(2-Diphenylphosphinoethyl)cyclopentadienyl complexes of zirconium (IV): Synthesis, crystal structure and dynamic behaviour in solutions

Abstract The novel [η5:η1-(2-diphenylphosphinoethyl)cyclopentadienyl]trichlorozirconium (IV) 3 has been prepared via (2-diphenylphosphinoethyl)(trimethylsilyl)cyclopentadiene 2. The structures of an adduct of 3 with tetrahydrofuran (THF) 3b (two crystal modifications) and of an ionic complex derived from 3 and ZrCl4 {[η5:η1−(C5H4CH2CH2PPh2)ZrCl]2(μ−Cl)3}+2[(ZrCl4)2(μ−Cl)2]2− 4 have been determined by an X-ray analysis. The X-ray and NMR data prove the existence of a Zr–P intramolecular coordination in 3 both in solid state and in non-solvating media within a broad range of temperatures. In THF solution the flexible equilibrium between adducts of 3 with one (3b) and two (3c) molecules of THF has been observed by variable-temperature NMR spectroscopy. The synthetic route to the simplest unsymmetrically ligated zirconocene (η5-C5H4CH2 CH2PPh2)(η5-C5H5)ZrCl2 5 derived from 3 has also been elaborated.