TRANSITION-METAL-SUBSTITUTED ACYLPHOSPHANES AND PHOSPHAALKENES .21. ISOPHOSPHAALKYNES AS MU(3)-LIGANDS IN TRANSITION-METAL COMPLEXES

Reaction of the mu-isophosphaalkyne complex (eta5-C5H5)2 (CO)2(mu-CO)Fe2(mu-CPMes) (Mes = 2,4,6-Me3C6H2) (2a) with [(Z)-Cyclooctene]Cr(CO)5 or Fe2(CO)9 gives rise to the mu3-isophosphaalkyne complexes (eta5-C5H5)2(CO)2(mu-CO)Fe2 [mu-CP[M(CO)n]Mes) 3a [M(CO)n = Cr(CO)51 and 4a [M(CO)n = Fe(CO)41. Similarly (eta5-C5H5)2(CO)2(mu-CO)Fe2{mu-CP[Cr (CO)5]C6H2(CF3)3-2,4,6) (3d) is obtained. The metal carbonyl fragments are attached to 2 in a eta1-fashion by the lone-pair at the phosphorus. In contrast to this the treatment of 2a with (Ph3P)2Pt(eta2-C2H4) affords complex 5a in which 2a serves as an eta3-3e ligand towards the PtPPh3 moiety. The molecular structures of 3a and 5a are determined by single-crystal X-ray analysis.