Synthesis, characterization and reactions of ethylene complexes bearing Ta(η5-C5R5)(η4-buta-1,3-diene) fragments (R = H, Me)
作者:Kazushi Mashima、Yoshiyuki Tanaka、Akira Nakamura
DOI:10.1016/0022-328x(95)05638-6
日期:1995.10
The ethylene complex TaCp(eta(4)-butadiene)(eta(2)-C2H4)(PMe(3)) (2) was prepared in 77% yield by the reaction of TaCl(2)Cp(eta(4)-butadiene) (la) with 2 equiv. of EtMgI in the presence of 1 equiv. of PMe(3). In the absence of PMe(3), TaCp(eta(4)-butadiene)(eta(2)-C2H4) (3) was initially formed but this gradually decomposed to give the known metallacyclic compound Ta(CH2CH2CH2CH2)Cp(eta(4)-butadiene) (4). Carbonylation of 2 afforded a monocarbonyl complex TaCp(butadiene)(CO)(PMe(3)) (6) and a dicarbonyl complex TaCp(butadiene)(CO)(2) (7), while reaction of 2 with diphenylacetylene under UV irradiation gave a reversible addition product TaCp(eta(4)-butadiene)(eta(2)-PhC=CPh)(PMe(3)) (8).