Hetero- and homobimetallic M/Ni, M/M (M = Mo, W) μ-alkyne complexes containing functionally substituted cyclopentadienyl ligands. Crystal structure of η5-2,4-(NO2)2C6H3NHNC(Me)C5H4(CO)2WFe2H(μ3-S)(CO)6

While reaction of [η5-RC5H4(CO)3Mo]2, PhC≡CPh and Cp2Ni yields Mo/Ni hetero- and Mo/Mo homobimetallic complexes [η5-RC5H4(CO)2MoNiCp](μ-C2Ph2) [(1a) R = MeCO; (1b) R = MeO2C] and [η5-RC5H4(CO)2Mo]2(μ-C2Ph2) [(2a) R = MeCO; (2b) R = MeO2C], reaction of [η5-RC5H4(CO)3W]2, PhC≡CPh and Cp2Ni give W/Ni heterobimetallic compounds [η5-RC5H4(CO)2WNiCp](μ-C2Ph2) [(3a) R = MeCO; (3b) R = EtO2C] without an appreciable amount of W/W homobimetallic complexes [η5-RC5H4(CO)2W]2(μ-C2Ph2) [(4a) R = MeCO; (4b) R = EtO2C]. However, (4a) and (4b) can be simply obtained from [η5-RC5H4(CO)3W]2 and PhC≡CPh in quite good yields. Further, reactions of (1a) and (3a) with 2,4-(NO2)2C6H3NHNH2 produce phenylhydrazone derivatives [η5-2,4-(NO2)2C6H3NHNC(Me)C5H4(CO)2MNiCp](μ-C2Ph2) [(5a) M = Mo, (5b) M = W], whereas reactions of (2a) and (4a) with 2,4-(NO2)2C6H3NHNH2 give corresponding derivatives [η5-2,4-(NO2)2C6H3NHNC(Me)C5H4(CO)2MM(CO)2C5H4COMe-η5](μ-C2Ph2) [(6a) M = Mo, (6b) M = W] and [η5-2, 4-(NO2)2C6H3NHNC(Me)C5H4(CO)2M]2(μ-C2 Ph2) [(7a) M = Mo, (7b) M = W]. The crystal structure of η5-2,4-(NO2)2C6H3NHNC(Me)C5H4(CO)2WFe2H (μ3-S)(CO)6(8) has been determined by X-ray diffraction.