110934-32-2Relevant academic research and scientific papers
Interaction of trialkylaluminum reagents with metal-bound ethylene and carbon monoxide. The molecular structure of (η5-C5Me5)2Ta(H)(C 2H4·AlEt3)
McDade, Christine,Gibson, Vernon C.,Santarsiero, Bernard D.,Bercaw, John E.
, p. 1 - 7 (2008/10/08)
The compounds (η5-C5Me6)2M(H) (C2H4) and (η5-C5Me5)2M(H)(CO) (M = Nb, Ta) reversibly bind trialkylaluminum reagents to give 1:1 adducts in which the aluminum is bonded to the metal-bound ethylene or carbonyl oxygen in preference to the hydride ligand. The mixed-ring compound (η5-C5Me5) (η5-C5H5)Ta(H)(CO), in contrast, binds aluminum at the hydride ligand. The nature of the interactions has been established by IR and NMR studies and by determination of the molecular structure of (η5-C5Me5)2Ta(H)(C 2H4·AlEt38) at reduced temperature [P21/c, a = 14.877 (5) A?, b = 12.455 (7) A?, c = 15.017 (4) A?, β = 101.08 (13)°, V = 2730 (2) A?3, T = 220 K, Z = 4, 2496 reflections, S (goodness-of-fit) = 2.75, 283 parameters, R = 0.054 (2033 reflections, I > 3σI)]. This structure displays an unusual ethylene bridge between the aluminum and tantalum centers. The significance of these adducts in the context of Ziegler-Natta catalysis and migratory insertion is discussed.
