TRIPHENYLPHOSPHANE CHALCOGENIDES AS SELECTIVE REAGENTS FOR CONSTRUCTION OF MU-3-CHALCOGEN-BRIDGED IRON CARBONYL CLUSTERS

Irradiation of the tetrahedral clusters Fe3(CO)10(mu3-P(t)Bu), 1, in t he presence of Ph3PX (X = S, Se) leads to the formation of the square- pyramidal clusters Fe3(CO)9(mu3-P(t)Bu)(mu3-X) (2a: X = S; 2b: X = Se) and Fe3(CO)8(PPh3)(mu3-P(t)Bu)(mu3-X) (3a: X = S; 3b: X = Se). In thi s reaction the Ph3PX-ligands are split into a mu3-X-fragment as well a s a PPh3-ligand, which are both integrated into the product clusters. In addition Fe3(CO)9(PPh3)(mu3-P(t)Bu), 5, a substitution product of t he starting cluster 1, is isolated. During the reaction of 1 with Ph3P Se the cluster Fe3(CO)7(PPh3)2(mu3-P(t)Bu)(mu3-Se), 4, is formed as a further product.