies as well as the creation of metal nanoparticles. Apart from these, the metal nanoparticles possess tremendous applications in the catalysis field, hydrogen evolution [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e], reduction of toxic nitrophenols [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e], etc.\u003c/p\u003e \u003cp\u003eThe carbon-carbon (C-C) coupling reaction has always been the ultimate intriguing topic to investigate in Organic Chemistry. The biaryl compounds found in C-C coupling processes are used in a wide range of sectors, such as natural goods, plastics, and pharmaceuticals [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. These compounds can be produced by palladium complexes with ligands (such as phosphine, imidazole, and N-heterocyclic carbenes) that function as catalysts [\u003cspan additionalcitationids=\"CR36\" citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. Nevertheless, the synthesis of these chemicals is more labor-intensive and costly due to the palladium catalysts. To overcome these problems, these molecules can be synthesized using a variety of nanoparticles. Numerous methods exist for synthesizing palladium nanoparticles, including quantum dots [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e] and green methods [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn this study, we show that nitrogen-doped carbon quantum dots can be made hydrothermally by combining arginine and bottle gourd peel. This NCQD functions as an antibacterial agent, a fluorophore for selectively detecting picric acid, and for bioimaging investigation of the MCF 7 (breast cancer cells) cell line. In the process of synthesizing palladium nanoparticles, the NCQD is also employed as a reducing and supporting agent. These palladium nanoparticles catalyze the reduction of nitrophenols and denitrogenative coupling.\u003c/p\u003e"},{"header":"2. Experimental","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Materials\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe required solvents and chemicals were purchased from chemical retailers such as Sigma Aldrich, Avra, TCI, etc. The Hitachi (model 2910) instrument was used to investigate (ultra violet) UV-visible absorption studies. To investigate the fluorescence emission studies, a Hitachi (model F-7000) instrument was used. Surface area analysis was done by Quantachrome USA Model AutosorbiQ instruments. Powder-X-ray diffraction (P-XRD) was performed by Bruker, D8-Advance P-XRD instrument. JASCO 4100 spectrometer was used to record Fourier Transform Infrared (FTIR) data. To know the chemical structure of the synthesized molecules, proton Nuclear magnetic resonance (NMR) spectroscopy was used by using a Bruker Ascent 400 Hz spectrometer. To measure the chemical shift, CDCl\u003csub\u003e3\u003c/sub\u003e was used as solvent and TMS was used as internal standard.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Preparation of NCQD\u003c/h2\u003e \u003cp\u003eA sustainable hydrothermal technique was utilized to prepare the NCQD. Bottle gourd was used as the plant source while arginine was used as the nitrogen source. In a Teflon coated hydrothermal bomb, 1 g of bottle gourd peel and 200 mg of arginine were added, along with 50 ml of water. For six hours, the reaction mixture was held in a muffle furnace. The created NCQD was left outside overnight to reach room temperature. After that, the NCQD was centrifuged for 15 minutes at 4000 RPM to get rid of the residue. It was syringe-filtered and stored in the fridge. NCQD exhibited a strong blue fluorescence upon exposure to UV light. The NCQD was then applied to a variety of applications, including sensing, bioimaging, antimicrobial activity, and palladium nanoparticle production.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Fluorescent detection of Picric acid\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e1 mmol stock solutions were prepared for each analyte using double-distilled water, and it was subsequently diluted to a concentration of 100\u0026micro;M. A cuvette was filled with two milliliters of 50 times diluted NCQD, and the emission and excitation wavelengths were then recorded. To record the Fluorescence emission 300 nm was opted as the excitation wavelength. Then, 100 \u0026micro;L of each anion was combined with 2 ml of NCQD one at a time, and the fluorescence intensity was recorded. In contrast to all other analytes, picric acid was seen to exhibit a change in fluorescence intensity, indicating that this specific NCQD specifically senses picric acid.