Microwave Promoted Oxidative Addition Reactions of Os(3)(CO)(12): Efficient Syntheses of Triosmium Clusters of the Type Os(3)(mu-X)(2)(CO)(10) and Os(3)(mu-H)(mu-OR)(CO)(10)

Microwave heating allows for the high-yield, one-step synthesis of the known triosmium complexes Os(3)(mu-Br)(2)(CO)(10) (1), Os(3)(mu-I)(2)(CO)(10) (2), and Os(3) (mu-H)(mu-OR)(CO)(10) with R = methyl (3), ethyl (4), isopropyl (5), n-butyl (6), and phenyl (7). In addition, the new clusters Os(3)(mu-H)(mu-OR)(CO)(10) with R = n-propyl (8), sec-butyl (9), isobutyl (10), and tert-butyl (11) are synthesized in a microwave reactor. The preparation of these complexes is easily accomplished without the need to first prepare an activated derivative of Os(3)(CO)(12), and without the need to exclude air from the reaction vessel. The syntheses of complexes 1 and 2 are carried out in less than 15 min by heating stoichiometric mixtures of Os(3)(CO)(12) and the appropriate halogen in cyclohexane. Clusters 3-6 and 8-10 are prepared by the microwave irradiation of Os(3)(CO)(12) in neat alcohols, while clusters 7 and 11 are prepared from mixtures of Os(3)(CO)(12), alcohol and 1,2-dichlorobenzene. Structural characterization of clusters 2, 4, and 5 was carried out by X-ray crystallographic analysis. High resolution X-ray crystal structures of two other oxidative addition products, Os(3)(CO)(12)I(2) (12) and Os(3)(mu-H)(mu-O(2)CC(6)H(5))(CO)(10) (13), are also presented.