Reactions of Cyclotetradeca-1,8-diyne with Triosmium Carbonyl Clusters

Reaction of Os3(CO)10(NCMe)2 and cyclotetradeca-1,8-diyne (C14H20) affords the alkyne complexes Os3(CO)10(μ3-η2-C14H20) (1) and (Os3(CO)10)2(μ3,μ3-η2,η2-C14H20) (2). Thermolysis of 1 results in a C−H bond activation to give the hydrido allene complex (μ-H)Os3(CO)9(μ3-η3-C14H19) (3). Photoirradiation of 1 in the presence of C14H20 ligand produces the metallacyclopentadienyl complex Os3(CO)9(μ-η4-C4(C12H20)2) (4). In contrast, Fe3(CO)12 reacts with C14H20 to generate Fe3(CO)9(μ3-η2-C14H20) (5), which upon heating undergoes cluster fragmentation to give the known complexes (η4-C4(C10H20))Fe(CO)3 and [(η5-C5(C9H18))Fe(CO)2]2. The new compounds 1−5 have been characterized by mass, IR, and NMR spectroscopy. The structures of 2−4 have been determined by an X-ray diffraction study.