82307-38-8Relevant academic research and scientific papers
Synthesis and reactivity of Ph2PCH2PPh2- (dppm-) stabilized Pd-Co and Pd-Pt-Co clusters. Effect of platinum versus Palladium on the neighboring palladium center
Braunstein, Pierre,De Méric De Bellefon, Claude,Ries, Michel
, p. 1338 - 1346 (2008/10/08)
The quantitative and regioselective synthesis of the mixed-metal cluster [PdPtCo2(CO)7(dppm)2] (1b) was achieved by the reaction of the bimetallic complex [PdPtCl2(dppm)2] (dppm = μ-Ph2PCH2PPh2) with [Co(CO)4]-. As a result of phosphorus migration from palladium to cobalt, formal insertion of the Co(CO)3 fragment into a metal-phosphorus bond of the precursor exclusively occurs into the more labile P→Pd bond. The presence of numerous potential reaction centers (e.g., metal(s), metal-metal bonds, and CO and dppm ligands) in these clusters led to an investigation of the site selectivity toward attack by nucleophiles. The lability of the exocyclic Co(CO)4 fragment was evidenced and compared between 1b and [Pd2Co2(CO)7(dppm)2] (1a). Although a Pd-Co bond is involved, this lability is very sensitive to the neighboring metal center (Pd or Pt). Transmission of electronic effects from one metal center to another was evidenced, and a platinum effect was observed in dissociating solvents, where 1a is partly dissociated but 1b is completely dissociated into [PdPtCo(CO)3(S)(dppm)2][Co(CO)4] (S = solvent), This is a reversible process, as is the equilibrium between 1 and halide anions. Solvento clusters were prepared that possess a labile coordination site on Pd leading to completely regioselective reactions with donor molecules, e.g., phosphines, CO, or C2Ph2. These ligands are labile (PR3 2Ph2 a platinum effect on the reactive Pd center. The tris[bis(diphenylphosphino)methane] cationic cluster [Pd2Co(CO)2(dppm)3]+ was isolated, in which all the metal-metal bonds are bridged by dppm ligands. Spectroscopic IR and 1H, 31P{1H}, and, sometimes, 195Pt{1H} NMR data are discussed and confirm that in all these reactions the basic PdMCo(dppm)2 (M = Pd, Pt) framework is maintained, thus showing a certain robustness and that the reactions investigated all take place in the plane of this framework. The Co(CO)3P fragment in the triangulo clusters reported in this work behaves as a neutral 3-electron donor organometallic bridging group vs the Pd-Pd or Pt-Pd unit.
Synthesis and Reactions of the Heterobimetallic Complex
Pringle, Paul G.,Shaw, Bernard L.
, p. 889 - 896 (2007/10/02)
New methods of preparing (1b) (dppm = Ph2PCH2PPh2) are described, such as reduction of with zinc dust, formic acid, or hydrazine.Treatment of 3-allyl)2> with an excess of dppm gives pure (1b) readily, albeit in only 45 percent yield. 3-C3H5)ClPd(μ-dppm)PdCl(η3-C3H5)> is also described.The best route to (1b) is to treat and dppm with giving yields of 80-90 percent.Similar treatment of and dppm with t)2> gives (1a), often contaminated, however, with ca. 10 percent of .Treatment of dppm and with t)2> gives the previously unknown heterobimetallic complex (1c) in excellent yield (83-92 percent) and purity.The corresponding dibromide, di-iodide, and dithiocyanate were prepared from (1c) by metathesis.Complex (1c) readily reacts with some small molecules, SO2, CO, MeO2CCCCO2Me or CS2, to give 'A-frames' , , , and respectively.The addition of SO2, CO, or CS2 is reversible and SO2 promotes or catalyses the displacement of CO.Hydrogen-1, 31P-, and 195Pt n.m.r. data are given and discussed as are some i.r. data.
Mixed Palladium-Platinum Complexes with Ph2PCH2PPh2 (dppm)
Pringle, Paul G.,Shaw, Bernard L.
, p. 81 - 82 (2007/10/02)
The first mixed palladium-platinum complexes with dppm, together with their A-frame adducts with CO, SO2, and MeOOCC=-CCOOMe, are described.
