Substitution reactions of dinuclear alkenyl-bridged iron-cobalt complexes with alkynylphosphines and diphosphines

Reaction of [(CO)3FeCo(CO)3](μ-C(CO2Me= = CH(CO2Me) (1) with Ph2PCCR produces: (i) mono-substituted [(Ph2PCCR)(CO)2FeCo(CO)3](μ-C(CO2Me)=CH(CO2Me (R=Me (4), Ph (6), tBu (8)) and [(CO)3FeCo(CO)2-(Ph2PCCR)](μ-C(CO)2Me) =CH(CO2Me) (R=Me (5), Ph (7), tBu (9), H (10)) and (ii) di-substituted [Ph2CCR)(CO)2-FeCo(CO)2(Ph2CCR)](μ-C(CO2Me)= CH(CO2Me) (R=Ph (11), tBu (12), H (13) FeCo complexes. Alkenyl [(CO4FeCo(CO)3](μ-CR′=CH2] (R′=CO2Me (2) or CO2Et (3)) compounds also react with phosphinoalkynes, leading to the iron-substituted [(Ph2PCCR)(CO)3FeCo(CO)3](μ-CR′=CH2) (R′=CO2Me, R=Ph (14); R′=CO2Et, R=Ph (14); R′=CO2Et, R=Me (15)) R′=CO2Et, R=Me (16)) compounds. The reaction of 1 with dppe gives a mixture of two types of product: (i) compounds 17 and 18 of formulae dppe[FeCo(CO)5(μ-(C(CO)2Me)H]2, the structure of which consists of two [FeCo(CO)5(μ-(CO2Me)=C(CO)2MeH] units bridged by a dppe ligand bonded to two Co and two Fe atoms, respectively, and (ii) compound 19 of formula dppe[FeCo(CO)4(μ-(CO2Me)=C(CO2Me)H], in which the dppe ligand bridges the FeCo bond. Reaction with dppm produces dppm[FeCo(CO)5(μ-(CO2Me)H]2 (20) and [FeCo(CO)5(μ-(CO2Me= C(CO)2MeH] (21), the structures of which are similar to those of compounds 17 and 19. The monosubstituted phosphinoalkyne FeCo complexes react with Co2(CO)8 to form a new family of products [(Co)2(CO)6(μ-Ph2PCCR)) [FeCo(CO)5((μ-(CO2Me=C(CO2Me)H) (22-26), which contain the Co2(CO)6 fragment coordinated to the CC bond of the phosphine ligand. © 1995.