Structure and catalytic activity of rhodium(I) carbene complexes in polymerization of phenylacetylene

Rh(I) carbene complexes of [RhX(bmim)(η4-1,5-cod)] type (bmim = 1-butyl-3-methyl imidazolium cation, X = Cl 2, Br 3, I 4), obtained in the reaction of [Rh(OMe)(η4-1,5-cod)]2 (1) with [bmim]X ionic liquids, catalyzed polymerization of phenylacetylene (PA) to cis-polyphenylacetylene (PPA) in CH2Cl2 and in ionic liquids. The yield of PPA increased and molecular weight (Mw) decreased after addition of phosphorus ligands PPh3 or P(OPh)3. Complex 4 reacted with P(OPh)3 giving cis-[RhI(bmim)(P(OPh)3)2] (5) complex which catalyzed oligomerization but not polymerization of PA.