Oxidative addition reactions of benzo[b]thiophene and dibenzothiophene with [Os3(CO)10(MeCN)2]:: room-temperature ring opening of benzo[b]thiophene at triosmium clusters

Reaction of the cluster [Os-3(CO)(10)(MeCN)(2)] with benzo[b]thiophene (C8H6S) leads to the hydridic decacarbonyl and nonacarbonyl species [Os-3(mu-H)(CO)(10)(mu-C8H5S)] (1) and [Os-3(mu-H)(2)(CO)(9)(mu(3)-C8H4S)] (2), formed by cleavage of one and two C-H bonds respectively. In addition, the decacarbonyl complex [Os-3(CO)(10)(mu-C8H6S)] (3) is formed by C-S bond cleavage. Thermal treatment of compound 1 affords clusters 2 and 3 in good yields, and at room temperature the slow, clean and complete conversion of 1 into 3 is observed. From dibenzothiophene (C12H8S), [Os-3(mu-H)(2)(CO)(9)(mu(3)-C12H6S)] (4) is obtained by C-H bond cleavage at one benzo group and its structure has been established by X-ray crystallography. The organic ligand is bonded through sigma-Os-C bonds to two Os atoms and an eta(2)-contact with the third, and the C-C bond between the two metal-bonded carbon atoms lies essentially parallel to one Os-Os bond. (C) 1999 Elsevier Science S.A. All rights reserved.