Synthesis and characterization of new heterobimetallic iron–cobalt complexes with ethenyl bridges CR2CHR1[R1= H or C(O)OMe, R2= C(O)OMe or C(O)OEt]. X-Ray structure of [FeCo(CO)6{µ-MeOC(O)CC(H)C(O)OMe}]
Abstract
The reaction of [Fe(η3-R1HCCR2CO)(CO)3]–(1) with [Co2(CO)8] yields two types of new heterobimetallic Fe–Co complexes. When R1= H and R2= C(O)OMe or C(O)OEt, the products are the µ-ethenyl complexes [FeCo(CO)7(µ-R2CCH2)](2), while when R1= R2= C(O)OMe the complex [FeCo(CO)6{µ-MeOC(O)CC(H)C(O)OMe}](3) is formed. In this complex one ester group of the µ-ethenyl ligand is co-ordinated via oxygen to iron. This feature has been confirmed by a single-crystal X-ray diffraction study. The reaction of (2) and (3) with one equivalent of PMe2Ph yields the complexes (4) and (5), respectively, in which one molecule of CO has been substituted by the phosphine. The site of substitution is different in (4) and (5); thus in complexes (4) the phosphine ligand is bonded to iron but in (5) it is bonded to cobalt.