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Protocols for MTT Assay\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eMTT stands for 3-[4,5-dimethylthiazol-2-yl] 2,5-diphenyltetrazolium bromide which is a yellow water-soluble tetrazolium salt. MCF7 breast cancer cell was collected from the National Centre for Cell Sciences (NCCS). The collected cell was cultivated in eagles Minimum Essential Medium with 10% fetal bovine serum. The cells were retained in 95% air, 5% CO\u003csub\u003e2\u003c/sub\u003e, 100% relative humidity, and at 37\u003csup\u003eo\u003c/sup\u003eC. This MTT reacts with the mitochondrial enzyme in the living cells and letting them react with the living cells with an incubation period of 48h [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. After the time duration, 15 \u0026micro;l of MTT (after maintaining the pH with phosphate saline buffer) was solubilized in 100 \u0026micro;l of DMSO and the absorbance was recorded at 570 nm using a microplate reader [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cb\u003eProcedure for bioimaging studies of NCQD\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe procedure involved seeding 5 x 10\u003csup\u003e5\u003c/sup\u003e MCF 7 cells/ml into a 24-well tissue culture plate, followed by treatment with 6 \u0026micro;g/ml of NCQD in DMEM media without the serum. The tissue cultured plate was nurtured for 24 hours at 37\u0026deg;C with 5% CO\u003csub\u003e2\u003c/sub\u003e. After the nurturing period, 50 \u0026micro;L each of ethidium bromide and acridine orange (1 mg/ml) were added to the wells and delicately mixed. Eventually, the plate was centrifuged at 800 rpm for 2 minutes and inspected within an hour. About 100 cells were perceived by using a fluorescence microscope and a fluorescent filter.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Procedure for antibacterial activities of NCQD\u003c/h2\u003e \u003cp\u003eAfter being pre-cultured in nutrient broth for an entire night at 37\u0026deg;C in a rotary shaker, the gram-positive bacteria Staphylococcus aureus and the gram-negative bacteria Klebsiella pneumonia were centrifuged for five minutes at 10,000 rpm, pelletized and the pellet was suspended in double distilled water, and the cell density was standardized spectrophotometrically (A610 nm). Using a sterile spatula, the conidia were scraped off the Petri dishes after adding 8 to 10 milliliters of distilled water. A spectrophotometer (A595nm) was used to regulate the spore density of each bacterium to reach a final concentration of roughly 105 spores/ml.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.6 Synthesis of Pd nanoparticles\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eNCQD was used in the preparation of Pd nanoparticles. When synthesizing Pd nanoparticles, the NCQD is used as a stabilizing and reducing agent. The protocol calls for adding 100 milliliters of 0.02M Pd (OAc)\u003csub\u003e2\u003c/sub\u003e to a round-bottom flask, sonicating it for five minutes, and then keeping it in an oil bath at 80 degrees Celsius while stirring it for a few more minutes. Subsequently, the solution was progressively mixed with 20 milliliters of NCQD and allowed to remain at that temperature for two hours. As can be seen, the color of the solution changed to black from light brown, signifying the creation of Pd nanoparticles as well as the reduction of Pd (II) to Pd (0) [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. The solution was centrifuged multiple times with water, ethanol, and acetone to eliminate any undesired constituents from the synthesized nanoparticles when it reached room temperature and then stored for drying. After being dried and milled into a fine powder, the Pd nanoparticles were subsequently submitted for several types of characterizations. Furthermore, it is utilized as a catalyst for the reduction of nitrophenol and denitrogenative cross-coupling processes.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and discussion","content":"\u003cdiv id=\"Sec10\"\u003e\n \u003ch2\u003e3.1 Characterization and optical behavior of NCQD:\u003c/h2\u003e\n \u003cdiv\u003e\n \u003cp\u003eSince the NCQD's surface is covered with a variety of functional groups, FTIR analysis was performed, and the results indicated that the spectrum had notable peaks for several of these functional groups Fig.\u0026nbsp;1 The strong band at 3344 cm\u003csup\u003e-1\u003c/sup\u003e clearly demonstrates the asymmetric stretching of the -OH/NH bond [42]. Peaks at 2972 cm\u003csup\u003e-1\u003c/sup\u003e and 2880 cm\u003csup\u003e-1\u003c/sup\u003e are affiliated with -C-H groups; similarly, peaks at 1671, 1453, 1380, 1090, 1045, and 880 cm\u003csup\u003e-1\u003c/sup\u003e are associated with amide C = O, alkane CH, phenol OH, amine C-N, anhydride C-O stretching, and alkene C = C.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eMoreover, both UV-visible and fluorescence spectra were recorded for studying optical characteristics (Fig.