Air-Stable 14-Electron Rhodium(III) Complexes Bearing Si,N Ligands as Catalysts in Hydrolysis of Silanes

Abstract

Unsaturated 14-electron Rh(III) complexes are of great interest because of their involvement in stoichiometric and catalytic processes. Herein, we report the synthesis and characterization of one neutral and three cationic Rh(III) complexes bearing Si,N ligands, two of which are putative 14-electron cationic complexes. The reaction of the rhodium(I) precursor [RhCl(coe)2]2 with 8-(dimethylsilyl)quinoline (L1) resulted in the formation of the neutral rhodium(III) complex {Rh(Cl)(κ2-L1)2} (1-L1). From this compound, the cationic complex {Rh(κ2-L1)2(NCMe)}[BAr4F] (2-L1) can be synthesized by abstraction of the chlorine with Na[BAr4F]. The neutral complexes based on 8-(dimethylsilyl)-2-methylquinoline (L2) and 4-(dimethylsilyl)-9-phenylacridine (L3) could not be synthesized due to the bulky nature of the ligands. Therefore, the cationic compounds {Rh(κ2-L2)2}[BAr4F] (2-L2) and {Rh(κ2-L3)2}[BAr4F] (2-L3) were synthesized directly and proved to be very stable (solid and solution). Experimental (NMR and X-ray) and theoretical (NBO, QTAIM, and NCI) studies were performed and determined that the stability of the complexes is provided by weak agostic interactions. Furthermore, the cationic complexes were found to be active as catalysts in the hydrolysis of dihydrosilanes.