Amrit S. Nanuwa, Matthew D. Hoffman, Kiran Nandi and Johanna M. Blacquiere*,
{"title":"Selectivity of Ru and Fe PR2NR’2 Catalysts Toward Acceptorless Dehydrogenation of Benzylamine","authors":"Amrit S. Nanuwa, Matthew D. Hoffman, Kiran Nandi and Johanna M. Blacquiere*, ","doi":"10.1021/acs.organomet.4c0034510.1021/acs.organomet.4c00345","DOIUrl":null,"url":null,"abstract":"<p >The performance of six ruthenium catalysts and two iron catalysts were evaluated toward the acceptorless dehydrogenation of benzylamine. All catalysts shared the common structure [M(Cp/Cp*)(P<sup>R</sup><sub>2</sub>N<sup>R’</sup><sub>2</sub>)(MeCN)]PF<sub>6</sub> (M = Fe, Ru; Cp = cyclopentadienyl; Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl; P<sup>R</sup><sub>2</sub>N<sup>R’</sup><sub>2</sub> = 1,5-R′-3,7-R-1,5-diaza-3,7-diphosphacyclooctane) in which the P<sup>R</sup><sub>2</sub>N<sup>R’</sup><sub>2</sub> ligands contain a pendant tertiary amine that enables cooperative catalytic mechanisms. Catalytic activity and selectivity were evaluated to identify the optimal catalyst structural features. The iron catalyst [Fe(Cp)(P<sup>Ph</sup><sub>2</sub>N<sup>Ph</sup><sub>2</sub>)(MeCN)]PF<sub>6</sub> demonstrated near-exclusive selectivity for the acceptorless dehydrogenative coupled product, <i>N</i>-benzylidenebenzylamine. The absence of the hydrogen-borrowed (dibenzylamine) product indicates that this iron catalyst strongly favors dehydrogenation pathways over hydrogenation. This was confirmed through the control reactions. The performance of [Fe(Cp)(P<sup>Ph</sup><sub>2</sub>N<sup>Ph</sup><sub>2</sub>)(MeCN)]PF<sub>6</sub> was optimized, but the catalyst was ineffective toward a broader scope of substrates.</p>","PeriodicalId":56,"journal":{"name":"Organometallics","volume":null,"pages":null},"PeriodicalIF":2.5000,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Organometallics","FirstCategoryId":"92","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acs.organomet.4c00345","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0
Abstract
The performance of six ruthenium catalysts and two iron catalysts were evaluated toward the acceptorless dehydrogenation of benzylamine. All catalysts shared the common structure [M(Cp/Cp*)(PR2NR’2)(MeCN)]PF6 (M = Fe, Ru; Cp = cyclopentadienyl; Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl; PR2NR’2 = 1,5-R′-3,7-R-1,5-diaza-3,7-diphosphacyclooctane) in which the PR2NR’2 ligands contain a pendant tertiary amine that enables cooperative catalytic mechanisms. Catalytic activity and selectivity were evaluated to identify the optimal catalyst structural features. The iron catalyst [Fe(Cp)(PPh2NPh2)(MeCN)]PF6 demonstrated near-exclusive selectivity for the acceptorless dehydrogenative coupled product, N-benzylidenebenzylamine. The absence of the hydrogen-borrowed (dibenzylamine) product indicates that this iron catalyst strongly favors dehydrogenation pathways over hydrogenation. This was confirmed through the control reactions. The performance of [Fe(Cp)(PPh2NPh2)(MeCN)]PF6 was optimized, but the catalyst was ineffective toward a broader scope of substrates.
期刊介绍:
Organometallics is the flagship journal of organometallic chemistry and records progress in one of the most active fields of science, bridging organic and inorganic chemistry. The journal publishes Articles, Communications, Reviews, and Tutorials (instructional overviews) that depict research on the synthesis, structure, bonding, chemical reactivity, and reaction mechanisms for a variety of applications, including catalyst design and catalytic processes; main-group, transition-metal, and lanthanide and actinide metal chemistry; synthetic aspects of polymer science and materials science; and bioorganometallic chemistry.