\u0026nbsp;2 (a)). The NCQD revealed a vivid blue colour under UV light, but to the unaided sight, they seemed yellow. One peak at 226 nm in the matching UV spectrum represents the π-π* transition brought on by C = C and C = N bonds, while the other two peaks at 275 and 350 nm are in charge of the n-π* transition brought on by C = O bonds. The NCQD exhibited a vivid blue emission at 450 nm after exiting at 290 nm, demonstrating its luminous nature. Additionally, these carbon dots exhibited excitation-dependent photoluminescence (PL), which might have been caused by flaws in the NCQD size and surface (Fig.\u0026nbsp;2 (b)). The quantum yield of the NCQD was found to be 29.40% using quinine sulfate as a reference. There was no appreciable change observed in the fluorescence spectra after irradiation for one hour at 290nm.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eLater, pH studies were taken into account, solutions with a pH range of 2 to 12 were made using 0.1M HCl and NaOH, and a pH meter was used to determine the necessary pH value. The study revealed that the FL intensity began to drop at pH 2 and continued to rise until it reached the neutral pH of 7. This pattern resulted from protonation brought on by functional groups such as (-OH, -NH) on the NCQD surface. The intensity was observed to drastically drop when the pH became basic (\u003cstrong\u003eFigure S1)\u003c/strong\u003e. The fact that the maximum intensity was at neutral pH nevertheless shows how appropriate a neutral pH value is for the bioimaging and sensing investigations.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec11\"\u003e\n \u003ch2\u003e3.1.1 Selective detection of Picric acid\u003c/h2\u003e\n \u003cp\u003eThe earlier synthesized NCQD was used as a highly selective fluorophore to detect picric acid. The interaction with NCQD was assessed using a range of competitive ions and acids, such as 2-nitrophenol (2-NP), 3- nitrophenol (3-NP), 4-nitrophenol (4-NP), dichloronitrobenzene (DCNB), difluoronitrobenzene (DFNB), dinitrobenzene (DNB), dinitrophenol (DNP), nitrobenzene (NB), p- nitroaniline (PNA), and p-nitrobenzoic acid (PNBA). Two milliliters of 50 times diluted NCQD were used for the experiment and each analyte solution was added to the NCQD once. Following excitation at 290 nm, the fluorescence emission spectra were captured at 420 nm. It was observed that the intensity of NCQD was dropped and its wavelength slightly altered to 460 nm upon the addition of picric acid. The spectra showed that NCQD was very selective for picric acid because no other analyte changed the results (Fig.\u0026nbsp;3 (a)). The interference studies were also observed, using 2-NP, 3-NP, 4-NP, DCNB, DFNB, DNB, DNP, NB, PNA, and PNBA along with picric acid to estimate the clash of other analytes on picric acid complex with the NCQD. There was no difference in the spectrum obtained with the presence of different analytes proving that the presence of other analytes causes no interference (Fig.\u0026nbsp;3 (b)).\u003c/p\u003e\n \u003cp\u003eAs the picric acid concentration increased, the fluorescence intensity of the NCQD decreased. The titration was carried out till 40 µM of the picric acid was added to the NCQD solution. In less than five seconds after adding picric acid to the NCQD, the FL intensity significantly reduced (Fig.\u0026nbsp;4 (a)). To govern the LoD for the NCQD, a plot of the relative fluorescence response of NCQD (F0/F) versus the concentration of picric acid (in µM) was employed as shown in (Fig.\u0026nbsp;4 (b)). F\u003csub\u003e0\u003c/sub\u003e and F represent the fluorescence intensity before and after the addition of picric acid, respectively. The high correlation coefficient (R² = 0.99627) indicated a strong linear relationship within the concentration extent of 0 to 10 or 40 µM. Using the given formula, the LoD was calculated to be 10 nM.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eLOD = 3\u003c/strong\u003e \\(\\:\\varvec{\\sigma\\:}\\) \u003cstrong\u003e/Slope\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eThe sign σ represents the standard deviation and LOD for this NCQD is proportionate to those of other carbon quantum dots. A comparison table for various carbon quantum dots can be found in \u003cstrong\u003eTable S1.\u003c/strong\u003e\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec12\"\u003e\n \u003ch2\u003e3.1.2 MTT assay and Bioimaging studies:\u003c/h2\u003e\n \u003cdiv\u003e\n \u003cp\u003eTo ascertain the impact of sample NCQD on the MCF-7 (breast cancer) cell line, the MTT assay, also referred to as the cytotoxicity assay, was utilized. Additionally, the sample was separated into four concentrations (6.5, 12.5, 25, 50, and 100 µg/ml) to determine the cell inhibition rate. Following that, 100 µl of each concentration's sample was extracted, introduced to the MCF-7 cell, and left for 24 hours. Cells were progressively inhibited following the addition of each dose (Fig. 5). It was determined that the NCQD's \u003cstrong\u003eIC 50\u003c/strong\u003e value was 35.95 µg/ml. The cells were suppressed up to 65.68% until the maximal concentration (100 µg/ml) was achieved. Additionally, the fluorescent bioimaging of MCF-7 breast cancer cells was performed using only NCQD, as illustrated in Fig. 6. No emission was detected in the absence of NCQD. The fluorescence image was displayed when 50ul of NCQD was added to the breast cancer cells with a concentration of 6 mg/ml.