Synthesis and evaluation of new RuCl2(p-cymene)(ER2R′) and (η1:η6-phosphinoarene)RuCl2 complexes as ring-opening metathesis polymerization catalysts

New RuCl2(p-cymene)(ER2R′) complexes (E=P, As, Sb; R, R′=H, alkyl, arylalkyl) have been synthesized and used as catalyst precursors for the ring-opening metathesis polymerization (ROMP) of cyclooctene, cyclopentene, and norbornene. When ER2R′ was a phosphinoarene, the p-cymene ligand could be displaced upon heating and tethered (η1:η6-phosphinoarene)RuCl2 complexes were obtained. Simple thermogravimetric analysis (TGA) of the complexes provided clear-cut indication on their potential catalytic activity in ROMP.