Ti–Ru bimetallic complexes: catalysts for ring-closing metathesis

The reaction of the titanocene monophosphanes (1–4) with the dimer [(p-cymene)RuCl2]2 gives the heterobimetallic compounds (p-cymene)[(η5-C5H5)(μ-η5:η1-C5H4(CR2)nPR′2)TiCl2]RuCl2 (5–8). The structure of 8, determined by X-ray diffraction, is reported here. A preliminary assessment of the performance of these complexes in ring-closing metathesis (RCM) revealed an excellent Ti–Ru–allenylidene pre-catalyst 12.