Synthesis, characterization, photophysical and DFT studies of (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one, a novel aminochalcone

Synthesis, characterization, photophysical and DFT studies of (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one, a novel aminochalcone | 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 Synthesis, characterization, photophysical and DFT studies of (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one, a novel aminochalcone Pablo Martínez, Neudo Urdaneta, Gustavo Benaím, Nieves Canudas, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7430349/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 28 Nov, 2025 Read the published version in Journal of Fluorescence → Version 1 posted 18 You are reading this latest preprint version Abstract Chalcones constitute a distinct family of compounds with intrinsic fluorescence properties that make them valuable tools for a variety of applications. In this work, a new chalcone core derivative, ( E )-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one, was synthesized via a Claisen–Schmidt condensation reaction and fully characterized by IR, NMR spectroscopy and GC-MS analysis. Also was subsequently subjected to comprehensive photophysical and computational studies. For the photophysical characterization, the molar absorptivity coefficients and fluorescence quantum yields in methanol, acetonitrile, and chloroform were determined, along with an analysis of solvatochromic and solvatofluorochromic effects in different solvents and the assessment of the Stokes shift. The compound exhibited positive solvatochromism and solvatofluorochromism, providing valuable information on its polarity-dependent behavior. Computational analysis based on density functional theory elucidated the energy gaps between the boundary molecular orbitals and the electrostatic potential map, which corresponded to the structure of the compound and the trends observed in the photophysical study. Chalcone DFT Photophysical properties Fluorescence Figures Figure 1 Figure 2 Figure 3 Introduction Due to their wide range of applications [ 1 ], the synthesis of novel fluorescent compounds is the subject of great attention in modern chemistry. Organic compounds that exhibit the property of being photoactive are generally highly conjugated systems [ 2 ], with a high number of π electrons. An example of this type of compound is the chalcone (1,3-diaryl-prop-2-en-1-one) chromophore, which is made up of two benzene rings linked by an α-β-unsaturated ketone core [ 3 ]. Chalcones can be easily synthesized by a Claisen-Schmidt condensation reaction between acetophenones and arylaldehydes or their respective derivatives [ 4 ]. The chalcone backbone acts as a template for the synthesis of a variety of derivatives, offering a broad scope of applications through the specific choice of substituents. Such structural arrangements are generally responsible for intramolecular charge transfer in chalcone derivatives [ 5 ], whereby many of them can be used as fluorescent probes. Chalcone derivatives are abundant in plants, being considered precursors of flavonoids and isoflavonoids [ 6 ]. Photoactive compounds derived from plant extracts and natural products have an additional interest that lies in their biocompatibility, bioavailability and ease of degradation [ 7 ]. In this context, chalcone derivatives pose an area of study of major importance for the generation of new drugs, due to their antimicrobial [ 8 ], anti-inflammatory [ 9 ] and antioxidant [ 10 ] properties in the ground state, directly related to their α-β-unsaturated ketone core. Herein, we report on the synthesis and characterization of ( E )-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-on (Fig. 1 ), a novel chalcone derivative. Compounds with both electron-donating and electron-accepting groups are of interest because their polarized structure can enhance reactivity and modulate properties such as fluorescence. The photophysical properties of the chalcone derivative were studied by experimentally examining the effects of different solvents on its absorption and emission spectra, as well as the determination of parameters like the relative quantum yield. The experimental photophysical characterization was supported by a theoretical approach using DFT calculations to further investigate its molecular structure, frontier orbitals and characteristics of this chalcone derivative. Experimental section Materials, Methods, and Instruments All chemicals were of analytical grade and they were used as received without any further purification. Fourier Transform Infrared (FT-IR) spectra were measured on a Thermo-Scientific® Nicolet iS10 spectrometer. 1 H (400 MHz) and 13 C (125 MHz) Nuclear Magnetic Resonance (NMR) spectra were taken in CDCl 3 on a Bruker® Avance spectrometer at room temperature. Chemical shifts are reported in ppm downfield from tetramethylsilane (TMS) as the internal standard; the coupling constant J is given in Hz. The gas chromatography–mass spectrometry (GC–MS) analyses were conducted in an Agilent 8860 GC Chromatograph coupled to an Agilent 5977C mass spectrometer, equipped with an Agilent HP-5MS fused silica capillary column (30 m × 0.25 mm × 0.25 mm). The temperature of the injector and detector was set at 250°C and mass spectra were obtained with a 70 eV electron impact. The absorption and fluorescence spectra were recorded on a Varian® Cary 50 spectrophotometer and a Hitachi® F-7000 spectrofluorophotometer, respectively. Synthesis of ( E )-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one The compound was synthesized by a previously reported method [ 11 ]. Briefly, NaOH (0.160 g, 4.00mmol) was added to a well stirred solution of 4-aminoacetophenone (0.203 g, 1.50 mmol) and 1-benzyl-1H-pyrrole-2-carbaldehyde (0.278g, 1.5 mmol) in ethanol (10 ml). The reaction mixture was further stirred for 24 h at room temperature. The completeness of the reaction was monitored by thin-layer chromatography on silica plates (using an 8:2 mixture of Hexane: Ethyl acetate as eluent). Ice cold water was added, and the precipitated chalcone was filtered. The obtained yellow crystals were washed with H 2 O and recrystallized from 80% ethanol. Yield: 0.318 g (70%). M.p: 55–57°C. IR (KBr): ν(cm − 1 ) = 3432 (NH), 3233 (N = CH), 1593 (C = O), 1527 (C = C), 1596 (Figure S1 ). 1 H-NMR (CDCl 3 , 300 MHz, δ ppm, J Hz): 1.77 (s, 2H, CH 2 ), 4.12 (s, 2H, NH 2 ), 6.67 (d, 2H, J = 8.4 Hz, 4H, ArH), 6.89 (m, 2H), 7.74 (m, 5H), 7.29 (d, 1H, J = 15.2, COC = CH), 7.76( d,1H,J = 15.2,COC = CH), 7.83 (d, 2H J = 8.7 Hz, 2H, ArH), 7.74 (d, J = 15.3, 1H, COCH = C), 7.91 (d, J = 8.4, 2H, ArH) (Figure S2 ). 13 C NMR (CDCl 3 , 125 MHz): 187.7, 150.7, 137.4, 130.8, 130.7, 130.3, 128.9, 127.7, 126.7, 126.5, 117.5, 113.9, 112.0, 110.0, 50.7 (Figure S3 ). GC-MS (m/z): 302.11 [M + H] + . GC-MS (EI, m/z, % abund.): 302(10), 182(15), 120(40), 91(100), 65(30) (Figure S4 ). Fluorescence quantum yields Coumarin 334 and coumarin 343, both purchased from Aldrich as “synthetic grade” and used without further purification were employed as quantum yield standards dissolved in ethanol. The quantum yields for the studied compounds in three different solvents were calculated using the cross-calibration method described by Williams et al [ 12 ]. To prevent the inner filter effect, the integrated fluorescence intensities of each compound were determined from the emission spectra at different concentrations below 1.00x10 − 5 M and graphed as a function of the measured absorbance at each concentration. The quantum yield was determined as follows: $$\:\varPhi\:Fx=\varPhi\:Fs\:\left(\frac{Gx}{Gs}\right)\left(\frac{{\eta\:x}^{2}}{{\eta\:s}^{2}}\right)\:$$ where ΦFx is the relative fluorescence quantum yield of the sample, ΦFs is the relative fluorescence quantum yield of the standard, Gx is the slope of the integrated fluorescence intensity line as a function of the sample absorbance, Gs is the slope of the integrated fluorescence intensity line as a function of the standard absorbance, ηs is the refractive index of the solvent in which the standard is dissolved and ηx is the refractive index of the solvent in which