Wayne Tikkanen

Zirconocene complexes of the sterically demanding pentaphenylcyclopentadienyl ligand, CpPRO. Synthesis and characterization of CpPROZrCl3 and CpCpPROZrCl2 (Cp=η5-C5H5; CpPRO=η5-C5(C6H5)5)

Abstract The synthesis, characterization and X-ray structures of two zirconium complexes of the bulky pentaphenylcyclopentadienyl ligand, CpPRO, are reported. The monocyclopentadienyl 12 electron complex, CpPROZrCl3 (I), has an unusual monomeric structure in the solid state and has short Zr–ligand distances. The Lewis acidity of this complex is manifested in its ability to catalyze the [4+2] cycloadditions of methyl- and ethylmethacrylate to cyclopentadiene. The sandwich complex, CpPROCpZrCl2 (II), has more typical Zr–ligand distances, but has a more parallel arrangement of the two cyclopentadienyl rings.

Synthesis, characterization and structures of zirconocene complexes of sterically demanding pentaphenylcyclopentadienyl and tetraphenyl-m-tolyl cyclopentadienyl ligands

The synthesis, characterization and catalytic activity of zirconium complexes containing bulky pentaarylcyclopentadienyl ligands are reported. The monocyclopentadienyl 12-electron complex, trichloropentaphenylcyclopentadienylzirconium(IV), C5Ph5ZrCl3 (I), has an unusual monomeric structure in the solid state and has short Zr–ligand distances suggesting that the complex has significant Lewis acidity. The phenyl rings adopt a propeller arrangement in the solid state; VT 1H-NMR measurements of the analogous trichloro(tetraphenyl-m-tolylcyclopentadienyl)zirconium(IV) (II) indicate that there is rapid rotational motion of the phenyl rings. The Lewis acidity of this complex is manifested in its ability to catalyze the [4+2] cycloadditions of acrolein and methyl acrylate to cyclopentadiene. The sandwich complex, C5Ph5CpZrCl2 (III), has more typical Zr–ligand distances, but has a more parallel arrangement of the two cyclopentadienyl rings and does not display the reactivity shown by I and II.

Preparation, characterization and carbonylation of the ring-functionalized dibenzyl zirconocenes, (η5-C5H5)x((η5-C5H4)P(C6H5)2)2−xZr(CH2C6 H5)2 (x = 1, (1); x = 0, (2))

Abstract The preparation, characterization and carbonylation products of the ring-functionalized alkyl zirconocenes, ( η 5 C 5 H 5 )( η 5 -C 5 H 4 -P(C 6 H 5 ) 2 Zr(CH 2 C 6 H 5 ) 2 ( 1 ), ( η 5 -C 5 H 4 -P(C 6 H 5 ) 2 ) 2 Zr(CH 2 C 6 H 5 ) 2 ( 2 ) are described. These compounds insert one molecule of CO to give products which interconvert between an acyl form and a phosphonium-alkoxide form at ambient temperatures via a reversible nucleophilic attack of the phosphine at the carbenium-like η 2 -acyl carbon as shown through the variable-temperature 1 H and 31 P{ 1 H} NMR studies.

Preparation and Characterisation of TiO2-Supported on the Surface of SiO2

A surface TiO2-supported of silica composite material was prepared by surface organometallic chemistry method and the structure was characterized by FTIR, EDAX and XRD. The results show the bonding interaction between TiO2 and SiO2, linking by Si-O-Ti bond. Furthermore, the anatase phase crystal structure is observed by XRD analysis.