CONSECUTIVE C-C BOND SCISSION OF AN ALLYL LIGAND ON A WOS3 CLUSTER FRAMEWORK

Abstract

The reaction, of Os-3(CO)(9)(C(2)R(2)) (R = Tol, Ph; Tol = p-C(6)H(4)Me) with Cp(CO)(2)W=CTol (Cp = eta(5)-C5H5) produces an alkylidyne-alkyne complex CpWOs(3)(CO)(10)(mu(3)-eta(2)-C(2)R(2))(mu(3)-CTol) [1a (R = Tol), 1b (R = Ph)], which is converted to two isomeric allyl complexes CpWOs(3)(CO)(10)(mu(3)-C(3)R(2)Tol) (2a,b and 3a,b) upon thermolysis. Complexes 3a,b, in which the allyl ligand is pi-coordinated to the tungsten atom, undergo consecutive allyl C-C bond cleavage to afford trialkylidyne complexes CpWOs(3)(CO)(9)(mu(3)-CR)(2)(mu 3-CTol) (5a,b) via alkylidyne-alkyne complex CpWOs(3)(CO)(10)(mu(3)-eta(2)-C(2)R(2))(mu(3)-CTol) or CpWOs(3)(Co)(10)(mu 3-eta(2)-C(2)RTol)(mu(3)-CR) (4a,b), together with formation of CpWOs(3)(CO)(8)(mu(3)-perpendicular to-C(2)R(2))(mu(3)-CTol) or CpWOs(3)(CO)(8)(mu(3)-eta(2)-perpendicular to-C(2)RTol)(mu(3)-CR) (6a,b) as a minor product.