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

The bridging phosphido complex [NiCp(μ-PHMes)]<sub>2</sub> (<b>1</b>, Mes = 2,4,6-Me<sub>3</sub>C<sub>6</sub>H<sub>2</sub>) was prepared from NiCp<sub>2</sub> and PH<sub>2</sub>Mes. Deprotonation and methylation of <b>1</b> yields (NiCp)<sub>2</sub>(μ-PHMes)(μ-PMeMes) (<b>4</b>) and [NiCp(μ-PMeMes)]<sub>2</sub> (<b>6</b>) via observable anionic phosphinidene intermediates. NMR spectroscopy was used to characterize syn and anti isomers of <b>1</b>, <b>4</b>, and <b>6</b>, and the structures of anti-<b>1a</b> and syn-<b>6b</b> were determined by X-ray crystallography.