nido-Pentaboranyl complexes of cadmium

Abstract

The complexes [Cd(µ-B₅H₈)Cl(PPh₃)] and [Cd(µ-1-BrB₅H₇)Cl(PPh₃)] have been prepared by reaction of [CdCl₂(PPh₃)₂] with the potassium salts of the appropriate pentaborane anions. On the basis of boron-decoupled ¹H, proton-decoupled, ¹¹B and ³¹P n.m.r. spectra the complexes have been shown to be non-fluxional, η² complexes of the ligands [B₅H₈]^– and [1-BrB₅H₇]^–. The cadmium is formally a 16-electron species and the structure resembles that recently established by X-ray analysis for the ‘isoelectronic’ copper complex [Cu(µ-B₅H₈)(PPh₃)₂]. Attempts to prepare analogous complexes of zinc and mercury have been unsuccessful.