Reactions of metal–metal triply bonded complexes [(η5-RC5H4)2M2(CO)4] (M=Mo, W) with diphenyl ditelluride. Crystal structures of [(η5-MeC5H4)Mo2(CO)4(μ-TePh)3] and [(η5-EtO2CC5H4)2W2(CO)4(μ-TePh)2]

Reactions of triply bonded complexes [(η5-RC5H4)2M2(CO)4] with Ph2Te2 in solution and solid state were investigated. While [(η5-RC5H4)2M2(CO)4] (M=Mo, R=H, Me3Si, MeCO; M=W, R=MeCO, MeO2C, EtO2C) reacted with Ph2Te2 in toluene at reflux to give a series of doubly bridged complexes [(η5-RC5H4)2M2(CO)4(μ-TePh)2] (1, M=Mo, R=H; 2, Mo, Me3Si; 3, Mo, MeCO; 4, W, MeCO; 5, W, MeO2C; 6, W, EtO2C), the reaction of [(η5-MeC5H4)2Mo2(CO)4] with Ph2Te2 under the same conditions produced not only the corresponding doubly bridged complex [(η5-MeC5H4)2Mo2(CO)4(μ-TePh)2] (7) but also the unexpected triply bridged complex [(η5-MeC5H4)Mo2(CO)4(μ-TePh)3] (8). For these bridged dinuclear complexes structural characterization and conformational analysis were carried out, while the crystal structures of 6 and 8, representing the two types of the structures of complexes 1–8, were successfully determined by single crystal X-ray diffraction techniques.