Syntheses of double- and triple-decker clusters of osmium and cobalt metals linked by cyclotetradeca-1,8-diyne ligands

Photoirradiation of Os3(CO)10(C14H20) (1) in n-hexane produces the double-decker cluster [Os3(CO)9(C28H40)] [Os3(CO)10] (7), which can also be prepared from the reaction of Os3(CO)9(C28H40) (2) and Os3(CO)10(NCMe)2. Further reaction of 7 with Os3(CO)10(NCMe)2 affords the triple-decker cluster [Os3(CO)9(C28H40)][Os3(CO)10]2 (8). The bis(diyne) complex Os3(CO)8(C14H20)2 (3) reacts with Os3(CO)10(NCMe)2 sequentially to yield the double-decker cluster [Os3(CO)8(C14H20)2][Os3(CO)10] (4) and the triple-decker cluster [Os3(CO)8(C14H20)2][Os3(CO)10]2 (5). Treatment of 3 with Co2(CO)8 at room temperature leads to the mixed-metal triple-decker cluster [Os3(CO)8(C14H20)2][Co2(CO)6]2 (6), while the reaction of 2 and Co2(CO)8 produces [Os3(CO)9(C28H40)][Co2(CO)6]2 (9) and [Os2(CO)6(C28H40)][Co2(CO)6]2 (10). Compound 10, which involves cluster degradation from Os3 to Os2, has been structurally characterized by an X-ray diffraction study.