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec13\"\u003e\n \u003ch2\u003e3.1.3 Anti-bacterial studies:\u003c/h2\u003e\n \u003cp\u003eUsing the well diffusion method, the invitro antibacterial activities of NCQD were evaluated against one gram-positive (\u003cem\u003eStaphylococcus aureus\u003c/em\u003e) and one gram-negative (\u003cem\u003eKlebsiella pneumonia\u003c/em\u003e) bacteria. NCQD samples were analyzed at three doses (10, 20, and 30 µg/ml). Each concentration was applied to a plate containing fully grown bacteria. The antibacterial test employed amoxicillin (10 µg/ml) as the reference, resulting in a 12mm inhibition rate. The zone of inhibition was found to increase in tandem with the concentration of NCQD. As seen in Fig. 7, the NCQD sample exhibited antibacterial activity against two species, namely \u003cem\u003eKlebsiella pneumonia\u003c/em\u003e (8mm) and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e (9mm).\u003c/p\u003e\n \u003cdiv\u003eThe experiment was conducted in triplicates (n=3)\u003c/div\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"614\"\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 45px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eS.No\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003ePathogenic bacteria\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd colspan=\"3\" valign=\"top\" style=\"width: 225px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eZone of inhibition (mm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd valign=\"top\" style=\"width: 163px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eStandard\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(Amoxicillin)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e10 ug\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e20 ug\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e30 ug\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd valign=\"top\" style=\"width: 163px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd valign=\"top\" style=\"width: 45px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e1.\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003e\u003cem\u003eStaphylococcus aureus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e05\u003c/p\u003e\n \u003c/td\u003e\u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e07\u003c/p\u003e\n \u003c/td\u003e\u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e08\u003c/p\u003e\n \u003c/td\u003e\u003ctd valign=\"top\" style=\"width: 163px;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd valign=\"top\" style=\"width: 45px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e2.\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003e\u003cem\u003eKlebsiella pneumonia\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e05\u003c/p\u003e\n \u003c/td\u003e\u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e07\u003c/p\u003e\n \u003c/td\u003e\u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e09\u003c/p\u003e\n \u003c/td\u003e\u003ctd valign=\"top\" style=\"width: 163px;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/table\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec14\"\u003e\n \u003ch2\u003e3.2 Characterizations and application of Pd nanoparticles:\u003c/h2\u003e\n \u003cdiv\u003e\n \u003cp\u003eThe UV-visible analysis of Pd nanoparticles is described in \u003cstrong\u003eFigureS2\u003c/strong\u003e. The findings indicated that although the NCQD contained two peaks, they were suppressed in the palladium nanoparticle scenario, which clearly indicates Pd (II) is reduced to Pd (0) [33]. For the determination of the surface morphology of palladium nanoparticles, FESEM analysis was used. The analysis showed that the nanoparticles demonstrate agglomerated spherical morphology, as depicted in Fig.\u0026nbsp;8. To determine the elements contained in the nanoparticles, EDAX mapping was also performed. In addition to palladium, carbon, nitrogen, and oxygen were present. Because of NCQD's interaction with the nanoparticles, these elements are present [33].\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003ePhase purity, crystallinity, and structural evidence were assessed using p-XRD analysis on the palladium nanoparticles (Fig.