Access to ligand-stabilized PH-containing phosphenium complexes.

While the chemistry of phosphenium compounds, including metal complexes thereof, is very well established, few derivatives having a P-H bond have been described, yet. This work describes rational access to donor-stabilised phosphenium metal complexes possessing a P-H bond using protonation reactions of stable phosphinidene complex adducts. While most Brønsted-Lowry acids yield formal 1,1-addition products at the phosphorus centre under the loss of the donor, super-strong acids having weakly coordinating anions enable access to donor-stabilised P-H phosphenium complex salts. The latter possess N-methylimidazole as a donor (to phosphorus) and the N-P interaction has been studied theoretically.