Carbonyl substitution reactions of ruthenium cluster complexes containing dicarbon (C2) ligands:: X-ray structures of Ru5(μ5-C2)(μ-SMe)2(μ-PPh2)2(CO)10(L) [L=CNBut, P(OMe)3]

Addition of Bu'NC to Ru-5(mu(5)-C-2)(mu-SMe)(2)(mu-PPh2)(2)(CO)(11) (I) gives Ru-5(mu(5)-C-2)(mu-SMe)(2)(mu -PPh2)(2)(CO)(11)(CNBu') (3), in which the Ru, pentagon has become flattened, with Ru-Ru separations longer on average by 0.08 Angstrom. On heating, loss of CO restores the cluster geometry in Ru-5(mu(5)-C-2)(mu-SMe)(2)(mu-PPh2)(2)(CO)(10)(CNBu') (2) to that of i. Reactions between 1 and MeCN/Me3NO afforded the lightly-stabilised cluster Ru-5(mu(5)-C-2)(mu-SMe)(2)(mu-PPh2)(2)(CO)(10)(NCMe) (4). In a similar manner Ru-6(mu(6)-C-2)(mu-PPh2)(2)(mu(3)-SMe)(2)(CO)(14) (5) yielded Ru-6(mu(6)-C-2)(mu-PPh2)(2)(mu(3)-SMe)(2)(CO)(13)(NCMe) (6). Displacement of MeCN by PPh3 gave Ru-5(mu(5)-C-2)(mu-SMe)(2)(mu-PPh2)(2)(CO)(10)(PR3) [R = OMe (7), Ph (8)] and Ru-6(mu(6)-C-2)(mu-PPh2)(2)(mu(3)-SMe)(2)(CO)(13)(PPh3) (10). When 4 and 6 were reacted with dppa [bis(diphenylphosphino)acetylene] the 'dumbell' clusters {Ru-5(mu(5)-C-2)(mu-SMe)(2)(mu-PPh2)(2)(CO)(10)}(2)(mu- dppa) (9) and {Ru-6(mu(6)-C-2)(mu -PPh2)(2)(mu(3)-SMe)(2)(CO)(14)}(2)(mu-dppa) (11) were formed in high yield. The structure of 7 was determined by X-ray crystallography and showed that substitution occurred at the ruthenium atom attached to the C-2 ligand by the shortest Ru-C bond. Reactions of 1 with n-butylamine afforded Ru-5(mu(5)-C-2)(mu-SMe)(2)(mu -PPh2)(2)(CO)(10)(NH2Bu) (12), but secondary and tertiary amines such as NHEt2 and NEt3 gave only the previously reported Ru-5(mu(5)-CCH2)(mu-PPh2)(2)(mu-SMe)(2)(CO)(10) (13). (C) 1998 Elsevier Science S.A. All rights reserved.