M. D. Fryzuk, Paul B. Duval, and Brian O. Patrick
Mar 14, 2001
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Journal
Organometallics
Abstract
The synthesis, structural characterization, and solution behavior of hafnium complexes stabilized by the potentially tridentate ancillary ligand [P2Cp] ([P2Cp] = (η5-C5H3-1,3-(SiMe2CH2PPri2)2)) are described. The reaction of [P2Cp]Li with HfCl4(THT)2 produces the hafnium trichloride complex [P2Cp]HfCl3 (1), the structure of which was determined by X-ray crystallography. Trichloride 1 is isostructural with the analogous zirconium complex [P2Cp]ZrCl3 (2) in the solid state, but in solution 1 exists as an equilibrium mixture of two isomers that interconvert by fluxional phosphine coordination. Treatment of 1 with 2 equiv of KCH2Ph, followed by thermolysis, yields the first structurally characterized hafnium alkylidene complex, [P2Cp]HfCHPh(Cl) (3). A crystal structure determination obtained for 3 shows this complex to be isostructural with the zirconium analogue [P2Cp]ZrCHR(Cl) (4). The primary difference between the Hf systems presented here and the previously studied Zr analogues is that metal−ligand bondi...