the sample is dissolved. Computational methods The ground state geometry of the compound was determined by standard DFT. Frontier molecular orbitals and the electrostatic map were also estimated to study the electron density in the compound. All the computational calculations were conducted using the Gaussian 09 program [28] on a personal computer using B3LYP [29] in addition to the 6-31G(d,p) basis set. Results and discussion Modifications on the chalcone backbone have allowed to develop its fluorescent potential, being an example of this the formation of push-pull systems in which π conjugated electrons are present, as well as an electron acceptor group and an electron donor group [ 13 ]. This interaction results in intramolecular charge transfer (ICT) (Figure S5 ), which generates a new molecular orbital. Excitation of the π electrons to this molecular orbital can take place with UV-visible light. During this process, polarization of the molecule occurs and consequently the generation of a dipole moment in the molecule in the excited state [ 14 ]. The synthetized compound can be considered as a push-pull system. Based on the structure of the compound, two possible ICT processes can be derived, from the amino group or the pyrrole moiety acting as donor, and the enone moiety acting as acceptor in both cases (Figure S5 ). The nitrogen atom of the amino group can donate its free electron pair in the para position of the ring and cause a flow of electrons towards the carbonyl, which has the ability to accept charge density. Alternatively, the pyrrole group may act as a donor causing an intramolecular charge transfer to the carbonyl group, which may behave again as an acceptor moiety within the molecule. In the 1 H-NMR spectrum (Figure S2 ), signals corresponding to the protons in the structure of the synthesized chalcone derivative are observed. The upfield signals were assigned to δ = 1.77 ppm and correspond to the hydrogens located on the single sp 3 carbon. The signal corresponding to δ = 4.12ppm is related to the hydrogens in the amino group, since aromatic amines show signals appearing in the range of 3 to 5 ppm. The band observed between 6.67–6.64 ppm is a doublet integrating for 2H, its coupling constant is 8.4 Hz and agrees with the band between 7.83–7.80 ppm, which shares multiplicity, coupling and area. It can then be affirmed that both bands belong to the same aromatic ring and, by its properties, it is a substituted ring in the para position. Typically, for these systems, their spins are coupled and result in a doublet of doublets. Between 7.76–7.71 ppm, there is a doublet that integrates for a proton and has a coupling constant of 15.2 Hz, which shares characteristics with two signals within the multiplet for δ = 7.24 and 7.29 ppm, so these belong to the two hydrogens in the α-β unsaturation adjacent to the carbonyl. Furthermore, because of the high value of this constant, it corresponds to the geometry of the trans or E isomer. In the 13 C-NMR spectrum (Figure S3 ), the signals between 125.7ppm and 151ppm represent the aromatic carbons that were expected to be accounted for. The signal at less than 50.6ppm represents the single sp3 carbon, whereas the signals at 113ppm and 117.5ppm refer to the double bond that is adjacent to the carbonyl. The highest signal at 187ppm represents the carbon of the carbonyl group, due to its high de-shielding. Photophysical properties of the compound were studied through the measurement of absorption and emission spectra. The values of the molar absorptivity coefficients (ε) obtained for this chalcone derivative in chloroform, acetonitrile and methanol indicate the feasibility with which the electronic transition associated with the absorption maximum occurs. The Franck-Condon principle states that transitions π→ π* are favored for geometry-conserving systems and are the most likely, according to the selection rules [ 15 ]. For the three cases evaluated (17997 M − 1 cm − 1 in methanol, 30957 M − 1 cm − 1 in acetonitrile and 23957 M − 1 cm − 1 in chloroform), molar absorptivity coefficients in the order of 10 5 were obtained, which are associated with transitions π → π*. In order to analyze both the solvatochromic and the solvatofluorochromic effects, spectra were recorded in solvents of different polarities (Fig. 2 ). It is apparent that as the polarity of the solvent increases there is a significant redshift of the absorption maxima, suggesting the presence of ICT between the acceptor and donor groups in the molecule (Figure S5 ). Considering that the molecule studied is not especially polar and that its ground state should not be largely stabilized due to the effect of the polarity of the solvent, it could be assumed that the bathochromic displacements described suggest a preferential stabilization of the excited states in polar solvents, making the transition less energetic. The aforementioned results were confirmed when evaluating the solvatofluorochromic effect, in which a marked redshift of the emission peaks was observed with increasing polarity of the solvent. This is related to the gradual stabilization of the excited state, which is inherently more polar than the fundamental state. As the polarity of the solvent increases, the energy difference between the fundamental state and the excited state becomes smaller [ 16 ]. It can be seen that the effect of the solvent is more pronounced in the case of the emission than for the absorption in the compounds, due to the fact that the excited state is more polar and more sensitive to solvent effects. Relevant solvatochromic data are summarized in Table 1 . Table 1 Solvatochromic data for ( E )-1-(4-aminophenyl)-3-(1-benzyl-1 H -pyrrol-2-yl) prop-2-en-1-one. Maximum absorption wavelength (λ a ) Maximum fluorescence emission wavelength (λ f ). The Stokes shift (Δν) is the difference in energy between the absorption and emission maxima and is expressed in wavenumbers (cm⁻¹). Solvent λa (nm) λf (nm) Δν (cm − 1 ) Methanol 394 475 4523 Acetonitrile 382 463 4580 DMSO 1 390 467 4228 Acetone 385 460 4234 Chloroform 388 465 4268 Ethyl acetate 375 443 3882 THF 2 378 438 3835 Diethyl ether 370 427 3608 Toluene 374 418 2815 1 DMSO = dimethyl sulfoxide , 2 THF = tetrahydrofuran. The magnitudes of the observed Stokes displacements are linked to the ability of the solvent to solvate the excited state of the fluorophore [ 17 ]. Larger Stokes shifts were determined for the compound in polar solvents such as acetonitrile or methanol, which are associated with the higher solvating capacity of these solvents. On the other hand, in the case of toluene there is no significant dipole moment capable of generating dipoles that can be reoriented to stabilize the excited state of the molecule. Furthermore, there is a slight decrease in the Stokes shift when switching from an aprotic polar solvent (such as acetonitrile) to a protic polar solvent (methanol). This could be attributed to the formation of hydrogen bonds with the non-bonding electrons of oxygen in the structure of the compound. The behavior of push-pull systems in the excited state is generally driven by an ICT process, thus making their behavior strongly dependent on the solvent and as a result the fluorescence observed in polar solvents shows significant Stokes shifts. The values for the fluorescence quantum yield provide insight into the photophysical properties of an unknown fluorescent molecule. The relative quantum fluorescence yields for compounds in chloroform, acetonitrile and methanol are presented in Table 2 . Overall, the fluorescence quantum yield values were low in all solvents, suggesting that the radiative deactivation of the singlet excited state is in competition with other more favored deactivation pathways. Specifically, the lowest value was obtained when methanol was used as the solvent, which is possibly the result of hydrogen bonding interactions. It has been shown that intermolecular hydrogen bonding interactions between solute and solvent molecules facilitate non-radiative processes, thus decreasing fluorescence [ 18 ]. Table 2 Estimated relative fluorescence quantum yields of ( E )-1-(4-aminophenyl)-3-(1-benzyl-1 H -pyrrol-2-yl) prop-2-en-1-one