Supported olefin polymerization catalysts can prevent reactor-fouling problems and produce uniform polymer particles. Constrained geometry complexes (CGCs) have less sterically hindered active sites than bis-cyclopentadienyl metallocene catalysts. In the literature, micrometer-sized silica particles were used for supporting CGC catalysts, which might have strong mass transfer limitations. This ...

50 years ago, Karl Ziegler and Giulio Natta were awarded the Nobel Prize for their discovery of the catalytic polymerization of ethylene and propylene using titanium compounds and aluminum-alkyls as co-catalysts. Polyolefins have grown to become one of the biggest of all produced polymers. New metallocene/methylaluminoxane (MAO) catalysts open the possibility to synthesize polymers with highly ...

Monoand bis(q-cyclopentadieny1)zirconium complexes show interesting stereochemical features with regard to their use in organometallic and organic synthesis as well as in catalysis. An example is described where the zirconocene unit serves to stabilize a planar tetracoordinate carbon center. Next, various building blocks (a metal carbonyl, an organic carbonyl compound, a conjugated diene, plus ...

Title of Document: KINETICS AND MORPHOLOGY OF METALLOCENE CATALYZED SYNDIOSPECIFIC POLYMERIZATION OF STYRENE IN HOMOGENEOUS AND HETEROGENEOUS REACTION SYSTEMS Joong Jin Han, Doctor of Philosophy, 2008 Directed By: Professor Kyu Yong Choi Department of Chemical and Biomolecular Engineering Syndiotactic polystyrene (sPS) is a semicrystalline thermoplastic polymer with many advantageous properties...

The purpose of this paper is to summarize mode of action of cisplatin on the tumor cells, a brief outlook on the metallocene compounds as antitumor drugs as well as the future tendencies for the use of the latter in anticancer chemotherapy. Molecular mechanisms of cisplatin interaction with DNA, DNA repair mechanisms, and cellular proteins are discussed. Molecular background of the sensitivity ...

The reactions of (eta(5) - C(5)H(5))(2)MCl(2) (M = Ti, Zr, or Hf) with mercaptoazoles (LH(2)), namely, bis(mercaptotriazoles), bis(mercap- tooxadiazoles), and bis(mercaptothiadiazoles) in 2 : 1 molar ratio, respectively, have been studied in dry tetrahydrofuran in the presence of n-butylamine and the binuclear complexes of the type [{(eta - C(5)H(5))(2) M}(2)(L)] (M = Ti/Zr/Hf) are obtained. Te...