Formic acid dehydrogenation using Ruthenium-POP pincer complexes in ionic liquids

Formic acid dehydrogenation using Ruthenium-POP pincer complexes in ionic liquids | 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 Article Formic acid dehydrogenation using Ruthenium-POP pincer complexes in ionic liquids Alexander Tobias Nikol, Brenda Rabell, René Wugt Larsen, Martin Nielsen This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4654797/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 31 Oct, 2024 Read the published version in Scientific Reports → Version 1 posted 16 You are reading this latest preprint version Abstract Formic acid is one of the most promising candidates for the long-term storage of hydrogen in liquid form. Herein, we present a new collection of ruthenium pincer complexes of the general formula [RuHCl(POP)(PPh 3 )] using commercially available or easy-to-synthesize tridentate xantphos-type POP pincer ligands. We applied these complexes in the dehydrogenation of formic acid to CO 2 and H 2 using the ionic liquid BMIM OAc as solvent under reflux-free, mild conditions. The best performing catalyst with respect to maximum turnover frequency, the literature-known complex [RuHCl(xantphos)(PPh 3 )], produced a turnover frequency of 4525 h − 1 with 74% conversion after 10 minutes at 90°C and complete conversion (> 98%) occurring within 3 hours. On the other hand, the best overall performing catalyst, the novel complex [RuHCl( i Pr-dbfphos)(PPh 3 )], facilitated full conversion within 1 hour leading to an overall turnover frequency of 1009 h − 1 . Moreover, catalytic activity was observed at temperatures as low as 60°C. Finally, Arrhenius plots suggest activation energies between 50.4 and 63.7 kJ mol − 1 . Only CO 2 and H 2 are observed in the gas phase, with no CO detected. Physical sciences/Chemistry/Catalysis/Catalyst synthesis Physical sciences/Chemistry/Catalysis/Catalytic mechanisms Physical sciences/Chemistry/Catalysis/Homogeneous catalysis Physical sciences/Chemistry/Green chemistry/Ionic liquids Physical sciences/Chemistry/Green chemistry/Renewable energy Physical sciences/Chemistry/Green chemistry/Sustainability Physical sciences/Chemistry/Inorganic chemistry/Organometallic chemistry Ruthenium phosphine phosphane POP-pincer pincer complex Xantphos DBFphos tridentate ligand ionic liquids formic acid dehydrogenation LOHC. Full Text Additional Declarations No competing interests reported. Supplementary Files SciRepRuPOPFASI.docx Cite Share Download PDF Status: Published Journal Publication published 31 Oct, 2024 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 29 Aug, 2024 Reviews received at journal 23 Aug, 2024 Reviews received at journal 22 Aug, 2024 Reviews received at journal 20 Aug, 2024 Reviews received at journal 18 Aug, 2024 Reviews received at journal 18 Aug, 2024 Reviewers agreed at journal 12 Aug, 2024 Reviewers agreed at journal 11 Aug, 2024 Reviewers agreed at journal 09 Aug, 2024 Reviewers agreed at journal 09 Aug, 2024 Reviewers agreed at journal 09 Aug, 2024 Reviewers invited by journal 08 Aug, 2024 Editor assigned by journal 08 Aug, 2024 Editor invited by journal 05 Aug, 2024 Submission checks completed at journal 31 Jul, 2024 First submitted to journal 28 Jun, 2024 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-4654797","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":344142853,"identity":"080210f7-2dd2-4f87-bd28-da815777531e","order_by":0,"name":"Alexander Tobias Nikol","email":"","orcid":"","institution":"Technical University of Denmark (DTU)","correspondingAuthor":false,"prefix":"","firstName":"Alexander","middleName":"Tobias","lastName":"Nikol","suffix":""},{"id":344142854,"identity":"d3eb6341-8b1a-44be-a2ff-379626580a91","order_by":1,"name":"Brenda Rabell","email":"","orcid":"","institution":"Technical University of Denmark (DTU)","correspondingAuthor":false,"prefix":"","firstName":"Brenda","middleName":"","lastName":"Rabell","suffix":""},{"id":344142855,"identity":"0f048a5d-f50d-43ce-a35d-1d0b9dffe635","order_by":2,"name":"René Wugt Larsen","email":"","orcid":"","institution":"Technical University of Denmark (DTU)","correspondingAuthor":false,"prefix":"","firstName":"René","middleName":"Wugt","lastName":"Larsen","suffix":""},{"id":344142857,"identity":"77db98dd-2a62-48ac-8485-580abf93b079","order_by":3,"name":"Martin Nielsen","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAx0lEQVRIiWNgGAWjYLCCBAYbAwYGxgYGHhDvDHFa0qBaEojVwsBw2ABMEaVFt/3sswcPKs4b84sdbmB4++MwA9+ZA/i1mJ1JNzdIOHPbTHJ2YgPjnITDDJJnGwhoOZDGJpHYdtvG4HZiAzMPUIvBeQIOMzv/DKjl3zkbe+K13ADZ0nDAzEAapoWgw24AbUk4lmwsAbTl4Jy0dB5Jgt4/n8Ym+aPGzrB/dvrDB29srOX4ziQQcBkyABnPQ4L6UTAKRsEoGAW4AAAjo0ZNbh/hmwAAAABJRU5ErkJggg==","orcid":"","institution":"Technical University of Denmark (DTU)","correspondingAuthor":true,"prefix":"","firstName":"Martin","middleName":"","lastName":"Nielsen","suffix":""}],"badges":[],"createdAt":"2024-06-28 12:32:40","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4654797/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4654797/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-024-76782-3","type":"published","date":"2024-10-31T16:20:04+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":68207141,"identity":"8b01abf9-6572-4f5b-9647-ed28a6747791","added_by":"auto","created_at":"2024-11-04 16:35:14","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":663790,"visible":true,"origin":"","legend":"","description":"","filename":"SciRepRuPOPFAManuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4654797/v1_covered_a5ba1ef6-f0ec-46ca-8886-c21daf7e5bce.pdf"},{"id":63367399,"identity":"d1737060-e9b5-4e15-9fe0-4dc48c2ad2ac","added_by":"auto","created_at":"2024-08-27 11:30:46","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":16841449,"visible":true,"origin":"","legend":"","description":"","filename":"SciRepRuPOPFASI.docx","url":"https://assets-eu.researchsquare.com/files/rs-4654797/v1/8600fa9b286444e9405210f3.