in solvents of different polarity. Solvent Relative fluorescence quantum yield Methanol 0.012 ± 0.001 Acetonitrile 0.061 ± 0.004 Chloroform 0.098 ± 0.007 However, it is worth noting that the highest quantum yields were obtained in chloroform, which might indicate that the presence of chlorine atoms in the solvent may lead to a slightly more efficient radiative deactivation of the excited state by the fluorescence pathway [ 19 ]. Compared to chloroform, there is a decrease in the quantum yield values in acetonitrile and methanol. In the case of acetonitrile, this fact could be explained by a quenching of the fluorescence due to the high ICT related to the push-pull effect present in the molecules, which causes an increase in the non-radiative relaxation rate of the excited state [ 20 ]. Moreover, the formation of hydrogen bonds with molecules like chalcones is a very efficient fluorescence quencher, which possibly accounts for the low quantum yield value obtained in a polar protic solvent such as methanol. To gain a more accurate insight into the electronic structures of the compounds, DFT calculations were carried out. The highest occupied molecule orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy level diagram provides a quantified description of the electronic structure and the excitation properties. The HOMO and LUMO orbitals of the compound determined for the optimized structure are shown in Fig. 3 , where the HOMO is located in the donor region and the LUMO in the acceptor region. Particularly, the excitation of HOMO-LUMO can be attributed to an ICT transition from donor to acceptor as a result of the push-pull nature of the molecule. The quantum fluorescence yield decreases as the energy gap between the HOMO and LUMO orbitals increases. This suggests an enhancement of the transition from the ground state of the molecule to the first excited state, subsequently favoring the emission of fluorescence. This indicates an improvement in the transition from the ground state of the molecule to the first excited state, subsequently favoring the emission of fluorescence. The structures of the compound are in agreement with the computed electrostatic potential maps, where there is a greater distribution of electronic charge in the regions illustrated by the black circles, while in the regions illustrated by the white circles there is a poor distribution of the electronic charge (Fig. 3 ). It is possible that the efficiency in the radiative emission of this type of chalcone derivatives is related to the fact that their electronic density is distributed towards the nucleus of the molecule, due to the influence of the electron donor groups attached to their aromatic rings. Despite its relatively low quantum yield, this fluorescent chalcone derivative offers promising structural characteristics as a push-pull system that warrant further exploration. Its unique structural features and emission properties suggest potential applications where fluorescence intensity is not the primary requirement, such as turn-on fluorescent sensors. Additionally, the chalcone scaffold is highly tunable, allowing for modifications that could enhance its photophysical properties. Conclusions In the present study, the synthesis, characterization, photophysical and computational studies on a novel chalcone derivative, ( E )-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one are reported. The results show that the compound exhibited positive solvatochromism and solvatofluorochromism associated with dipole-dipole interactions with the solvent, which stabilizes the ground and excited states. The Stokes shifts obtained for the chalcone derivative indicate that the difference between the ground state and the excited state from which emission occurs is greater for apolar and polar aprotic solvents than for polar protic solvents. The fluorescence quantum yield values for the compound were generally low, suggesting that this is not the primary deactivation mechanism. The energy gaps of the frontier molecular orbitals and the electrostatic potential map of the compound determined by computational studies may be indicative of radiative relaxation mechanisms, which could explain the fluorescence emission observed despite the low fluorescence quantum yield values. Declarations Competing Interests The authors have no relevant financial or non-financial interests to disclose. Funding This work was supported by FONACIT, Caracas, Venezuela (grant numbers 20230PGP99 to JB and GB, and 2024PGP315 to GB), Decanato de Investigación y Desarrollo, Universidad Simón Bolívar, Caracas, Venezuela (to NU), and CDCH-UCV Group Research Project 2025 (to GB). Author Contribution Pablo Martínez and José Bubis conceived and designed the study. Neudo Urdaneta synthesized and spectroscopically characterized the compound. Pablo Martínez performed the experiments and analyzed the data. Gustavo Benaím and Nieves Canudas assisted with the fluorescence analyses. Pablo Martínez and José Bubis wrote the manuscript, and all authors commented on the preliminary version. All authors read and approved the final manuscript. Acknowledgments This research was supported by FONACIT, Caracas, Venezuela (grant numbers 20230PGP99 to JB and GB, and 2024PGP315 to GB), Decanato de Investigación y Desarrollo, Universidad Simón Bolívar, Caracas, Venezuela (to NU), and CDCH-UCV Group Research Project 2025 (to GB). Data Availability All generated data is included either in the main content or in the supplementary material of the manuscript. If required, specific datasets are available from the corresponding authors on request. References Sung D, Lee L (2023) Natural-product-based fluorescent probes: recent advances and application. RSC Med Chem 14(3):412–432. 10.1039/d2md00376g Jaswal S, Kumar J (2020) Review on fluorescent donor–acceptor conjugated system as molecular probes. Mater. Today Proc. , 26, 566–580. 10.1016/j.matpr.2019.12.161 Shalaby M, Rizk S, Fahim A (2023) Synthesis, reactions and application of chalcones: a systematic review. 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IR spectrum for (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one. FigureS2.tif Figure S2. 1H NMR spectrum for (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one (A). Regions of the spectrum were expanded to enhance the visibility and resolution of individual peaks or multiplets (B). FigureS3.tif Figure S3. 13C NMR spectrum for (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one (A). Regions of the spectrum were expanded to enhance the visibility and resolution of individual peaks or multiplets (B). FigureS4.tif Figure S4. GC-MS spectrum for (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one. FigureS5.tif Figure S5. Two potential intramolecular charge transfer processes for (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one, from the amino group (A) or the pyrrole moiety (B) acting as donor, and the enone moiety acting as acceptor in both cases. Cite Share Download PDF Status: Published Journal Publication published 28 Nov, 2025 Read the published version in Journal of Fluorescence → Version 1 posted Editorial decision: Revision requested 23 Sep, 2025 Reviews received at journal 20 Sep, 2025 Reviews received at journal 18 Sep, 2025 Reviews received at journal 18 Sep, 2025 Reviews received at journal 17 Sep, 2025 Reviews received at journal 15 Sep, 2025 Reviews received at journal 13 Sep, 2025 Reviewers agreed at journal 10 Sep, 2025 Reviewers agreed at journal 09 Sep, 2025 Reviewers agreed at journal 09 Sep, 2025 Reviewers agreed at journal 08 Sep, 2025 Reviewers agreed at journal 08 Sep, 2025 Reviewers agreed at journal 08 Sep, 2025 Reviewers agreed at journal 08 Sep, 2025 Reviewers invited by journal 08 Sep, 2025 Editor assigned by journal 26 Aug, 2025 Submission checks completed at journal 26 Aug, 2025 First submitted to journal 21 Aug, 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. 