Operationally unsaturated ruthenium complex stabilized by a phosphine 1-azaallyl ligand.

Coordinatively unsaturated transition-metal compounds stabilized by supplemental electron donation from π-basic ligands are described as "operationally unsaturated". Such complexes are useful analogues of active catalyst structures that readily react with substrate molecules. We report that [PhP(CH)NCHC(CH)] (L1) effectively stabilizes Ru(II) in an operationally unsaturated form.