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Formic acid dehydrogenation using Ruthenium-POP pincer complexes in ionic liquids","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Ruthenium, phosphine, phosphane, POP-pincer, pincer complex, Xantphos, DBFphos, tridentate ligand, ionic liquids, formic acid, dehydrogenation, LOHC.","lastPublishedDoi":"10.21203/rs.3.rs-4654797/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4654797/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eFormic acid is one of the most promising candidates for the long-term storage of hydrogen in liquid form. Herein, we present a new collection of ruthenium pincer complexes of the general formula [RuHCl(POP)(PPh\u003csub\u003e3\u003c/sub\u003e)] using commercially available or easy-to-synthesize tridentate xantphos-type POP pincer ligands. We applied these complexes in the dehydrogenation of formic acid to CO\u003csub\u003e2\u003c/sub\u003e and H\u003csub\u003e2\u003c/sub\u003e using the ionic liquid BMIM OAc as solvent under reflux-free, mild conditions. The best performing catalyst with respect to maximum turnover frequency, the literature-known complex [RuHCl(xantphos)(PPh\u003csub\u003e3\u003c/sub\u003e)], produced a turnover frequency of 4525 h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e with 74% conversion after 10 minutes at 90\u0026deg;C and complete conversion (\u0026gt;\u0026thinsp;98%) occurring within 3 hours. On the other hand, the best overall performing catalyst, the novel complex [RuHCl(\u003cem\u003ei\u003c/em\u003ePr-dbfphos)(PPh\u003csub\u003e3\u003c/sub\u003e)], facilitated full conversion within 1 hour leading to an overall turnover frequency of 1009 h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Moreover, catalytic activity was observed at temperatures as low as 60\u0026deg;C. Finally, Arrhenius plots suggest activation energies between 50.4 and 63.7 kJ mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Only CO\u003csub\u003e2\u003c/sub\u003e and H\u003csub\u003e2\u003c/sub\u003e are observed in the gas phase, with no CO detected.\u003c/p\u003e","manuscriptTitle":"Formic acid dehydrogenation using Ruthenium-POP pincer complexes in ionic liquids","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-27 11:30:40","doi":"10.21203/rs.3.rs-4654797/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-08-29T10:02:04+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-08-23T11:02:26+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-08-23T01:20:20+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-08-20T12:06:59+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-08-19T01:00:28+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-08-18T09:13:21+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"40208856163354707349207533910993716477","date":"2024-08-12T07:00:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"47486634011713425063181517767846903788","date":"2024-08-11T08:21:17+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"315195547362818108792184407544654652709","date":"2024-08-10T01:06:29+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"171554272904536920324049776952921990892","date":"2024-08-09T09:35:45+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"106838313208164906295605978067938136379","date":"2024-08-09T05:56:11+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-08-09T01:59:15+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-08-09T01:45:14+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-08-05T18:16:01+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-07-31T04:50:40+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2024-06-28T12:31:27+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"d66467fa-7185-4c1f-99df-d3b83e84f88f","owner":[],"postedDate":"August 27th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":36474504,"name":"Physical sciences/Chemistry/Catalysis/Catalyst synthesis"},{"id":36474505,"name":"Physical sciences/Chemistry/Catalysis/Catalytic mechanisms"},{"id":36474506,"name":"Physical sciences/Chemistry/Catalysis/Homogeneous catalysis"},{"id":36474507,"name":"Physical sciences/Chemistry/Green chemistry/Ionic liquids"},{"id":36474508,"name":"Physical sciences/Chemistry/Green chemistry/Renewable energy"},{"id":36474509,"name":"Physical sciences/Chemistry/Green chemistry/Sustainability"},{"id":36474510,"name":"Physical sciences/Chemistry/Inorganic chemistry/Organometallic chemistry"}],"tags":[],"updatedAt":"2024-11-04T16:25:13+00:00","versionOfRecord":{"articleIdentity":"rs-4654797","link":"https://doi.org/10.1038/s41598-024-76782-3","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2024-10-31 16:20:04","publishedOnDateReadable":"October 31st, 2024"},"versionCreatedAt":"2024-08-27 11:30:40","video":"","vorDoi":"10.1038/s41598-024-76782-3","vorDoiUrl":"https://doi.org/10.1038/s41598-024-76782-3","workflowStages":[]},"version":"v1","identity":"rs-4654797","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4654797","identity":"rs-4654797","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}