%AAbhyankar, Preshit [Department of Chemistry University at Buffalo State University of New York Buffalo New York 14260 USA]%AMacMillan, Samantha [Department of Chemistry and Chemical Biology Cornell University Ithaca New York 14853 USA]%ALacy, David [Department of Chemistry University at Buffalo State University of New York Buffalo New York 14260 USA]%BJournal Name: Chemistry – A European Journal; Journal Volume: 28; Journal Issue: 53; Related Information: CHORUS Timestamp: 2023-08-21 19:19:21 %D2022%IWiley Blackwell (John Wiley & Sons) %JJournal Name: Chemistry – A European Journal; Journal Volume: 28; Journal Issue: 53; Related Information: CHORUS Timestamp: 2023-08-21 19:19:21 %K %MOSTI ID: 10372502 %PMedium: X %TBench‐Stable Dinuclear Mn(I) Catalysts in E ‐Selective Alkyne Semihydrogenation: A Mechanistic Investigation** %XAbstract

Dinuclear manganese hydride complexes of the form [Mn2(CO)8(μ‐H)(μ‐PR2)] (R=Ph,1; R=iPr,2) were used inE‐selective alkyne semi‐hydrogenation (E‐SASH) catalysis. Catalyst speciation studies revealed rich coordination chemistry and the complexes thus formed were isolated and in turn tested as catalysts; the results underscore the importance of dinuclearity in engendering the observedE‐selectivity and provide insights into the nature of the active catalyst. The insertion product obtained from treating2with (cyclopropylethynyl)benzene contains acis‐alkenyl bridging ligand with the cyclopropyl ring being intact. Treatment of this complex with H2affords exclusivelytrans‐(2‐cyclopropylvinyl)benzene. These results, in addition to other control experiments, indicate a non‐radical mechanism forE‐SASH, which is highly unusual for Mn−H catalysts. The catalytically active species are virtually inactive towardscistotransalkene isomerization indicating that theE‐selective process is intrinsic and dinuclear complexes play a critical role. A reaction mechanism is proposed accounting for the observed reactivity which is fully consistent with a kinetic analysis of the rate limiting step and is further supported by DFT computations.

%0Journal Article