Heterometallic <scp>Mg‐Ni‐Mg</scp> Complex Promoted Hydrosilylation of Alkenes: Catalytic Performance and Intermediates Characterization<sup>†</sup>
Yanping Cai, Shengjie Jiang, Xin Xu
Abstract
Comprehensive Summary Heteronuclear metal complexes have played an increasingly important role in both small molecules activation and catalytic transformation due to the potential metal‐metal synergies. In this work, we reported that the well‐defined Mg‐Ni‐Mg complex [( L Mg) 2 Ni(C 2 H 4 ) 2 ] { L = [(DippNCMe) 2 CH] − , Dipp = 2,6‐ i Pr 2 C 6 H 3 } was capable of catalyzing the conversion of a diverse array of terminal alkenes to hydrosilylated products in anti ‐Markovnikov fashion using PhSiH 3 as the silicon source. The stoichiometric reaction of heterometallic Mg‐Ni‐Mg complex with one equivalent PhSiH 3 obtained a silyl‐nickel‐monohydride complex [( L Mg) 2 NiH(C 2 H 4 )(SiHPhEt)] featuring a Ni‐Si‐H‐Mg interaction. Moreover, treatment of heterometallic Mg‐Ni‐Mg complex with three equivalents PhSiH 3 provided the silyl‐nickel‐trihydride complex [( L Mg) 2 NiH 3 (SiHPhEt)] with three hydride‐bridged at Mg‐Ni‐Mg fragment. Further reactions of the resultant silyl‐nickel complexes with alkenes, e.g., ethylene and styrene, yielded the corresponding alkene‐coordinated Mg‐Ni‐Mg complexes [( L Mg) 2 Ni(C 2 H 4 ) 2 ], [( L Mg) 2 NiH 2 (C 2 H 4 )] and [( L Mg) 2 NiH 2 (CH 2 CHPh)], respectively, with the elimination of PhEtSiH 2 . Based on the control experiments, both silyl‐nickel‐monohydride and silyl‐nickel‐trihydride complexes were considered as active intermediates in the catalytic hydrosilylation reaction.