PREPARATION AND SPECTROSCOPIC PROPERTIES OF A SERIES OF NEW BIMETALLIC PHOSPHINE-BRIDGED 7-COORDINATE COMPLEXES OF THE TYPE [M2I4(CO)6L2(MU-LL)] (M = MO OR W, L = PPH3, ASPH3 OR SBPH3, LL = PH2P(CH2)NPPH2 (N=1, 2 OR 4), LL = [FE(ETA-5-C5H4PPH2)2])

Reaction of the complexes [MI2(CO)3(NCMe)2] (M = Mo or W) with one equivalent of L(L = PPh3, AsPh3 or SbPh3) in CH2Cl2 at room temperature gives [MI2(CO)3(NCMe)L], which when treated in situ with half an equivalent of LL {LL = Ph2P(CH2)nPPh2, n = 1, 2 or 4; LL [Fe(eta-5-C5H4PPh2)2]} affords the new bimetallic seven-coordinate complexes [M2I4(CO),L2(mu-LL)] in high yield. P-31 NMR studies suggest that reaction of [WI2(CO)3(NCMe)(AsPh3)] with an equimolar amount of Ph2P(CH2)4PPh2 gives a mixture of [W2I4(CO)6(AsPh3)2{mu-Ph2P(CH2)4PPh2}], [WI2(CO)3(AsPh3)-{eta-1-Ph2P(CH2)4PPh2}] and unchanged Ph2P(CH2)4PPh2.