Syntheses, structures and electrochemical study of π-acetylene complexes of cobalt

The preparation and characterisation of the complexes [Co2(CO)4(PMe3)2][Co2(CO)6](Me3SiC2C2SiMe3) (4), [Co2(CO)4(dppm)][Co2(CO)6](Me3SiC2C2H) (5), [Co2(CO)4(dppa)][Co2(CO)6](Me3SiC2C2SiMe3) (6), [Co2(CO)4(dppm)]2[Co2(CO)6](Me3SiC2CCC2C2SiMe3) (7) and [{SiMe3(Co2(CO)4(dppm))C2}2(HCC)(1,3,5-C6H3)] (8) are described. An electrochemical study of the complexes 5–8 and of the related [Co2(CO)4(dppm)]2(Me3SiC2(CC)2C2SiMe3) (1), [Co2(CO)4(dppa)]2(Me3SiC2C2SiMe3) (2) and [{SiMe3(Co2(CO)4(dppm))C2}(HCC)2(1,3,5-C6H3)] (3) is presented by means of the cyclic and square-wave voltammetry techniques. Crystals of 8 suitable for single-crystal X-ray diffraction were grown and the molecular structure of this compound is discussed.