{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"submitter":["Adillon EH"],"funding":["Resnick Sustainability Institute for Science, Energy and Sustainability, California Institute of Technology","Basic Energy Sciences","National Defense Science and Engineering Graduate"],"pagination":["30204-30211"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC11544690"],"repository":["biostudies-literature"],"omics_type":["Unknown"],"volume":["146(44)"],"pubmed_abstract":["Reagents capable of concerted proton-electron transfer (CPET) reactions can access reaction pathways with lower reaction barriers compared to stepwise pathways involving electron transfer (ET) and proton transfer (PT). To realize reductive multielectron/proton transformations involving CPET, one approach that has shown recent promise involves coupling a cobaltocene ET site with a protonated arylamine Brønsted acid PT site. This strategy colocalizes the electron/proton in a matter compatible with a CPET step and net reductive electrocatalysis. To probe the generality of such an approach a class of C,C'-diaryl-<i>o</i>-carboranes is herein explored as a conceptual substitute for the cobaltocene subunit, with an arylamine linkage still serving as a colocalized Brønsted base suitable for protonation. The featured <i>o</i>-carborane (Ph<b>Cb</b>Ph<sup>N</sup>) can be reduced and protonated to generate an N-H bond with a weak effective bond dissociation free energy (BDFE<sub>eff</sub>) of 31 kcal/mol, estimated with measured thermodynamic data. This N-H bond is among the lowest measured element-H bonds for analyzed nonmetal compounds. Distinct solid-state crystal structures of the one- and two-electron reduced forms of diaryl-<i>o</i>-carboranes are disclosed to gain insight into their well-behaved redox characteristics. The singly reduced, protonated form of the diaryl-<i>o</i>-carborane can mediate multi-ET/PT reductions of azoarenes, diphenylfumarate, and nitrotoluene. In contrast to the aforementioned cobaltocene system, available mechanistic data disclosed herein support these reactions occurring by a rate-limiting ET step and not a CPET step. A relevant hydrogen evolution reaction (HER) reaction was also studied, with data pointing to a PT/ET/PT mechanism, where the reduced carborane core is itself highly stable to protonation."],"journal":["Journal of the American Chemical Society"],"pubmed_title":["A Carborane-Derived Proton-Coupled Electron Transfer Reagent."],"pmcid":["PMC11544690"],"funding_grant_id":["DE-SC0019136"],"pubmed_authors":["Peters JC","Adillon EH"],"additional_accession":[]},"is_claimable":false,"name":"A Carborane-Derived Proton-Coupled Electron Transfer Reagent.","description":"Reagents capable of concerted proton-electron transfer (CPET) reactions can access reaction pathways with lower reaction barriers compared to stepwise pathways involving electron transfer (ET) and proton transfer (PT). To realize reductive multielectron/proton transformations involving CPET, one approach that has shown recent promise involves coupling a cobaltocene ET site with a protonated arylamine Brønsted acid PT site. This strategy colocalizes the electron/proton in a matter compatible with a CPET step and net reductive electrocatalysis. To probe the generality of such an approach a class of C,C'-diaryl-<i>o</i>-carboranes is herein explored as a conceptual substitute for the cobaltocene subunit, with an arylamine linkage still serving as a colocalized Brønsted base suitable for protonation. The featured <i>o</i>-carborane (Ph<b>Cb</b>Ph<sup>N</sup>) can be reduced and protonated to generate an N-H bond with a weak effective bond dissociation free energy (BDFE<sub>eff</sub>) of 31 kcal/mol, estimated with measured thermodynamic data. This N-H bond is among the lowest measured element-H bonds for analyzed nonmetal compounds. Distinct solid-state crystal structures of the one- and two-electron reduced forms of diaryl-<i>o</i>-carboranes are disclosed to gain insight into their well-behaved redox characteristics. The singly reduced, protonated form of the diaryl-<i>o</i>-carborane can mediate multi-ET/PT reductions of azoarenes, diphenylfumarate, and nitrotoluene. In contrast to the aforementioned cobaltocene system, available mechanistic data disclosed herein support these reactions occurring by a rate-limiting ET step and not a CPET step. A relevant hydrogen evolution reaction (HER) reaction was also studied, with data pointing to a PT/ET/PT mechanism, where the reduced carborane core is itself highly stable to protonation.","dates":{"release":"2024-01-01T00:00:00Z","publication":"2024 Nov","modification":"2025-04-05T23:11:20.389Z","creation":"2025-04-05T23:11:20.389Z"},"accession":"S-EPMC11544690","cross_references":{"pubmed":["39466817"],"doi":["10.1021/jacs.4c09007"]}}