Microwave-assisted synthesis of dimolybdenum tetracarboxylates and a decanuclear osmium cluster

Microwave preparation of osmium clusters with anticancer activity; rapid syntheses of Os6(CO)18, Os3(CO)10(acetonitrile)2, and Os3(μ-H)(μ-OH)(CO)10

“…Our attempts to prepare Os 3 (CO) 10 (NCMe) 2 , 2, by extended microwave heating of Os 3 (CO) 12 in acetonitrile produced only trace amounts of the desired product, presumably due to its thermal instability. Thus it was necessary to perform a two-step procedure in which Os 3 (CO) 11 (NCMe) was generated in the first step. A report in 1981 suggested that treatment of Os 3 (CO) 11 (NCMe) with Me 3 NO in acetonitrile resulted in conversion to Os 3 (CO) 10 (NCMe) 2 , but the experimental details were sketchy and no yield was given [29].…”

“…Thus it was necessary to perform a two-step procedure in which Os 3 (CO) 11 (NCMe) was generated in the first step. A report in 1981 suggested that treatment of Os 3 (CO) 11 (NCMe) with Me 3 NO in acetonitrile resulted in conversion to Os 3 (CO) 10 (NCMe) 2 , but the experimental details were sketchy and no yield was given [29]. We determined that it is possible to produce cluster 2 in 91% yield by heating a mixture of Os 3 (CO) 12 and acetonitrile in a microwave reactor followed by the addition of a Me 3 NO/MeCN solution in air at room temperature.…”

“…It is particularly noteworthy that cluster 4 is produced in minutes instead of days or weeks. Due to its thermal instability, cluster 2 cannot be synthesized directly from Os 3 (CO) 12 in a microwave reactor, but must be prepared from Os 3 (CO) 11 (NCMe) at room temperature instead. We have shown that it is not necessary to carry out this synthesis under an inert atmosphere.…”

“…It usually offers several advantages over traditional methods including shorter reaction times, lower energy costs and less solvent usage. In the last few years, microwave heating has been used for the high-yield conversion of Os 3 (CO) 12 to several other osmium clusters in a fraction of the time required by conventional heating [11,12]. Leadbeater and Shoemaker reported the fast and efficient synthesis of cluster 1 in a microwave reactor [13].…”

Efficient microwave syntheses of the compounds Os3(CO)11L, L=NCMe, py, PPh3

“…The reaction of Os 3 (CO) 12 with H 2 in a microwave reactor results in the nearly quantitative production of H 2 Os 3 (CO) 10 in only 15 min [20], while the high-nuclearity cluster anion [Os 10 C(CO) 24 ] 2À is prepared directly from Os 3 (CO) 12 with microwave heating of a diglyme solution for just over 1 h [21]. We wondered whether substitution of one or more CO ligands with MeCN ligands might be possible in a microwave reactor without the use of Me 3 NO as a decarbonylation reagent.…”