Cyclopentadienylnickel Chelates with Secondary or Tertiary Phosphane Tethers Bearing Imidazol-2-ylidene Ligands

Abstract

Treatment of cyclopentadienylnickel chloro or bromo chelates bearing either a tertiary 2-(di-tert-butyl)phosphanylethyl or a secondary 2-(2,4,6-trimethylphenyl)phosphanylethyl tether with imidazolylidene (Arduengo carbene) ligands results in cationic or electroneutral carbene complexes with either a decoordinated or a chelated tether. The outcome depends on the nature of the carbene, the counter anion, and the reactant stoichiometry. The results are the basis of ongoing investigations directed towards a deprotonation of the chelated cationic complexes with a secondary phosphorus atom.