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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-7430349","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":514662620,"identity":"e26ce9bc-e764-4a3a-bd33-1e7ec6bddbb4","order_by":0,"name":"Pablo Martínez","email":"","orcid":"","institution":"Universidad Simón Bolívar","correspondingAuthor":false,"prefix":"","firstName":"Pablo","middleName":"","lastName":"Martínez","suffix":""},{"id":514662621,"identity":"377e3e56-18af-4b40-ba91-47c0b4515cbf","order_by":1,"name":"Neudo Urdaneta","email":"","orcid":"","institution":"Universidad Simón Bolívar","correspondingAuthor":false,"prefix":"","firstName":"Neudo","middleName":"","lastName":"Urdaneta","suffix":""},{"id":514662622,"identity":"05ce9f5d-f55e-4f78-a235-c9238444fde6","order_by":2,"name":"Gustavo Benaím","email":"","orcid":"","institution":"Fundación Estudios Avanzados IDEA","correspondingAuthor":false,"prefix":"","firstName":"Gustavo","middleName":"","lastName":"Benaím","suffix":""},{"id":514662623,"identity":"58a2517a-c87d-4326-bf0c-889ebecf455b","order_by":3,"name":"Nieves Canudas","email":"","orcid":"","institution":"Universidad Simón Bolívar","correspondingAuthor":false,"prefix":"","firstName":"Nieves","middleName":"","lastName":"Canudas","suffix":""},{"id":514662624,"identity":"43f6b1f3-60ca-4678-a7d0-1cb75f2e5084","order_by":4,"name":"José Bubis","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAq0lEQVRIiWNgGAWjYBACxhkMbAwJDDYMDBIkakkjQQtQJRuQPEyCFubZPWYPHvw5nzh/dgObxAeiHDbnjLlBYtvtxA13DrBJziBKy4wcM4nEBqAWiQRmYx6itST8OZc4fwZQyx/itbAdSGy4kcD4mBgdQL8cKwf6Jdl4w52DjQ97iNFiOLt528Mff+xk589uPnDgB1FaGhAWNuBUhQLkiVM2CkbBKBgFIxoAAOooNkhevu58AAAAAElFTkSuQmCC","orcid":"","institution":"Fundación Estudios Avanzados IDEA","correspondingAuthor":true,"prefix":"","firstName":"José","middleName":"","lastName":"Bubis","suffix":""}],"badges":[],"createdAt":"2025-08-22 03:38:12","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7430349/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7430349/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10895-025-04645-9","type":"published","date":"2025-11-28T15:58:45+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":91459641,"identity":"a4c28c85-d967-4d71-abfe-f0f10f61eddd","added_by":"auto","created_at":"2025-09-16 16:55:23","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":28522,"visible":true,"origin":"","legend":"\u003cp\u003eChemical structure of\u003cstrong\u003e \u003c/strong\u003e(\u003cem\u003eE\u003c/em\u003e)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-7430349/v1/a382eb9582559eee3ecf7fa9.png"},{"id":91459643,"identity":"f0550b3a-513c-40a6-bb24-26788ea07740","added_by":"auto","created_at":"2025-09-16 16:55:23","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":134779,"visible":true,"origin":"","legend":"\u003cp\u003eUV-Vis absorption (\u003cstrong\u003eA\u003c/strong\u003e) and fluorescence (\u003cstrong\u003eB\u003c/strong\u003e) spectra of (\u003cem\u003eE\u003c/em\u003e)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one in different solvents. THF = tetrahydrofuran, DMSO = \u003cem\u003edimethyl sulfoxide\u003c/em\u003e.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-7430349/v1/d81679399372a8e8f6d1618e.png"},{"id":91460340,"identity":"73a3cc66-0ccc-40f9-84ee-7ba41e09fa90","added_by":"auto","created_at":"2025-09-16 17:03:23","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":152946,"visible":true,"origin":"","legend":"\u003cp\u003ePlots of frontier molecular orbitals and electrostatic potential map of (\u003cem\u003eE\u003c/em\u003e)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one. Frontier molecular orbitals show where electrons are located and available for reaction; high electron density in HOMO, and high electron deficiency in LUMO. Electrostatic potential maps illustrate charge distribution across the molecular surface. The black circles show a greater distribution of electronic charge or negative electrostatic potential, and the white circles indicate a poor distribution of the electronic charge or positive electrostatic potential, highlighting areas for electrophilic or nucleophilic attack, respectively.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-7430349/v1/1967034c9e0e7a9d669b48be.png"},{"id":97179733,"identity":"e818a1c9-af46-46e5-9b3b-c847d9500e73","added_by":"auto","created_at":"2025-12-01 16:16:49","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":939829,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7430349/v1/119720fe-8a14-4696-bb39-6a3a4308eb44.pdf"},{"id":91459644,"identity":"4cea4ddb-0d80-4274-8650-af41c64705d2","added_by":"auto","created_at":"2025-09-16 16:55:23","extension":"tif","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":153650,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure S1. \u003c/strong\u003eIR spectrum for (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one.\u003c/p\u003e","description":"","filename":"FigureS1.tif","url":"https://assets-eu.researchsquare.com/files/rs-7430349/v1/a51945635f60d16311a5c84a.tif"},{"id":91459645,"identity":"c2557208-56f1-4f54-b9ff-c4d216e2f9c1","added_by":"auto","created_at":"2025-09-16 16:55:23","extension":"tif","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":141892,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure S2. \u003c/strong\u003e1H NMR spectrum for (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one (\u003cstrong\u003eA\u003c/strong\u003e). Regions of the spectrum were expanded to enhance the visibility and resolution of individual peaks or multiplets (\u003cstrong\u003eB\u003c/strong\u003e).\u003c/p\u003e","description":"","filename":"FigureS2.tif","url":"https://assets-eu.researchsquare.com/files/rs-7430349/v1/3fc046488ef42a04d3b8ca73.tif"},{"id":91460347,"identity":"a3eca435-fe68-46a1-b8ad-db7158b28617","added_by":"auto","created_at":"2025-09-16 17:03:23","extension":"tif","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":123726,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure S3. \u003c/strong\u003e13C NMR spectrum for (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one (A). Regions of the spectrum were expanded to enhance the visibility and resolution of individual peaks or multiplets (\u003cstrong\u003eB\u003c/strong\u003e).\u003c/p\u003e","description":"","filename":"FigureS3.tif","url":"https://assets-eu.researchsquare.com/files/rs-7430349/v1/8f8e5246e32e05835c7937c2.tif"},{"id":91461164,"identity":"ba974663-9b15-4412-a273-5e61b2c3a648","added_by":"auto","created_at":"2025-09-16 17:11:23","extension":"tif","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":94676,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure S4.\u003c/strong\u003e GC-MS spectrum for (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one.\u003c/p\u003e","description":"","filename":"FigureS4.tif","url":"https://assets-eu.researchsquare.com/files/rs-7430349/v1/5c8d8efccb78ecff39f74120.tif"},{"id":91816629,"identity":"cb4aa718-82f2-4478-bbbb-2afd952eb913","added_by":"auto","created_at":"2025-09-22 06:52:18","extension":"tif","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":74444,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure S5. \u003c/strong\u003eTwo potential intramolecular charge transfer processes for (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one, from the amino group (\u003cstrong\u003eA\u003c/strong\u003e) or the pyrrole moiety (\u003cstrong\u003eB\u003c/strong\u003e) acting as donor, and the enone moiety acting as acceptor in both cases.\u003c/p\u003e","description":"","filename":"FigureS5.tif","url":"https://assets-eu.researchsquare.com/files/rs-7430349/v1/a895a36583352e9a263eb5da.tif"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eSynthesis, characterization, photophysical and DFT studies of (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one, a novel aminochalcone\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDue to their wide range of applications [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], the synthesis of novel fluorescent compounds is the subject of great attention in modern chemistry. Organic compounds that exhibit the property of being photoactive are generally highly conjugated systems [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], with a high number of π electrons. An example of this type of compound is the chalcone (1,3-diaryl-prop-2-en-1-one) chromophore, which is made up of two benzene rings linked by an α-β-unsaturated ketone core [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Chalcones can be easily synthesized by a Claisen-Schmidt condensation reaction between acetophenones and arylaldehydes or their respective derivatives [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe chalcone backbone acts as a template for the synthesis of a variety of derivatives, offering a broad scope of applications through the specific choice of substituents. Such structural arrangements are generally responsible for intramolecular charge transfer in chalcone derivatives [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], whereby many of them can be used as fluorescent probes.