Tripodal triphos {MeC(CH2PPh2)3} complexes of molybdenum(II) and tungsten(II). Reactions of [MI2(CO)3{MeC(CH2PPh2)3P,P′}] (M=Mo or W) with molybdenum(II) and tungsten(II) complexes

Equimolar quantities of [MI2(CO)3(NCMe)2] (M=Mo or W) and tripodal triphos {MeC(CH2PPh2)3} react in CH2Cl2 at room temperature for 5 min to give [MI2(CO)3{MeC(CH2PPh2)3P,P′}] (1 and 2) which contain one uncomplexed phosphorus donor atom capable of further coordination. Complexes 1 and 2 react in refluxing CHCl3 for 15 h (M=Mo) or 72 h (M=W) to give the complexes [MI2(CO)2{MeC(CH2PPh2)3P,P′,P″}] (3 and 4). The complexes [MI2(CO)3(NCMe)2] (M=Mo or W) react with two equivalents of 1 (LMo) and 2 (LW) to yield the trimetallic complexes [MI2(CO)3(LMo or LW)2] (5–8). A series of mixed-ligand seven-coordinate bimetallic complexes of the type [MI2(CO)3L(LMo or LW)] {M=Mo or W; L=PPh3, AsPh3, SbPh3; for M=W, P(OR)3 (R=Me, Et, Ph)} (9–17) have been prepared by reaction of [MI2(CO)3(NCMe)2] with one equivalent of L to give [MI2(CO)3(NCMe)L], followed by an in situ reaction with LMo or LW. Similarly, reactions of [MI2(CO)3{Ph2P(CH2)nPPh2}] {n=1 or 2} (prepared in situ) with equimolar amounts of LMo or LW affords the cationic complexes, [MI(CO)3(LMo or LW){Ph2P(CH2)nPPh2}]I (18–21). Reaction of equimolar quantities of [MI2(CO)(NCMe)(η2-EtC2Et)2] and LMo (for M=Mo) or LW (for M=W) affords the acetonitrile displaced products, [MI2(CO)(LMo or LW)(η2-EtC2Et)2] (22) and (23). Treatment of [MI2(CO)(NCMe)(η2-EtC2Et)2] with two equivalents of LMo (for M=Mo) or LW (for M=W) gives the mono(3-hexyne) trimetallic complexes [MI2(CO)(LMo or LW)2(η2-EtC2Et)] (24) and (25). All the new complexes described in this paper have been characterised by elemental analysis, IR, 1H- and 31P-NMR spectroscopy.