151344-35-3Relevant academic research and scientific papers
Alkyne-alkyne coupling reactions with W(CO)(PhC≡CPh)3 and W(NCMe)(PhC≡CPh)3
Yeh, Wen-Yann,Ho, Chi-Lin,Chiang, Michael Y.,Chen, I.-Ting
, p. 2698 - 2708 (2008/10/08)
Heating W(CO)(PhC≡CPh)3 (1) and diphenylacetylene in a sealed tube leads to alkyne-alkyne coupling to yield W(CO)(PhC≡CPh)2(η4C4Ph4) (2), W(CO)(PhC≡CPh)(η5-C3Ph3(C 5Ph5)) (3), and W(CO)(PhC≡CPh)(η6-C3Ph3(C 5Ph5)) (4) together with the tungstenocene oligomer [W(C5Ph5)2]x (5). Oxidation of 5 by diiodine affords W(η5-C5Ph5)2(I)2 (6), which is converted into the oxo complex W(η5-C5Ph5)2(=O) (7) by treating with AgBF4 in wet dichloromethane solution. Reaction of W(NCMe)(PhC≡CPh)a (8) and 1 equiv of diphenylacetylene produces W(NCMe)(PhC≡CPh)2(η4-C4Ph 4) (9), whereas a similar reaction in the presence of excess diphenylacetylene gives mainly the metallacyclic complex W(PhC≡CPh)(η8-C8Ph8), (10). Compound 10 reacts with carbon monoxide to afford 3 and 4, while thermolysis of pure 10 results in 5 exclusively. The reaction mechanism has been explored by C-13 labeling experiments. The structures of 7 and 10 have been established by an X-ray diffraction study. The bonding of pentaphenylcyclopentadienyl ligands of 7 is best described as a localized η3:η2 fashion. Compound 10 contains a tungstenacyclononapentaene ring with two tungstencarbon double bonds.
