Novel halogen-bridged bisphosphine nickel(II) complexes

Reaction of [NiCl2(dtbpe)] (dtbpe = 1,2-bis(di-tert-butylphosphino)ethane) with one equivalent of NaBArF4 (BArF4 = tetrakis[3,5-bis(trifluoromethyl)phenyl]borate) gives the dinuclear chloro-bridged nickel complex [Ni2(μ-Cl)2(dtbpe)2](BArF4)2 (1). [Ni(solv)6](BF4)2 reacts with dtbpe to give, depending on the solvent, the fluoro-bridged complex [Ni2(μ-F)2(dtbpe)2](BF4)2 (2) (solv = THF) or the mononuclear chelate complex [Ni(MeCN)2(dtbpe)](BF4)2 (3) (solv = MeCN). In 1–3, nickel cations are coordinated in a square-planar fashion according to X-ray crystallography. No Ni–Ni interaction was observed in dinuclear halogen-bridged complexes 1 and 2.