Synthesis and characterisation of new PCsp3P-supported nickel complexes

The coordination behaviour of the aliphatic pincer ligand cis-1,3-bis-((di-tert-butylphosphino)methyl)cyclohexane with NiCl2 and NiBr2 was studied. Reflux in toluene afforded cyclometalated, tridentate PCsp3P pincer complexes, that were characterised by elemental analysis and NMR spectroscopy; the solid state structures were determined by X-ray diffraction showing an unusually long Ni–Br bond in the bromo complex. A preliminary account of their reactivity is reported and they were found to be unreactive towards base and hydride sources and to be poor catalysts in Kumada coupling reactions.