\u0026nbsp;9). The diffraction peaks of palladium nanoparticles at 40.01°, 46.33°, 47.73°, and 81.93° line up with the reflection planes (111), (200), (220), and (311), respectively. Using the formula D= (.94λ)/βcosθ, the Pd nanoparticle’s crystalline size was found to be 4.4 nm.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eTo substantiate the thermal stability of nanoparticles, thermogravimetric analysis (TGA) was used. It was conducted in a nitrogen environment between 35 and 800°C, with a heating rate of 20°C per minute (Fig.\u0026nbsp;10 (a)). The catalyst absorbed moisture during the synthesis phase, which caused the initial 5–6% breakdown. At 200–800°C, a significant weight loss of about 6% was seen due to the reduction of volatile solvents present in the NCQD. A total weight loss of around 11% at about 800°C was caused by the NCQD surface functional groups that were absorbed by the nanoparticles, demonstrating the resilience of the catalyst at high temperatures.\u003c/p\u003e\n \u003cp\u003eAccording to Brunauer-Emmett-Teller (BET) analysis (Fig.\u0026nbsp;10 (b)), nanoparticles have a surface area of 67.360m\u003csup\u003e2\u003c/sup\u003eg\u003csup\u003e-1\u003c/sup\u003e and a pore diameter of 1.431 nm. The nitrogen adsorption-desorption isotherm also demonstrated the characteristic of a mesoporous material that exhibited type II isotherm with a hysteresis loop, making it an excellent nano-catalyst for organic reactions.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec15\"\u003e\n \u003ch2\u003e3.3 Catalytic activities of Pd nanoparticles in denitrogenative cross-coupling reactions:\u003c/h2\u003e\n \u003cp\u003eThe denitrogenative cross-coupling reactions were conducted to determine the catalytic activity of Pd nanoparticles. Phenyl hydrazine hydrochloride and iodobenzene were selected as the model reactants for the reaction process. The optimization reactions were conducted using solvents such as water, ethanol, DMSO, THF, toluene, acetonitrile, 1,4-dioxane, 1,4-dioxane: H\u003csub\u003e2\u003c/sub\u003eO (1:1), and EtOH: H\u003csub\u003e2\u003c/sub\u003eO (1:1) (\u003cstrong\u003eTable S2\u003c/strong\u003e Sl.no 1–18). Given that both the base and the reactant may dissolve in polar solvents, the analysis showed that the productivity was higher in the case of these solvents. The EtOH: H\u003csub\u003e2\u003c/sub\u003eO (1:1) solvent mixture, on the other hand, had the highest yield and was hence selected as the optimal condition for the remaining processes (\u003cstrong\u003eTable S2\u003c/strong\u003e Sl. No-18). Additionally, the impact of the base was also examined using several bases, including Na\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e, KOH, NaOH, and K\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e. Because Na\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e had the highest yield of 89%, it was selected as the base for the optimization conditions. No more increments in the yield percentage were observed when the catalyst loading was increased.\u003c/p\u003e\n \u003cp\u003eAccordingly, the following optimization parameters were used: Pd nanoparticles (3 mg), aryl halide (1 equivalent), phenylhydrazine derivative (1.1 equivalents), and Na\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e (2.5 equivalents) at 80°C for six hours under open air conditions. A number of derivatives were examined by adhering to the optimization requirements, and the results showed an excellent yield (\u003cstrong\u003eScheme 1\u003c/strong\u003e). Column chromatography was used to purify the products, and H\u003csup\u003e1\u003c/sup\u003e NMR verified their purity. The yields of aryl iodide were superior to those of aryl bromide under these circumstances.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec16\"\u003e\n \u003ch2\u003e3.4 Catalytic activities of Pd nanoparticles in the reduction of nitro phenols:\u003c/h2\u003e\n \u003cdiv id=\"Sec17\"\u003e\n \u003ch2\u003e3.4.1. Reduction of 4- Nitrophenol (4-NP):\u003c/h2\u003e\n \u003cp\u003e4-Nitrophenol (4-NP) was naturally yellow at first, but after NaBH\u003csub\u003e4\u003c/sub\u003e was added, the solution's colour changed to a vivid yellow because 4-nitrophenolate was produced. In the UV-visible spectrum, the 4-NP solution showed an absorption maximum of 318 nm. When NaBH\u003csub\u003e4\u003c/sub\u003e solution was added, the solution's colour changed to bright yellow with a bathochromic shift to 400 nm, signifying the generation of 4-nitrophenolate, as seen in (Fig. 11 (a)). In the presence of 2 mg of Pd nanoparticles, the reaction took 100 seconds to reduce, and a new peak appeared at 303 nm, which was the formation of 4-aminophenol. The reaction was carried out with NaBH\u003csub\u003e4\u003c/sub\u003e and without the catalyst in order to comprehend the catalytic effect of the palladium nanoparticles. This outcome demonstrates that the peak (\u003cstrong\u003eFigure S3\u003c/strong\u003e) remains unchanged. Concurrently, the experiment was carried out solely using the catalyst and without NaBH\u003csub\u003e4\u003c/sub\u003e, demonstrating that neither the enolate peak nor its strength changed. This suggests that, in order to reduce nitrophenol rapidly, this experiment needs both catalysts and NaBH\u003csub\u003e4\u003c/sub\u003e. Based on the chemical kinetic plot (Fig.