Isolation of two bis(silyl)nickel complexes with Si–Si bond formation in a single-crystal-to-single-crystal fashion

Abstract

A unique penta-coordinate nickel complex [{1,2-C₆H₄(SiMe₂)(SiH)}₂Ni(PEt₃)(depe)] (6) that generates two new Si–Si single bonds has been prepared exclusively by the reaction of a chelating silyl hydride 1-(dimethylsilyl)-2-silylbenzene (4) and Ni(depe)(PEt₃)₂ (depe = Et₂PCH₂CH₂PEt₂) in a 2 : 1 ratio. Complex 6 is the first example of mononuclear silyl nickel complexes containing a Si–Si single bond formed in situ. Interestingly, framework 6 exhibits reversible single-crystal-to-single-crystal transformations upon the removal and rebinding of the coordinating PEt₃ molecule, which give rise to a PEt₃-free complex [{1,2-C₆H₄(SiMe₂)(SiH)}₂Ni(depe)] (6′), concomitant with the alteration of the coordination geometry of central metal atoms.