ZIRCONOCENE AND YLENE-1,1'-BIS(ETA(5)-TETRAHYDROINDENYL)]ZIRCONIUM COMPLEXES OF 2-VINYLPYRIDINE - SYNTHESES, X-RAY CRYSTAL-STRUCTURES, AND REACTIONS WITH H2C=CH2, H2O, HBF4, AND CO2

Reactions of Cp2Zr(thf)(eta(2)-Me3SiC2SiMe3) (1) and rac-(ebthi)Zr(eta (2)-Me3SiC2SiMe3) (2; ebthi = 1,2-ethylene-1,1'-bis(eta(5)-tetrahydroi ndenyl)) with 2-vinylpyridine lead, under elimination of the alkyne, t o the five-membered azazirconacycles, which are best described as 1-zi rcona-2-azacyclopent-3-enes (1-azadiene complexes). One of these compl exes couples with ethylene to yield a stable alpha-2-pyridyl-substitut ed zirconacyclopentane and reacts in a 2:1 ratio with water to yield a beta-2-pyridyl-substituted dimeric sigma-ethylzirconoxane. In the rea ction of the 2-derived complex with HBF4, ylene-1,1'-bis(eta(5)-tetrah ydroindenyl)]zirconium difluoride was obtained. Both 1-zircona-2-azacy clopent-3-enes insert carbon dioxide to give structurally different bi nuclear carbonate-bridged complexes.