\u0026nbsp;11 (b)), the rate constant was found to be 2.06× 10\u003csup\u003e− 2\u003c/sup\u003e s\u003csup\u003e− 1\u003c/sup\u003e with an R\u003csup\u003e2\u003c/sup\u003e value of 0.9633. The concentration of NaBH\u003csub\u003e4\u003c/sub\u003e is higher, which indicates this reaction follows pseudo-first-order kinetics [43].\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec18\"\u003e\n \u003ch2\u003e3.4.2. Reduction of 2- Nitrophenol (2-NP):\u003c/h2\u003e\n \u003cp\u003eSimilar to 4-NP, 2-NP is yellow, but it turned dark yellow when NaBH\u003csub\u003e4\u003c/sub\u003e was added. The aqueous solution of 2-NP, initially, revealed two peaks in the UV-visible spectrum at 278 and 351 nm. Upon adding the NaBH\u003csub\u003e4\u003c/sub\u003e solution, a bathochromic shift took place at 282 and 416 nm, demonstrating the generation of 2-nitrophenolate (Fig. 12 (a)). Both, the catalyst and no catalyst conditions were used in the optimization protocols. The spectrum did not alter when NaBH\u003csub\u003e4\u003c/sub\u003e was present and the catalyst was absent. Similarly, a reaction was carried out with and without NaBH\u003csub\u003e4\u003c/sub\u003e, and the spectra did not alter in either case. When catalyst and NaBH\u003csub\u003e4\u003c/sub\u003e were added, 2-NP decreased in 3 minutes, and a new peak began to emerge at 285 nm, which resulted in the production of 2-aminophenol. A pseudo-first order reaction occurred when the concentration of NaBH\u003csub\u003e4\u003c/sub\u003e was higher. It was determined that the R\u003csup\u003e2\u003c/sup\u003e value was 0.92377 and the rate constant was 0.3739 min\u003csup\u003e− 1\u003c/sup\u003e shown in Fig. 12 (b).\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec19\"\u003e\n \u003ch2\u003e3.4.3. Reduction of 3- Nitrophenol (3-NP):\u003c/h2\u003e\n \u003cp\u003eSimilar to 2-NP and 4-NP, 3-NP exhibited a bathochromic shift from 273 nm and 335 nm to 290 nm and 395 nm, which resulted in the production of 3-nitrophenolate (Fig.\u0026nbsp;13 (a)\u003cstrong\u003e)\u003c/strong\u003e. The spectrum did not vary whether the reaction was carried out with and without a catalyst or NaBH\u003csub\u003e4\u003c/sub\u003e. It took 7 minutes to decrease the 3-nitrophenol using both the catalyst and NaBH\u003csub\u003e4\u003c/sub\u003e. It was discovered that the R\u003csup\u003e2\u003c/sup\u003e value was 0.99106 and the rate constant was 0.13931 min \u003csup\u003e− 1\u003c/sup\u003e as in Fig. 13 (b).\u003c/p\u003e\n \u003cp\u003eThe reduction of isomers of nitrophenol was conducted with the catalyst. The rate of reduction of the nitrophenols followed the order; 4-NP \u0026gt; 2-NP \u0026gt; 3-NP.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eAs demonstrated in the current work, amino acid-aided nitrogen-doped carbon quantum dots were prepared using a hydrothermal method. Sustainably, bottle gourd peel and arginine were used to make the NCQD. It offered a quantum yield of 28.03 percent and exhibited a vivid blue fluorescence color. This NCQD served as an antibacterial agent and was used as a fluorescent probe for the detection of picric acid and in bioimaging experiments for MCF-7 cells. This NCQD was also utilized as a stabilizing and reducing agent in synthesizing Pd nanoparticles, where Pd (II) was reduced to Pd (0). This nanoparticle catalyzed the reduction of nitrophenol and denitrogenative cross-coupling reactions. It helped to create a great yield because of its smaller size and larger surface area.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eNCQD-Nitrogen-doped carbon quantum dots\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePA-Picric acid\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eLimit of detection - LoD\u003c/p\u003e\n\u003cp\u003ePd nanoparticles-Palladium nanoparticles\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMTT\u0026nbsp;-\u0026nbsp;3-[4,5-dimethylthiazol-2-yl] 2,5-diphenyltetrazolium bromide\u003c/p\u003e\n\u003cp\u003eUV- Ultra violet\u003c/p\u003e\n\u003cp\u003ep-XRD- powder X-ray diffraction\u003c/p\u003e\n\u003cp\u003eFT-IR- Fourier Transform Infrared\u003c/p\u003e\n\u003cp\u003eTGA- Thermogravimetry analysis\u003c/p\u003e\n\u003cp\u003eBET-\u0026nbsp;Brunauer-Emmett-Teller\u003c/p\u003e\n\u003cp\u003e2-NP- Nitrophenol\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e3-NP- 