\u003c/p\u003e\u003cp\u003eChalcone derivatives are abundant in plants, being considered precursors of flavonoids and isoflavonoids [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Photoactive compounds derived from plant extracts and natural products have an additional interest that lies in their biocompatibility, bioavailability and ease of degradation [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. In this context, chalcone derivatives pose an area of study of major importance for the generation of new drugs, due to their antimicrobial [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], anti-inflammatory [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] and antioxidant [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] properties in the ground state, directly related to their α-β-unsaturated ketone core. Herein, we report on the synthesis and characterization of (\u003cem\u003eE\u003c/em\u003e)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-on (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), a novel chalcone derivative. Compounds with both electron-donating and electron-accepting groups are of interest because their polarized structure can enhance reactivity and modulate properties such as fluorescence. The photophysical properties of the chalcone derivative were studied by experimentally examining the effects of different solvents on its absorption and emission spectra, as well as the determination of parameters like the relative quantum yield. The experimental photophysical characterization was supported by a theoretical approach using DFT calculations to further investigate its molecular structure, frontier orbitals and characteristics of this chalcone derivative.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e"},{"header":"Experimental section","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eMaterials, Methods, and Instruments\u003c/h2\u003e\u003cp\u003eAll chemicals were of analytical grade and they were used as received without any further purification. Fourier Transform Infrared (FT-IR) spectra were measured on a Thermo-Scientific\u0026reg; Nicolet iS10 spectrometer. \u003csup\u003e1\u003c/sup\u003eH (400 MHz) and \u003csup\u003e13\u003c/sup\u003eC (125 MHz) Nuclear Magnetic Resonance (NMR) spectra were taken in CDCl\u003csub\u003e3\u003c/sub\u003e on a Bruker\u0026reg; Avance spectrometer at room temperature. Chemical shifts are reported in ppm downfield from tetramethylsilane (TMS) as the internal standard; the coupling constant J is given in Hz. The gas chromatography\u0026ndash;mass spectrometry (GC\u0026ndash;MS) analyses were conducted in an Agilent 8860 GC Chromatograph coupled to an Agilent 5977C mass spectrometer, equipped with an Agilent HP-5MS fused silica capillary column (30 m \u0026times; 0.25 mm \u0026times; 0.25 mm). The temperature of the injector and detector was set at 250\u0026deg;C and mass spectra were obtained with a 70 eV electron impact. The absorption and fluorescence spectra were recorded on a Varian\u0026reg; Cary 50 spectrophotometer and a Hitachi\u0026reg; F-7000 spectrofluorophotometer, respectively.\u003c/p\u003e\u003cp\u003e\u003cb\u003eSynthesis of (\u003c/b\u003e\u003cb\u003eE\u003c/b\u003e\u003cb\u003e)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe compound was synthesized by a previously reported method [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Briefly, NaOH (0.160 g, 4.00mmol) was added to a well stirred solution of 4-aminoacetophenone (0.203 g, 1.50 mmol) and 1-benzyl-1H-pyrrole-2-carbaldehyde (0.278g, 1.5 mmol) in ethanol (10 ml). The reaction mixture was further stirred for 24 h at room temperature. The completeness of the reaction was monitored by thin-layer chromatography on silica plates (using an 8:2 mixture of Hexane: Ethyl acetate as eluent). Ice cold water was added, and the precipitated chalcone was filtered. The obtained yellow crystals were washed with H\u003csub\u003e2\u003c/sub\u003eO and recrystallized from 80% ethanol. Yield: 0.318 g (70%). M.p: 55\u0026ndash;57\u0026deg;C. IR (KBr): ν(cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u0026thinsp;=\u0026thinsp;3432 (NH), 3233 (N\u0026thinsp;=\u0026thinsp;CH), 1593 (C\u0026thinsp;=\u0026thinsp;O), 1527 (C\u0026thinsp;=\u0026thinsp;C), 1596 (Figure \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e). \u003csup\u003e1\u003c/sup\u003e H-NMR (CDCl\u003csub\u003e3\u003c/sub\u003e, 300 MHz, δ ppm, J Hz): 1.77 (s, 2H, CH\u003csub\u003e2\u003c/sub\u003e), 4.12 (s, 2H, NH\u003csub\u003e2\u003c/sub\u003e), 6.67 (d, 2H, J\u0026thinsp;=\u0026thinsp;8.4 Hz, 4H, ArH), 6.89 (m, 2H), 7.74 (m, 5H), 7.29 (d, 1H, J\u0026thinsp;=\u0026thinsp;15.2, COC\u0026thinsp;=\u0026thinsp;CH), 7.76( d,1H,J\u0026thinsp;=\u0026thinsp;15.2,COC\u0026thinsp;=\u0026thinsp;CH), 7.83 (d, 2H J\u0026thinsp;=\u0026thinsp;8.7 Hz, 2H, ArH), 7.74 (d, J\u0026thinsp;=\u0026thinsp;15.3, 1H, COCH\u0026thinsp;=\u0026thinsp;C), 7.91 (d, J\u0026thinsp;=\u0026thinsp;8.4, 2H, ArH) (Figure \u003cspan refid=\"MOESM2\" class=\"InternalRef\"\u003eS2\u003c/span\u003e). \u003csup\u003e13\u003c/sup\u003eC NMR (CDCl\u003csub\u003e3\u003c/sub\u003e, 125 MHz): 187.7, 150.7, 137.4, 130.8, 130.7, 130.3, 128.9, 127.7, 126.7, 126.5, 117.5, 113.9, 112.0, 110.0, 50.7 (Figure \u003cspan refid=\"MOESM3\" class=\"InternalRef\"\u003eS3\u003c/span\u003e). GC-MS (m/z): 302.11 [M\u0026thinsp;+\u0026thinsp;H]\u003csup\u003e+\u003c/sup\u003e. GC-MS (EI, m/z, % abund.): 302(10), 182(15), 120(40), 91(100), 65(30) (Figure \u003cspan refid=\"MOESM4\" class=\"InternalRef\"\u003eS4\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eFluorescence quantum yields\u003c/h3\u003e\n\u003cp\u003eCoumarin 334 and coumarin 343, both purchased from Aldrich as \u0026ldquo;synthetic grade\u0026rdquo; and used without further purification were employed as quantum yield standards dissolved in ethanol. The quantum yields for the studied compounds in three different solvents were calculated using the cross-calibration method described by Williams et al [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. To prevent the inner filter effect, the integrated fluorescence intensities of each compound were determined from the emission spectra at different concentrations below 1.00x10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e M and graphed as a function of the measured absorbance at each concentration. The quantum yield was determined as follows:\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\:\\varPhi\\:Fx=\\varPhi\\:Fs\\:\\left(\\frac{Gx}{Gs}\\right)\\left(\\frac{{\\eta\\:x}^{2}}{{\\eta\\:s}^{2}}\\right)\\:$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ewhere ΦFx is the relative fluorescence quantum yield of the sample, ΦFs is the relative fluorescence quantum yield of the standard, Gx is the slope of the integrated fluorescence intensity line as a function of the sample absorbance, Gs is the slope of the integrated fluorescence intensity line as a function of the standard absorbance, ηs is the refractive index of the solvent in which the standard is dissolved and ηx is the refractive index of the solvent in which the sample is dissolved.\u003c/p\u003e\n\u003ch3\u003eComputational methods\u003c/h3\u003e\n\u003cp\u003eThe ground state geometry of the compound was determined by standard DFT. Frontier molecular orbitals and the electrostatic map were also estimated to study the electron density in the compound. All the computational calculations were conducted using the Gaussian 09 program [28] on a personal computer using B3LYP [29] in addition to the 6-31G(d,p) basis set.