[Cu 2 R 2 BrLi(thf) 3 ], R = Si(SiMe 3 ) 3 –a complex containing five-coordinate silicon in a three-centre two-electron bond (thf = tetrahydrofuran)

The title compound is obtained from the reaction of (Me3Si)3SiLi(thf)3 with CuBr in n-hexane and structurally characterised by X-ray diffraction; in [Cu2R2BrLi(thf)3], R = Si(SiMe3)3 one silyl ligand is bridging a very short Cu–Cu bond, resulting in a three-centre two-electron bond, while the second is terminally bound to copper; the other copper atom is linked to a lithium atom via a Cu ⋯ Br ⋯ Li bridge.