Single component ruthenium(IV) catalysts for the ring-opening polymerization of norbornene

Article abstract of DOI:10.1016/0022-328X(94)05244-6

The neutral complexes 3:η³-C10H16)Cl2> 2a and 3:η³-C10H16)Cl2> 2b were obtained by addition of neutral ligands to <3:η³-C10H16)(μ-Cl)Cl>2> 1 and their structure was determined by both NMR spectroscopy and crystal structure analysis in case of 2a (triclinic, space group P1, a = 10.556(6) Angstroem, b = 10.823(5) Angstroem, c = 13.156(7) Angstroem, α = 93.34 deg, β = 108.47(3) deg, γ = 112.64(3) deg, V = 1288(1) Angstroem³, Z = 2, D_calc. = 1.71 g cm^-3, R_w = 0.021).The compounds 2a and 2b are very active single component catalysts for ring-opening polymerization of norbornene.Their catalytic activity depends on the displacement of the ligand L by the olefin.The polymers thus produced have high molecular weights M_n of 4.5*10⁵ g mol^-1 with a monomodal distribution and with polydispersities from 2.4 to 5.3.The cis selectivity of 2a and 2b (up to 30percent) is higher than that of many other ruthenium-based catalysts for the polymerization of strained cyclo-olefins.Keywords: Allylruthenium(IV); Norbornene; Polymerization; Ring opening