\u003c/p\u003e"},{"header":"Results and discussion","content":"\u003cp\u003eModifications on the chalcone backbone have allowed to develop its fluorescent potential, being an example of this the formation of push-pull systems in which π conjugated electrons are present, as well as an electron acceptor group and an electron donor group [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. This interaction results in intramolecular charge transfer (ICT) (Figure \u003cspan refid=\"MOESM5\" class=\"InternalRef\"\u003eS5\u003c/span\u003e), which generates a new molecular orbital. Excitation of the π electrons to this molecular orbital can take place with UV-visible light. During this process, polarization of the molecule occurs and consequently the generation of a dipole moment in the molecule in the excited state [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe synthetized compound can be considered as a push-pull system. Based on the structure of the compound, two possible ICT processes can be derived, from the amino group or the pyrrole moiety acting as donor, and the enone moiety acting as acceptor in both cases (Figure \u003cspan refid=\"MOESM5\" class=\"InternalRef\"\u003eS5\u003c/span\u003e). The nitrogen atom of the amino group can donate its free electron pair in the para position of the ring and cause a flow of electrons towards the carbonyl, which has the ability to accept charge density. Alternatively, the pyrrole group may act as a donor causing an intramolecular charge transfer to the carbonyl group, which may behave again as an acceptor moiety within the molecule.\u003c/p\u003e\u003cp\u003eIn the \u003csup\u003e1\u003c/sup\u003eH-NMR spectrum (Figure \u003cspan refid=\"MOESM2\" class=\"InternalRef\"\u003eS2\u003c/span\u003e), signals corresponding to the protons in the structure of the synthesized chalcone derivative are observed. The upfield signals were assigned to δ\u0026thinsp;=\u0026thinsp;1.77 ppm and correspond to the hydrogens located on the single sp\u003csup\u003e3\u003c/sup\u003e carbon. The signal corresponding to δ\u0026thinsp;=\u0026thinsp;4.12ppm is related to the hydrogens in the amino group, since aromatic amines show signals appearing in the range of 3 to 5 ppm. The band observed between 6.67\u0026ndash;6.64 ppm is a doublet integrating for 2H, its coupling constant is 8.4 Hz and agrees with the band between 7.83\u0026ndash;7.80 ppm, which shares multiplicity, coupling and area. It can then be affirmed that both bands belong to the same aromatic ring and, by its properties, it is a substituted ring in the para position. Typically, for these systems, their spins are coupled and result in a doublet of doublets.\u003c/p\u003e\u003cp\u003eBetween 7.76\u0026ndash;7.71 ppm, there is a doublet that integrates for a proton and has a coupling constant of 15.2 Hz, which shares characteristics with two signals within the multiplet for δ\u0026thinsp;=\u0026thinsp;7.24 and 7.29 ppm, so these belong to the two hydrogens in the α-β unsaturation adjacent to the carbonyl. Furthermore, because of the high value of this constant, it corresponds to the geometry of the trans or \u003cem\u003eE\u003c/em\u003e isomer.\u003c/p\u003e\u003cp\u003eIn the \u003csup\u003e13\u003c/sup\u003eC-NMR spectrum (Figure \u003cspan refid=\"MOESM3\" class=\"InternalRef\"\u003eS3\u003c/span\u003e), the signals between 125.7ppm and 151ppm represent the aromatic carbons that were expected to be accounted for. The signal at less than 50.6ppm represents the single sp3 carbon, whereas the signals at 113ppm and 117.5ppm refer to the double bond that is adjacent to the carbonyl. The highest signal at 187ppm represents the carbon of the carbonyl group, due to its high de-shielding.\u003c/p\u003e\u003cp\u003ePhotophysical properties of the compound were studied through the measurement of absorption and emission spectra. The values of the molar absorptivity coefficients (ε) obtained for this chalcone derivative in chloroform, acetonitrile and methanol indicate the feasibility with which the electronic transition associated with the absorption maximum occurs. The Franck-Condon principle states that transitions π\u0026rarr; π* are favored for geometry-conserving systems and are the most likely, according to the selection rules [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. For the three cases evaluated (17997 M\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003ecm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in methanol, 30957 M\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003ecm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in acetonitrile and 23957 M\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003ecm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in chloroform), molar absorptivity coefficients in the order of 10\u003csup\u003e5\u003c/sup\u003e were obtained, which are associated with transitions π \u0026rarr; π*.\u003c/p\u003e\u003cp\u003eIn order to analyze both the solvatochromic and the solvatofluorochromic effects, spectra were recorded in solvents of different polarities (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eIt is apparent that as the polarity of the solvent increases there is a significant redshift of the absorption maxima, suggesting the presence of ICT between the acceptor and donor groups in the molecule (Figure \u003cspan refid=\"MOESM5\" class=\"InternalRef\"\u003eS5\u003c/span\u003e). Considering that the molecule studied is not especially polar and that its ground state should not be largely stabilized due to the effect of the polarity of the solvent, it could be assumed that the bathochromic displacements described suggest a preferential stabilization of the excited states in polar solvents, making the transition less energetic.\u003c/p\u003e\u003cp\u003eThe aforementioned results were confirmed when evaluating the solvatofluorochromic effect, in which a marked redshift of the emission peaks was observed with increasing polarity of the solvent. This is related to the gradual stabilization of the excited state, which is inherently more polar than the fundamental state. As the polarity of the solvent increases, the energy difference between the fundamental state and the excited state becomes smaller [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. It can be seen that the effect of the solvent is more pronounced in the case of the emission than for the absorption in the compounds, due to the fact that the excited state is more polar and more sensitive to solvent effects. Relevant solvatochromic data are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eSolvatochromic data for (\u003cem\u003eE\u003c/em\u003e)-1-(4-aminophenyl)-3-(1-benzyl-1\u003cem\u003eH\u003c/em\u003e-pyrrol-2-yl) prop-2-en-1-one. Maximum absorption wavelength (λ\u003csub\u003ea\u003c/sub\u003e) Maximum fluorescence emission wavelength (λ\u003csub\u003ef\u003c/sub\u003e). The Stokes shift (Δν) is the difference in energy between the absorption and emission maxima and is expressed in wavenumbers (cm⁻\u0026sup1;).