OsHCl(CO)(PiPr3)2 as catalyst for ring-opening metathesis polymerization (ROMP) and tandem ROMP–hydrogenation of norbornene and 2,5-norbornadiene

Complex OsHCl(CO)(PiPr3)2 catalyzes the ring-opening metathesis polymerization (ROMP) of norbornene and 2,5-norbornadiene to give poly(norbornene) and poly(norbornadiene), respectively. In both cases the resulting polymers have a high cis (74–95%) content. The stereoregularity or tacticity of the cyclopentane and cyclopentene ring sequences in poly(norbornene) and poly(norbornadiene) estimated from the 13C{1H} NMR spectra of the hydrogenated derivatives was found to be syndiotactic. Complex OsHCl(CO)(PiPr3)2 is also active in tandem ROMP–hydrogenation of norbornene and 2,5-norbornadiene. At 40 °C and 3 atm of H2, poly(norbornene) is fully hydrogenated in 48 h, while poly(norbornadiene) is fully hydrogenated in 48 h at 75 °C and 3 atm of H2. The complex RuHCl(CO)(PiPr3)2 is also active in ROMP and tandem ROMP–hydrogenation of norbornene, obtaining trans-poly(norbornene) and hydrogenated poly(norbornene), respectively.