Abstract: A polymerization system for ring opening polymerization of cycloolefins, comprising a catalyst [MOX2L2], a Lewis acid as co-catalyst, and a chain-transfer agent, 1

Abstract: A polymerization system for ring opening polymerization of cycloolefins, comprising a catalyst [MoOX2L2], a Lewis acid as co-catalyst, and a chain-transfer agent, wherein (1) both X groups are the same halogen atom selected from the group consisting of Cl and Br, and both L groups are the same halogen atom as X; or (2) both of the X groups are the same halogen atom selected from the group consisting of Cl and Br, and both of the L groups are the same straight chain or branched alkyl group having 1-4 carbon atoms; or (3) both X groups are the same halogen atom selected from the group consisting of Cl and Br, and both L groups are the same straight chain or branched alkoxy group having 1-4 carbon atoms; or (4) both X groups are the same alkyl group having 1-4 carbon atoms, and both L groups are the same alkoxy group having 1-4 carbon atoms; or (5) one X group is a halogen atom selected from the group consisting of Cl and Br, and the other X group together with both L groups cons

Abstract: Penta-coordinated ruthenium catalysts for the metathesis reactions of olefins, in particular ring opening metathesis polymerization (ROMP) of cyclo-olefin monomers, which are cationic complexes represented by formula I, II or III: wherein each of X1 and X2, which may be the same or different, is an optionally substituted C3-C20 hydrocarbon group having an allyl moiety as an end group bonded to the ruthenium atom, or X1 and X2 together form a group, optionally substituted, which results from dimerization of an alkene and has at each end an allyl group bonded to the ruthenium atom; L1 and L2 are mono-dentate neutral electron donor ligands, preferably highly sterically encumbered neutral electron donor ligands such as alkyl phosphines or amines; L{circumflex over ( )}L is a bidentate neutral electron donor ligand, preferably phosphine, amino, imino, arsine or arphos; L3 is a solvent molecule or a neutral mono-dentate electron donor ligand; L{circumflex over ( )}L{circumflex over ( )}L is a trid

Abstract: Penta-coordinated ruthenium or osmium catalysts for metathesis reactions of olefins, which are cationic complexes represented by formulas I, II or III: wherein M is ruthenium or osmium; each of X1 and X2, which may be the same or different, is an optionally substituted C3-C20 hydrocarbon group having an allyl moiety as an end group bonded to the central metal atom M, or X1 and X2 together form a group, optionally substituted, which results from dimerization of an alkene and has at each end an allyl moiety bonded to the central metal atom M, L1 is a neutral electron donor ligand; L2 is a carbene group; L3 is a neutral electron donor ligand which may be the same as or different from L1, or L3 is a halide group; L11 is a neutral electron donor ligand; L12 is a solvent molecule capable of coordination to the central metal atom M; L13 is an alkyl group; L14 is an alkyl, a carbene, a solvent molecule capable of coordination to the central metal atom M, or a halide; L{circumflex over ( )}L is a bid

Abstract: This invention relates generally to a living free radical polymerization of alkene monomers through use of persistent metal centered radicals to attain control of the propagation and termination steps in radical polymerization. This process is useful for controlling the molecular weight of homopolymers or copolymers and for forming block copolymers.