SYNTHESIS OF HETEROMETALLIC SPECIES WITH (PH2P)3CH OR (PH2P)3C- - CRYSTAL-STRUCTURES OF [MO(CO)4((PPH2)2- CHPPH2AUCL)],[MO(CO)4((PPH2)2CHPPH2AU(C6F5))] AND [NBU4][MO(CO)4((PPH2)2CPPH2AU(C6F5))

Treatment of [M(CO)4{(PPh2)2CHPPh2}] (M = Cr a, Mo b or W c) with 1 equivalent of [AuX(tht)] or [Au(tht)(PPh3)]ClO4 (tht = tetrahydrothiophene) afforded the neutral binuclear complexes [M(CO)4{(PPh2)2CHPPhAuX}] (X = Cl la-lc or C6F5 2a-2c), or the cationic derivatives [M(CO)4{(PPh2)2CHPPh2Au(PPh3)}]ClO4 3a-3c. Complexes 2 and 3 are readily deprotonated by [NBu4] (acac] (acac = acetylacetonate) to give the tris(diphenylphosphino)methanide species [MBu4]-[M(CO)4{(PPh2)2CPPh2Au(C6F5)}] 4a-4c and [M(CO)4{(PPh2)2CPPh2Au(PPh3)}] (5a-5c). Trinuclear compounds of the type [NBu4][{M(CO)4[(PPh2)2CPPh2]}2Au] 6a-6c were obtained by reaction of [M(CO)4{(PPh2)2CHPPh2}] with [NBu4][Au(acac)2] in the ratio 2:1. Single-crystal structure determinations were performed for compounds lb, 2b and 4b. In the neutral complexes lb and 2b the atoms C(2) (carbonyl), Mo, P(1) (co-ordinated to Au) and Au are essentially coplanar; the principal structural differences between the neutral and anionic (4b) complexes are the shorter P-C bonds and a rotation about the C-P(l) bond in the latter complex.