Microwave Promoted Oxidative Addition Reactions of Os3(CO)12: Efficient Syntheses of Triosmium Clusters of the Type Os3(μ-X)2(CO)10 and Os3(μ-H)(μ-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-O2CC6H5)(CO)(10) (13), are also presented.