Structural and chemical aspects of electron deficient pentamethylcyclopentadienyltitanium halides, alkyls, and oxides

Abstract

We were interested in electron deficient organotitanium complexes das potential Ziegler-Natta catalysts likely to show particularly interesting structural features and easily accessible low valent oxidation states and so we chose pentamethylcyclopentadienyltitanium trichloride as the starting product for our studiesThe research described here is included in Project PR-84-0407 financially sup­\ud ported by CAICYT and sponsored by Repsol Petr6leo. We are also indebted to S. Martinez \ud Carreras and S. Garcia Blanco of the Departamento de Cristalografia CSIC (Madrid), and \ud to Prof. A. Tiripicchio of the Centro di Studio per la Strutturistica \ud Diffrattometrica de!CNR de la Universita di Parma (Italy) for determination of the \ud X-ray structures. Our excellent co-workers J.C. Flores, F. Palacios and Dra. I. Saez \ud carried out some of the experimental work described here and their collaboration is warmly \ud acknowledged

Simple Synthesis of (Triphenylphosphoniomethylidene)(pentamethylcyclopentadienyl)titanium(II) Dichloride and Its Unexpected Reduction To Form a Trinuclear Titanium Cluster

“…The average distance of Ti−Cl bridged (1.831 Å) is much shorter than that of Ti−Cl terminal (2.286 Å). The Ti−Ti distances, 3.371 Å, are consistent with the values of 3.35 Å found in [Cp*TiCl(μ-O)] 3 , 3.34 Å in [Cp*TiMe(μ-O)] 3 , and 3.438 Å in [TiCl 2 (μ-Cl)(dippe)] 2 …”

An investigation of catalyst/cocatalyst/support interactions in silica-supported olefin polymerization catalysts based on Cp*TiMe3*

“…After desorption of unreacted starting material, hydrolysis of 1 by exposure to water vapor resulted in the liberation of 1.9 ± 0.1 MeH/Ti, confirming that 1 retains two methyl ligands. The formation of silicasupported Cp*Ti IV Me 2 fragments is analogous to the protonolysis of Cp*TiMe 3 by bulky alcohols [24] and silanols [26]. In solution, steric bulk limits the extent of methyl substitution, while the distance between neighboring surface hydroxyls and the rigidity of the silica ''ligand'' prohibit additional protonolytic reactions on the silica surface.…”

Cyclopentadienyl−Hydrazido Titanium Complexes: Tuning of Coordination Modes of Hydrazido Ligands to the Titanium Center

“…The coordination geometry of each Ti atom is pseudo-tetrahedral with three sites being occupied by bridging oxygen atoms and the remaining site by a π-bonded η 5 -tetramethyl cyclopentadienyl ligand with a hydrazidodimethylsilyl substituent. Compound 6 is likely to be formed by similar hydrolysis and condensation reaction proposed for the formation of [(η 5 -C 5 Me 5 )Ti] 4 O 6 from hydrolysis of (η 5 -C 5 Me 5 )TiCl 3 under basic conditions 3 Molecular structure of 6 .…”