3- nitrophenol\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e4-NP - 4-nitrophenol\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDCNB- Dichloronitrobenzene\u003c/p\u003e\n\u003cp\u003eDFNB- Difluoronitrobenzene\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDNB- Dinitrobenzene\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDNP- Dinitrophenol\u003c/p\u003e\n\u003cp\u003eNB- Nitrobenzene\u003c/p\u003e\n\u003cp\u003ePNA - P- nitroaniline\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePNBA- P-nitrobenzoic acid\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNamrata P. Hota conveys special gratitude to the Vellore Institute of Technology, which has given her financial assistance for the research scholarship. SIF-VIT is duly acknowledged. The authors thank Dr. R. Srinivasan, SSL-VIT for language editing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contribution:\u0026nbsp;\u003c/strong\u003eNamrata Priyadarshini Hota carried out the work and wrote the manuscript, Saluja Diksha carried out the characterization of nanoaprticles, Nandhini Karthikeyan carried out the optical studies, Prakash Seenu carried out the analysis of the data, and Sathiyanarayanan Kulathu Iyer supervised the whole work and manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u0026nbsp;\u003c/strong\u003eThere was no funding for this research.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability:\u0026nbsp;\u003c/strong\u003eThe main manuscript or supplemental information files include all the data information.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompliance with Ethical Standards\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest:\u0026nbsp;\u003c/strong\u003eThere is no conflict of interest.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics and Consent to Participate\u003c/strong\u003e: Not applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for Publication:\u0026nbsp;\u003c/strong\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eLiu Y, Jiang L, Li B, Fan X, Wang W, Liu P, Xu S, Luo X (2019) Journal of Materials Chemistry B 7:3053-3058.\u003c/li\u003e\n\u003cli\u003eDubey V, Dubey N, Atri S, Kaur J, Dhoble SJ, in: Quantum Dots,\u003cem\u003e \u003c/em\u003eElsevier, 2023).\u003c/li\u003e\n\u003cli\u003eAnadebe VC, Thakur A, Okoye CC, Ezemagu IG, Guo L, Ebenso EE, in: Carbon Dots: Recent Developments and Future Perspectives,\u003cem\u003e \u003c/em\u003eACS Publications, 2024).\u003c/li\u003e\n\u003cli\u003eDas GS, Shim JP, Bhatnagar A, Tripathi KM, Kim T (2019) Scientific reports 9:15084.\u003c/li\u003e\n\u003cli\u003eWang H, Cheng C, Zhao J, Han F, Zhao G, Zhang Y, Wang Y (2024) Biosensors 14:40.\u003c/li\u003e\n\u003cli\u003eXu X, Ray R, Gu Y, Ploehn HJ, Gearheart L, Raker K, Scrivens WA (2004) Journal of the American Chemical Society 126:12736-12737.\u003c/li\u003e\n\u003cli\u003eSun Y-P, Zhou B, Lin Y, Wang W, Fernando KS, Pathak P, Meziani MJ, Harruff BA, Wang X, Wang H (2006) Journal of the American Chemical Society 128:7756-7757.\u003c/li\u003e\n\u003cli\u003eZhang X, Lu J, Li X, Chai L, Jiao Y (2017) New Journal of Chemistry 41:702-708.\u003c/li\u003e\n\u003cli\u003eGe G, Li L, Chen M, Wu X, Yang Y, Wang D, Zuo S, Zeng Z, Xiong W, Guo C (2022) Nanomaterials 12:986.\u003c/li\u003e\n\u003cli\u003eTyagi A, Tripathi KM, Singh N, Choudhary S, Gupta RK (2016) RSC advances 6:72423-72432.\u003c/li\u003e\n\u003cli\u003eLi W, Zhang Z, Kong B, Feng S, Wang J, Wang L, Yang J, Zhang F, Wu P, Zhao D (2013) Angew Chem Int Ed 52:8151-8155.\u003c/li\u003e\n\u003cli\u003eNagaraj M, Ramalingam S, Murugan C, Aldawood S, Jin J-O, Choi I, Kim M (2022) Environmental Research 212:113273.\u003c/li\u003e\n\u003cli\u003eXu Q, Kuang T, Liu Y, Cai L, Peng X, Sreeprasad TS, Zhao P, Yu Z, Li N (2016) Journal of Materials Chemistry B 4:7204-7219.\u003c/li\u003e\n\u003cli\u003eJing HH, Bardakci F, Akg\u0026ouml;l S, Kusat K, Adnan M, Alam MJ, Gupta R, Sahreen S, Chen Y, Gopinath SC (2023) Journal of Functional Biomaterials 14:27. \u003c/li\u003e\n\u003cli\u003eXu M, Xu S, Yang Z, Shu M, He G, Huang D, Zhang L, Li L, Cui D, Zhang Y (2015) Nanoscale 7:15915-15923.\u003c/li\u003e\n\u003cli\u003eZhao P, Li X, Baryshnikov G, Wu B, \u0026Aring;gren H, Zhang J, Zhu L (2018) Chemical Science 9:1323-1329.\u003c/li\u003e\n\u003cli\u003eLiu Y, Zhou Q, Li J, Lei M, Yan X (2016) Sensors and Actuators B: Chemical 237:597-604.\u003c/li\u003e\n\u003cli\u003eWang C, Yang M, Shi H, Yao Z, Liu E, Hu X, Guo P, Xue W, Fan J (2022) Dyes and Pigments 204:110431.\u003c/li\u003e\n\u003cli\u003eJin X, Bai H, Ma Y, Li Y, Chen W (2023) ChemistrySelect 8:e202204852.\u003c/li\u003e\n\u003cli\u003eYang X, Ai L, Yu J, Waterhouse GI, Sui L, Ding J, Zhang B, Yong X, Lu S (2022) Science Bulletin 67:1450-1457.