Combined B-H and Si-H Bond Activations at Ruthenium

The coordination of 2-mercaptobenzothiazolyl (mbz) and 2-mercaptopyridyl (mp) to a [Ru]-H precursor led to the isolation of two hydri do ( dihydrob orate ) complexes [ RuH ( P Cy3)2{x-3-H,H,S-(H)2BH(L)}] (L = mbz (1a), mp (1b)). Oxidative addition of secondary and tertiary silanes to 1a and 1b afforded the dihydrido ruthenium(IV) [RuH2(SiPh2R)(PCy3){x-3-H,H,S-(H)2BH(L)}] (R = H, L = mbz (2a), mp (2b); R = Me, L = mbz (2c)) featuring a coordinated borohydride moiety and a silyl ligand in weak interaction with the two hydride ligands of the ruthenium center. 1D and 2D NMR investigations at different temperatures as well as D2 reactivity, enabled to characterize exchange between every Si-H, Ru-H, and B-H hydride sites.