Mika Polamo

Syntheses and crystal structures of phenyl(2-pyridyl)amido complexes of zirconium(IV), niobium(V) and tantalum(V)

Di-µ-chloro-dichlorotetrakis[phenyl(2-pyridyl)amido]dizirconium(IV), trichlorobis[phenyl(2-pyridyl)amido]niobium(V) and trichlorobis[phenyl(2-pyridyl)amido]tantalum(V) have been synthesized in a direct reaction between 2-(phenylamino)pyridine and the appropriate metal halide under reflux in toluene. The use of butyllithium was rejected because of the formation of the unreactive ligand adduct bis[2-(phenylamino)pyridine]bis[phenyl(2-pyridyl)amido]dilithium. Single-crystal structures were determined for all four compounds. The niobium and tantalum complexes are monomeric in the solid state, whereas the zirconium complex is a dimer with two bridging chloride ligands. The amide is didentate with one σ- and one π-donor bond. The chelate rings formed have narrow N–M–N angles, around 60°. The co-ordination spheres around the transition metals are pseudo-pentagonal bipyramids.

Phenoxy substituted zirconocenes in ethylene polymerization

Abstract Zirconocene dichloride was reacted with either 2,6-di-tert-butyl- or 2,6-diisopropyl phenol to form bis(η5-cyclopentadienyl) zirconium(IV) monochloride complexes 1 and 2 respectively. A bisphenoxy derivative of Cp2ZrCl2, 3, was formed, when sterically less demanding 2,6-dimethyl phenol was utilized. The ability of the complexes 1, 2 and 3 in ethylene polymerization with MAO as cocatalyst was examined. Polymer analysis indicates that, regardless of which complex was used, only one kind of catalytically active metal center is formed and polymer properties resemble those obtained with the Cp2ZrCl2/MAO system. The solid state structure of bis(η5-cyclo-pentadienyl) zirconium(IV) 2,6-di-tert-butyl-phenoxy monochloride (1) is reported.

Metallocene dichlorides bearing acenaphthyl substituted cyclopentadienyl rings: preparation and polymerization behavior

Abstract The unbridged complex [bis(η5-7,9-diphenylcyclopenta[a]acenaphthadienyl)] zirconium dichloride (8) and two asymmetric ethylene bridged metallocenes {bis[1,2-(η5-7,9-diphenylcyclopenta[a]acenaphthadienyl)-1-phenyl] ethane} zirconium dichloride (9) and {[1-(η5-7,9-diphenylcyclopenta[a]acenaphthadienyl)-2-phenyl-2-(η5-9-fluorenyl)] ethane} zirconium dichloride (10) were prepared and used as catalysts for ethene and propene homopolymerization after activation with MAO. Whereas zirconocenes 8 and 9, that bear two acenaphthyl substituted Cp-rings, have only moderate activity, 10 produces polyethene with high activity and high molecular weight. In propene polymerization only atactic polymer was formed and the chain termination occurred mainly via β-methyl elimination. The solid state structures of compounds 8, 9 and 10 were determined by means of X-ray diffraction analysis.

A Tetrahydrofuran Ring-Opening Product: trans-Tetrachloro{4-[2-(phenylamino)pyridinio]butoxido-O}(tetrahydrofuran-O)zirconium(IV)

The title compound, [ZrCl4(C15H18N2O)(C4H8O)], was formed via tetrahydrofuran (thf) ring opening when ZrCl4 and 2-(phenylamino)pyridine were heated in a thf-containing reaction medium. The molecule is zwitterionic, with distorted octahedral coordination at the negatively charged zirconium(IV) centre. A 2-(phenylamino)pyridinium cation is connected to the metal centre by a residue formed through opening of a thf ring.

From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

The mesomeric betaine imidazolium-1-ylphenolate forms a borane adduct with tris(pentafluorophenyl)borane by coordination with the phenolate oxygen, whereas its NHC tautomer 1-(2-phenol)imidazol-2-ylidene reacts with (triphenylphosphine)gold(I) chloride to give the cationic NHC complex [Au(NHC)2][Cl] by coordination with the carbene carbon atom. The anionic N-heterocyclic carbene 1-(2-phenolate)imidazol-2-ylidene gives the complexes [K][Au(NHC−)2], [Rh(NHC−)3] and [Ni(NHC−)2], respectively. Results of four single crystal analyses are presented.

Tetrakis(diphenylamido-N)hafnium

The hafnium coordination in the monomeric title molecule, [Hf(C12H10N)4], is distorted tetrahedral, with Hf—N distances between 2.047 (4) and 2.085 (3) A, and angles between 101.63 (14) and 121.33 (14)°. One molecule forms the asymmetric unit.

Phenylimidopentachloroniobate(V) Dianion with N-Allylphenylammonium Counterion

Bis[phenyl(2-propenyl)ammonium] pentachloro(phenylimido)niobate(V), (C 9 H 12 N) 2 [NbCl 5 (C 6 H 5 N)], is a product of the reaction of niobium pentachloride and N-allylphenylamine. The coordinated secondary amine loses its allyl group and forms an imino bond to the metal. Unreacted N-allylphenylamine behaves as a proton acceptor and is a counterion in the solid state. In the crystalline state, the asymmetric unit consists of two octahedral pentachloro(phenylimido)niobate(V) dianions and four N-allylphenylammonium cations.

A 1:4 Adduct of Tetrachlorobis(μ-phenylimido)dizirconium(IV) and Tetrahydrofuran

The title complex, bis(μ-phenylimido)bis[dichlorobis(tetrahydrofuran)zinc], [Zr2Cl4(C6H5N)2(C4H8O)4], contains two octahedral ZrIV ions which are connected by two bridging phenylimino ligands. The Zr coordination polyhedra have significantly different geometries. In one, the chloro ligands are cis, while in the other they take up trans positions. Both ZrIV ions are situated on a twofold axis.

2,6-Bis(phenylamino)pyridine

The structure of the title compound, C 17 H 15 N 3 , consists of two independant molecules which are connected by nearly linear weak N(amino)-H...N(pyridine) hydrogen bonds through a pseudo center of inversion to form a dimer. Conformationally, this symmetrically substituted pyridine derivative displays an E,E form. In this form the H-atom interactions between neighboring rings are reduced

Bis(2-N,N′-methylpiperazinoindenyl)zirconium dichloride. Crystal structure of bis(2-N,N′-methylpiperazinoindenyl)ZrCl2

Abstract Synthesis of bis(2- N , N ′-methylpiperazinoindenyl)zirconium dichloride is described. The solid state structure, based on single crystal X-ray diffraction, shows that the compound has a nearly C 2 -symmetric conformation. This amino-substituted zirconium metallocene catalyst and methylaluminoxane as a cocatalyst yield polyethylene with narrow molecular weight distribution and very high activity.