Zirconocene and rac-[1,2-ethylene-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

摘要

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)-tetrahydroindenyl)) with 2-vinylpyridine lead, under elimination of the alkyne, to the five-membered azazirconacycles, which are best described as 1-zircona-2-azacyclopent-3-enes (1-azadiene complexes). One of these complexes couples with ethylene to yield a stable alpha-2-pyridyl-substituted zirconacyclopentane and reacts in a 2:1 ratio with water to yield a beta-2-pyridyl-substituted dimeric sigma-ethylzirconoxane. In the reaction of the 2-derived complex with HBF4, rac-[1,2-ethylene-1,1'-bis(eta(5)-tetrahydroindenyl)]zirconium difluoride was obtained. Both 1-zircona-2-azacyclopent-3-enes insert carbon dioxide to give structurally different binuclear carbonate-bridged complexes. [References: 34]