Highly 2,3-selective polymerization of phenylallene and its derivatives by vanadium complexes

Vanadium complexes containing bulky ligands were investigated for allene polymerization. Such complexes exhibit distinguished 2,3-selectivity (>99%) for phenylallene (PA) polymerization, which was proved from the corresponding nuclear magnetic resonance spectra. In particular, the catalysts with different structures show extremely high 2,3-selectivity. High molecular weight polymers (up to 740 kDa) were obtained in the presence of AlⁱBu₃ as a co-catalyst. Also, the polymerization of monomer containing a methoxy or bromine group smoothly proceeded using the vanadium complexes.