\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSolvent\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eλa (nm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eλf (nm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eΔν (cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMethanol\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e394\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e475\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e4523\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAcetonitrile\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e382\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e463\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e4580\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDMSO \u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e390\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e467\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e4228\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAcetone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e385\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e460\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e4234\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eChloroform\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e388\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e465\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e4268\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eEthyl acetate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e375\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e443\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e3882\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTHF \u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e378\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e438\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e3835\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDiethyl ether\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e370\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e427\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e3608\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eToluene\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e374\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e418\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e2815\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003csup\u003e1\u003c/sup\u003e DMSO\u0026thinsp;=\u0026thinsp;\u003cem\u003edimethyl sulfoxide\u003c/em\u003e, \u003csup\u003e2\u003c/sup\u003e THF\u0026thinsp;=\u0026thinsp;tetrahydrofuran.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe magnitudes of the observed Stokes displacements are linked to the ability of the solvent to solvate the excited state of the fluorophore [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Larger Stokes shifts were determined for the compound in polar solvents such as acetonitrile or methanol, which are associated with the higher solvating capacity of these solvents. On the other hand, in the case of toluene there is no significant dipole moment capable of generating dipoles that can be reoriented to stabilize the excited state of the molecule. Furthermore, there is a slight decrease in the Stokes shift when switching from an aprotic polar solvent (such as acetonitrile) to a protic polar solvent (methanol). This could be attributed to the formation of hydrogen bonds with the non-bonding electrons of oxygen in the structure of the compound.\u003c/p\u003e\u003cp\u003eThe behavior of push-pull systems in the excited state is generally driven by an ICT process, thus making their behavior strongly dependent on the solvent and as a result the fluorescence observed in polar solvents shows significant Stokes shifts.\u003c/p\u003e\u003cp\u003eThe values for the fluorescence quantum yield provide insight into the photophysical properties of an unknown fluorescent molecule. The relative quantum fluorescence yields for compounds in chloroform, acetonitrile and methanol are presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Overall, the fluorescence quantum yield values were low in all solvents, suggesting that the radiative deactivation of the singlet excited state is in competition with other more favored deactivation pathways. Specifically, the lowest value was obtained when methanol was used as the solvent, which is possibly the result of hydrogen bonding interactions. It has been shown that intermolecular hydrogen bonding interactions between solute and solvent molecules facilitate non-radiative processes, thus decreasing fluorescence [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEstimated relative fluorescence quantum yields of (\u003cem\u003eE\u003c/em\u003e)-1-(4-aminophenyl)-3-(1-benzyl-1\u003cem\u003eH\u003c/em\u003e-pyrrol-2-yl) prop-2-en-1-one in solvents of different polarity.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"2\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSolvent\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRelative fluorescence quantum yield\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMethanol\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e0.012\u0026thinsp;\u0026plusmn;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAcetonitrile\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e0.061\u0026thinsp;\u0026plusmn;\u0026thinsp;0.004\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eChloroform\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e0.098 \u0026plusmn; 0.007\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eHowever, it is worth noting that the highest quantum yields were obtained in chloroform, which might indicate that the presence of chlorine atoms in the solvent may lead to a slightly more efficient radiative deactivation of the excited state by the fluorescence pathway [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eCompared to chloroform, there is a decrease in the quantum yield values in acetonitrile and methanol. In the case of acetonitrile, this fact could be explained by a quenching of the fluorescence due to the high ICT related to the push-pull effect present in the molecules, which causes an increase in the non-radiative relaxation rate of the excited state [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Moreover, the formation of hydrogen bonds with molecules like chalcones is a very efficient fluorescence quencher, which possibly accounts for the low quantum yield value obtained in a polar protic solvent such as methanol.\u003c/p\u003e\u003cp\u003eTo gain a more accurate insight into the electronic structures of the compounds, DFT calculations were carried out. The highest occupied molecule orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy level diagram provides a quantified description of the electronic structure and the excitation properties. The HOMO and LUMO orbitals of the compound determined for the optimized structure are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e3\u003c/span\u003e, where the HOMO is located in the donor region and the LUMO in the acceptor region. Particularly, the excitation of HOMO-LUMO can be attributed to an ICT transition from donor to acceptor as a result of the push-pull nature of the molecule.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe quantum fluorescence yield decreases as the energy gap between the HOMO and LUMO orbitals increases. This suggests an enhancement of the transition from the ground state of the molecule to the first excited state, subsequently favoring the emission of fluorescence. This indicates an improvement in the transition from the ground state of the molecule to the first excited state, subsequently favoring the emission of fluorescence.\u003c/p\u003e\u003cp\u003eThe structures of the compound are in agreement with the computed electrostatic potential maps, where there is a greater distribution of electronic charge in the regions illustrated by the black circles, while in the regions illustrated by the white circles there is a poor distribution of the electronic charge (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e3\u003c/span\u003e). It is possible that the efficiency in the radiative emission of this type of chalcone derivatives is related to the fact that their electronic density is distributed towards the nucleus of the molecule, due to the influence of the electron donor groups attached to their aromatic rings.\u003c/p\u003e\u003cp\u003eDespite its relatively low quantum yield, this fluorescent chalcone derivative offers promising structural characteristics as a push-pull system that warrant further exploration. Its unique structural features and emission properties suggest potential applications where fluorescence intensity is not the primary requirement, such as turn-on fluorescent sensors. Additionally, the chalcone scaffold is highly tunable, allowing for modifications that could enhance its photophysical properties.