\u003c/li\u003e\n\u003cli\u003eJin J-C, Yu Y, Yan R, Cai S-L, Zhang X-Y, Jiang F-L, Liu Y (2021) ACS Applied Bio Materials 4:4973-4981.\u003c/li\u003e\n\u003cli\u003eKalaiyarasan G, Joseph J, Kumar P (2020) ACS omega 5:22278-22288.\u003c/li\u003e\n\u003cli\u003eLiao J, Cheng Z, Zhou L (2016) ACS Sustainable Chemistry \u0026amp; 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Biomolecular Chemistry 20:1373-1378.\u003c/li\u003e\n\u003cli\u003eXu S, Song K, Li T, Tan B (2015) Journal of Materials Chemistry A 3:1272-1278.\u003c/li\u003e\n\u003cli\u003eKandathil V, Dateer RB, Sasidhar B, Patil SA, Patil SA (2018) Catalysis Letters 148:1562-1578.\u003c/li\u003e\n\u003cli\u003eChatterjee S, Bhattacharya SK (2018) ACS omega 3:12905-12913.\u003c/li\u003e\n\u003cli\u003eMosmann T (1983) Journal of immunological methods 65:55-63.\u003c/li\u003e\n\u003cli\u003eMonks A, Scudiero D, Skehan P, Shoemaker R, Paull K, Vistica D, Hose C, Langley J, Cronise P, Vaigro-Wolff A (1991) JNCI: Journal of the National Cancer Institute 83:757-766.\u003c/li\u003e\n\u003cli\u003eBoobalan T, Sethupathi M, Sengottuvelan N, Kumar P, Balaji P, Guly\u0026aacute;s B, Padmanabhan P, Selvan ST, Arun A (2020) ACS Applied Nano Materials 3:5910-5919.\u003c/li\u003e\n\u003cli\u003eCyril N, George JB, Nair PV, Joseph L, Sunila C, Smitha V, Anila B, Sylas V (2020) Nano-Structures \u0026amp; Nano-Objects 22:100430.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Scheme 1","content":"\u003cp\u003eScheme 1 is available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"catalysis-letters","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Catalysis Letters](https://link.springer.com/journal/10562)","snPcode":"10562","submissionUrl":"https://submission.springernature.com/new-submission/10562/3","title":"Catalysis Letters","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-6170167/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6170167/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eUsing bottle gourd peel and arginine, the hydrothermal sustainable approach was employed to synthesize blue emissive nitrogen-doped carbon quantum dots (NCQD) with a quantum yield of 29.40%. The excitation-dependent action of NCQD led to its choice for the detection of picric acid (PA), bioimaging investigations for MCF-7 (breast cancer) cells, and as an antibacterial agent against \u003cem\u003eStaphylococcus aureus\u003c/em\u003e and \u003cem\u003eKlebsiella pneumonia\u003c/em\u003e bacteria. The limit of detection (LoD) for picric cid was discovered to be 10 nM. Palladium nanoparticles (Pd nanoparticles) were prepared from the synthesized NCQD, where the NCQD served as both a reducing and stabilizing agent for the Pd nanoparticles. Several spectroscopic methods were also used to analyze the nanoparticles. The wide surface area and small Pd nanoparticles make them an ideal catalyst for reducing nitrophenols in aqueous medium and denitrogenative cross-coupling reactions.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e","manuscriptTitle":"Amino acid-assisted carbon quantum dots for bioimaging, Picric acid detection, antibacterial activity, and prefabrication of Pd nanoparticles as a potent nanocatalyst for coupling reactions and reduction of nitrophenols","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-03-17 13:56:34","doi":"10.21203/rs.3.rs-6170167/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-03-31T10:23:31+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-03-22T10:15:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"69967104758164689318719763562917975718","date":"2025-03-15T14:48:15+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"152839596666945662977281007802719021326","date":"2025-03-13T17:22:20+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-03-13T14:07:29+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-03-13T07:08:22+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-03-13T07:07:01+00:00","index":"","fulltext":""},{"type":"submitted","content":"Catalysis Letters","date":"2025-03-06T11:32:18+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"catalysis-letters","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Catalysis Letters](https://link.springer.com/journal/10562)","snPcode":"10562","submissionUrl":"https://submission.springernature.com/new-submission/10562/3","title":"Catalysis Letters","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"e036f689-c8dd-41f1-9ce1-4b8e16bb5eef","owner":[],"postedDate":"March 17th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-05-10T17:53:14+00:00","versionOfRecord":[],"versionCreatedAt":"2025-03-17 13:56:34","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6170167","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6170167","identity":"rs-6170167","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}