STRUCTURE, PROPERTIES, AND NMR SPECTROSCO PICAL CHARACTERIZATION OF CP(2)ZR(PYRIDINE)(ME(3)SIC-CSIME(3))

Displacement of the THF ligand in Cp(2)Zr(THF)(Me(3)SiC=CSiMe(3)) (1) with pyridine yields Cp(2)Zr(eta(1)-NC5H5)(Me(3)SiC=CSiMe(3)) (3). Unl ike 1, the complex 3 is stable in hydrocarbon solvents. According to t he temperature dependent H-1 and C-13 NMR spectra, the structure of co mplex 3 in solution is dynamic due to a rotation of the alkyne ligand. In addition, when 3 is dissolved in pyridine an easy exchange between coordinated and free molecules of pyridine takes place. In the solid state complex 3 displays a tetrahedral coordination sphere at the zirc onium center composed of Cp ligands, alkyne and pyridine as shown by a n X-ray structure analysis. The complex 3 reacts readily with water an d carbon dioxide giving the same products as in the case of 1.