Reactions of various organotitanium compounds with potentially bidentate alkenyloxo- and related ligands

Abstract

Monoalkoxo-derivatives of titanium(IV) have been synthesised from the potentially bidentate ligand but-3-en-1-ol as four-co-ordinate monomers : [TiCl₃(OCH₂CH₂CHCH₂)], (I); [(cp)₂TiCl(OCH₂CH₂CHCH₂)], (II); and [(cp)₂TiMe(OCH₂CH₂CHCH₂)], (III)(cp =η-cyclopentadienyl). The 1 : 1 complex of titanium tetrachloride and 4-methoxybut-1-ene is a chloro-bridged dimer containing six-co-ordinate titanium, {TiCl₄(MeOCH₂CH₂CHCH₂)}₂(IV). A variation in the chemical shifts of the olefinic protons in complex (IV), and in (I) and its six-co-ordinate derivatives, has been observed in n.m.r. spectra but it is not considered to be sufficient to imply titanium–olefin bonding. Attempts to prepare models of Ziegler–Natta catalysts by methylation of these compounds have not been successful. Brief reports of reactions of dimethyltitanium dichioride with some uni- and bi-dentate ligands are also given.