Tetrahedral and heteronuclear transition metal clusters through isolobal displacements and functional transformations

Abstract

The isolobal reaction of the tetrahedral cluster Ph2C2Co2(CO)6with η5-CHOC5H4(CO)3MNa (M = Mo, W) yields η5-CHOC5H4MCoC2Ph2(CO)5 [(1) M = Mo, (2) M = W], whereas M–M singly-bonded dimers [η5-RC5H4- M(CO)3]2 [M = Mo, R = Ac; M = Mo, W, R = CHO] react with Co2(CO)8 to give η5-AcC5H4MoCo3(CO)11(7) and η5-C5H5MCo3(CO)11 [(8) M = Mo, (9) M = W], respectively. While (1) and (2) react with 2,4-dinitrophenylhydrazine to give phenylhydrazone derivatives η5-2,4-(NO2)2C6H3NHN=CHC5H4MCoC2Ph2(CO)5 [(3) M = Mo, (4) M = W], treatment of η5-AcC5H4MCoFe(CO)8(μ3-S) with 2,4-dinitrophenylhydrazine produces corresponding derivatives η5-2,4-(NO2)2C6H3NHN=C(Me)C5H4MCoFe(CO)8(μ3-S) [(5) M = Mo, (6) M = W]. In addition, the cyclopentadienylformaldehyde ligand in the η5-CHOC5H4MoCoFe(CO)8(μ3-S) cluster can be decarbonylated in the presence of Co2(CO)8 to give the parent cluster η5-C5H5MoCoFe(CO)8(μ3-S)(10). This observation, together with the formation of (8) and (9) in the presence of Co2(CO)8 can be explained by the proposed mechanism.