Some Novel Coordination Compounds of Group IV Metals

Abstract

In investigations to determine whether ligand groups can be added directly to the lower halides of zirconium and titanium it has been found that cyclopentadiene vapour reacts with these compounds at 200 – 300° to put a C5H5 ring in each of the vacant valency positions according to the reaction: Open image in new window with the hydrogen apparently reacting with excess cyclopentadiene. From the appropriate lower halides the previously undescribed compounds C5H5ZrBr3, C5H5ZrBr3 and C5H5ZrI3 and the known compounds (C5H5)2ZrCl2, (C5H5)2ZrBr2 and C5H5TiCl3 were made. The known compounds had physical properties and X-ray powder patterns identical with samples made by other routes. The zirconium trihalogeno -compounds were also synthesized by the action of magnesium cyclopentadienide in xylene solution on zirconium tetrahalides, and these compounds were identical with those from the lower halides reactions. In all cases a single sharp proton magnetic resonance peak was obtained from the compounds in solution, showing them to contain π -bonded C5H5 rings. This was confirmed by the near infra-red reflectance spectra of the solids (1), which correspond closely with that of ferrocene.