CARBONYLMETALATE-INDUCED PHOSPHORUS MIGRATION AND PH2PCH2PPH2-(DPPM-)ASSISTED SYNTHESIS OF BIMETALLIC COMPLEXES AND CLUSTERS OF PD AND PT WITH MO, W, MN, AND CO

The new triangular clusters [PtCo2(CO)7(mu-dppm)] (1), [PtMo2Cp2(CO)5( mu-dppm)] (2), and [PtW2Cp2(CO)5-(mu-dppm)] (3) were obtained from the reactions of[PtCl2(eta2-dppm)] with 2 equiv of the carbonyl metalates [CO(CO)4]-, [MO(CO)3CP]-, or [W(CO)3CP]-, respectively. In the case of [Mn(CO)5]- and depending on the stoichiometry used, the bimetallic [( eta2-dppm)PtCl{Mn(CO)5}] (4) or the trinuclear chain [(OC)5MnPt(CO)(mu -dppm)Mn(CO)4] (5) were obtained instead. Clusters 2 and 3 react rever sibly with CO to give respectively the chain complexes [CP(OC)3MoPt(CO )(mu-dppm)MO(CO)2CP] (6) and [Cp(OC)3WPt(CO)(mu-dppm)W(CO)2CP] (7), an alogous to 5. Cluster 1 undergoes CO substitution by dppm to give [PtC o2(CO)5(mu-dppm)2] (8) in which the Pt-Co bonds are bridged by dppm li gands. Dppm also reacts with clusters 2, 3, and 5 to afford the bimeta llic ionic complexes [(eta2-dppm)Pt(mu-dppm)MO(CO)2CP] [MO(CO)3CP] (9) , [(eta2-dppm)Pt(mu-dppm)W(CO)2CP][W(CO)3CP] (10), and [(eta2-dppm)Pt( mu-dppm)Mn(CO)4] [Mn(CO)5] (11). Alternatively, these complexes as wel l as the analogous [(eta2-dppm)Pt(mu-dppm)CO(CO)3][CO(CO)4] (12) may b e prepared from [Pt(eta2-dppm)2]Cl2 and the corresponding carbonylmeta lates. The reaction of [PdCl2(eta2-dppm)] with 2 equiv of the carbonyl metalate [CO(CO)4]- affords at -30-degrees-C the cluster [PdCo2(CO)7(m u-dppm)] which was not isolated but is analogous to 1. In solution, th is cluster undergoes a redox process leading to the known [Pd2Co2(CO)7 (mu-dppm)2] (13) or, alternatively, reacts with dppm to yield the stab le complex [PdCo2(CO)5(mu-dppm)2] (14), analogous to 8. The latter clu ster was also prepared from [Pd(eta2-dppm)2][BF4]2 and 2 equiv of [CO( CO)4]-. If chloride ions are added in the latter reaction, [ClPd(mu-dp pm)2Co(CO)2] (15) is formed instead. It reacts in toluene with [CO(CO) 4]- to give [(OC)4CoPd(mu-dppm)2Co-(CO)2] (16), which transforms slowl y in 14 by loss of CO and formal insertion of a CO(CO)3 moiety into a Co-P bond. On the basis of these results, the influence of the nature of the d8 metal (Pd or Pt), of the carbonylmetalates, and of the dppm stoichiometry on the structure of the products is discussed.