Synthesis, Structure, and Deprotonation of a Mesitylphosphido-Bridged Cyclopentadienylnickel(II) Dimer

The bridging phosphido complex [NiCp(μ-PHMes)]2 (1, Mes = 2,4,6-Me3C6H2) was prepared from NiCp2 and PH2Mes. Deprotonation and methylation of 1 yields (NiCp)2(μ-PHMes)(μ-PMeMes) (4) and [NiCp(μ-PMeMes)]2 (6) via observable anionic phosphinidene intermediates. NMR spectroscopy was used to characterize syn and anti isomers of 1, 4, and 6, and the structures of anti-1a and syn-6b were determined by X-ray crystallography.