Synthesis and spectroscopic properties of some new bi-, tri- and tetrametallic complexes of the type [M(CO)5L], [M(CO)4L2] and [M(CO)3L3] {M = Cr, Mo, W; L = [Ph(CH2)2PPh2-P, P′}(η2-RC2R′)] (R = R′ = Me, Ph; R = Me, R′ = Ph)}

Abstract

Reaction of L {L = [ Ph(CH 2 ) 2 PPh 2 - P, P′ }(η 2 -RC 2 R′)] (R = R′ = Me, Ph; R = Me, R′ = Ph)} with an equimolar quantity of [M(CO) 5 (NCMe)] (M = Cr, Mo, W) (prepared in situ) gives high yields of the bimetallic complexes [M(CO) 5 L] {L = [ Ph(CH 2 ) 2 PPh 2 - P, P′ )(η 2 -RC 2 R′)] (M = Cr, W, R = R′ = Me; M = Cr, Mo, R = Me, R′ = Ph; M = Mo, W; R = R′ = Ph)} ( 1 → 6 ). Treatment of cis -[M(CO) 4 (piperidine) 2 ] (M = Mo, W) with two equivalents of L (as above) in refluxing CH 2 Cl 2 affords the trimetallic complexes [M(CO) 4 L 2 ] {L = [ Ph(CH 2 ) 2 PPh 2 - PP′ }(η 2 -RC 2 R′)] (M = Mo, W, R = R′ = Me; M = W, R = Me, R′ = Ph)} ( 7 → 9 ). The cis—trans isomerism of complexes 7 and 8 has been investigated by infrared spectroscopy. Reaction of fac -[Mo(CO) 3 (NCMe) 3 ] (prepared in situ) with three equivalents of L in refluxing acetonitrile yields the tetrametallic complexes [Mo(CO) 3 L 3 ] {L = [ Ph(CH 2 ) 2 PPh 2 - P, P′ }(η 2 -RC 2 R′)] (R = R′ = Me, Ph; R = Me, R′ = Ph)} ( 10 → 12 ). All the new complexes have been characterised by elemental analysis (C, H and N), infrared, 1 H NMR spectroscopy and in selected cases by 31 P NMR spectroscopy.