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn the present study, the synthesis, characterization, photophysical and computational studies on a novel chalcone derivative, (\u003cem\u003eE\u003c/em\u003e)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one are reported. The results show that the compound exhibited positive solvatochromism and solvatofluorochromism associated with dipole-dipole interactions with the solvent, which stabilizes the ground and excited states. The Stokes shifts obtained for the chalcone derivative indicate that the difference between the ground state and the excited state from which emission occurs is greater for apolar and polar aprotic solvents than for polar protic solvents. The fluorescence quantum yield values for the compound were generally low, suggesting that this is not the primary deactivation mechanism. The energy gaps of the frontier molecular orbitals and the electrostatic potential map of the compound determined by computational studies may be indicative of radiative relaxation mechanisms, which could explain the fluorescence emission observed despite the low fluorescence quantum yield values.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eCompeting Interests\u003c/h2\u003e\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e\u003cp\u003eThis work was supported by FONACIT, Caracas, Venezuela (grant numbers 20230PGP99 to JB and GB, and 2024PGP315 to GB), Decanato de Investigaci\u0026oacute;n y Desarrollo, Universidad Sim\u0026oacute;n Bol\u0026iacute;var, Caracas, Venezuela (to NU), and CDCH-UCV Group Research Project 2025 (to GB).\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003ePablo Mart\u0026iacute;nez and Jos\u0026eacute; Bubis conceived and designed the study. Neudo Urdaneta synthesized and spectroscopically characterized the compound. Pablo Mart\u0026iacute;nez performed the experiments and analyzed the data. Gustavo Bena\u0026iacute;m and Nieves Canudas assisted with the fluorescence analyses. Pablo Mart\u0026iacute;nez and Jos\u0026eacute; Bubis wrote the manuscript, and all authors commented on the preliminary version. All authors read and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e\u003cp\u003eThis research was supported by FONACIT, Caracas, Venezuela (grant numbers 20230PGP99 to JB and GB, and 2024PGP315 to GB), Decanato de Investigaci\u0026oacute;n y Desarrollo, Universidad Sim\u0026oacute;n Bol\u0026iacute;var, Caracas, Venezuela (to NU), and CDCH-UCV Group Research Project 2025 (to GB).\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eAll generated data is included either in the main content or in the supplementary material of the manuscript. If required, specific datasets are available from the corresponding authors on request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSung D, Lee L (2023) Natural-product-based fluorescent probes: recent advances and application. RSC Med Chem 14(3):412\u0026ndash;432. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1039/d2md00376g\u003c/span\u003e\u003cspan address=\"10.1039/d2md00376g\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJaswal S, Kumar J (2020) Review on fluorescent donor\u0026ndash;acceptor conjugated system as molecular probes. \u003cem\u003eMater. 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Chem \u0026ndash; Eur J 22(30):10627\u0026ndash;10637. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1002/chem.201600581\u003c/span\u003e\u003cspan address=\"10.1002/chem.201600581\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\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":"journal-of-fluorescence","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jofl","sideBox":"Learn more about [Journal of Fluorescence](https://www.springer.com/journal/10895)","snPcode":"10895","submissionUrl":"https://submission.nature.com/new-submission/10895/3","title":"Journal of Fluorescence","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Chalcone, DFT, Photophysical properties, Fluorescence","lastPublishedDoi":"10.21203/rs.3.rs-7430349/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7430349/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eChalcones constitute a distinct family of compounds with intrinsic fluorescence properties that make them valuable tools for a variety of applications. In this work, a new chalcone core derivative, (\u003cem\u003eE\u003c/em\u003e)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one, was synthesized via a Claisen\u0026ndash;Schmidt condensation reaction and fully characterized by IR, NMR spectroscopy and GC-MS analysis. Also was subsequently subjected to comprehensive photophysical and computational studies. For the photophysical characterization, the molar absorptivity coefficients and fluorescence quantum yields in methanol, acetonitrile, and chloroform were determined, along with an analysis of solvatochromic and solvatofluorochromic effects in different solvents and the assessment of the Stokes shift. The compound exhibited positive solvatochromism and solvatofluorochromism, providing valuable information on its polarity-dependent behavior. Computational analysis based on density functional theory elucidated the energy gaps between the boundary molecular orbitals and the electrostatic potential map, which corresponded to the structure of the compound and the trends observed in the photophysical study.\u003c/p\u003e","manuscriptTitle":"Synthesis, characterization, photophysical and DFT studies of (E)-1-(4-aminophenyl)-3-(1-benzyl-pyrrol-2-yl) prop-2-en-1-one, a novel aminochalcone","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-16 16:55:18","doi":"10.21203/rs.3.rs-7430349/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-09-23T11:58:10+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-20T19:42:29+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-18T15:33:07+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-18T13:53:23+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-17T20:31:43+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-15T04:38:41+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-13T18:48:11+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"221072825071784281872172671779125363878","date":"2025-09-10T12:30:06+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"187354157648695209929461723892166261992","date":"2025-09-09T13:46:42+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"113245795012489578923775079946327330761","date":"2025-09-09T07:01:52+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"319163782998167535437984366308992110456","date":"2025-09-09T03:54:19+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"317785545301008278569089041829339921892","date":"2025-09-08T14:35:52+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"269116778392240188078899480903442626286","date":"2025-09-08T14:19:10+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"329002504206217978958041230296052555153","date":"2025-09-08T14:04:59+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-08T11:39:32+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-26T12:53:57+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-26T12:53:50+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Fluorescence","date":"2025-08-22T03:29:32+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-fluorescence","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jofl","sideBox":"Learn more about [Journal of Fluorescence](https://www.springer.com/journal/10895)","snPcode":"10895","submissionUrl":"https://submission.nature.com/new-submission/10895/3","title":"Journal of Fluorescence","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"f7ba9472-42a4-478f-b16a-94741bb8bd0a","owner":[],"postedDate":"September 16th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-01T16:14:22+00:00","versionOfRecord":{"articleIdentity":"rs-7430349","link":"https://doi.org/10.1007/s10895-025-04645-9","journal":{"identity":"journal-of-fluorescence","isVorOnly":false,"title":"Journal of Fluorescence"},"publishedOn":"2025-11-28 15:58:45","publishedOnDateReadable":"November 28th, 2025"},"versionCreatedAt":"2025-09-16 16:55:18","video":"","vorDoi":"10.1007/s10895-025-04645-9","vorDoiUrl":"https://doi.org/10.1007/s10895-025-04645-9","workflowStages":[]},"version":"v1","identity":"rs-7430349","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7430349","identity":"rs-7430349","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}