Binuclear oxidative additions

Oxidative addition reactions have been observed also for the binuclear clusters of other d-transition elements with multiple M-M bonds [1,116,117]. The multiplicity of the M-M bonds must decrease in these reactions. It is known from organic chemistry that similar reactions are extremely characteristic of unsaturated organic compounds. We believe that the capacity for oxidative... 

Apart from reactions involving the oxidative addition of oxygen, the usual oxidation-reduction reactions have also been observed for binuclear technetium clusters with multiple M-M bonds (in this case they must be accompanied by a change in the multiplicity of the Tc-Tc bonds up to their complete dissociation)11 (15,16) [11,80],... 

Stepwise addition of halogens to the trimeric complex, [Au C(OMe)= NMe ]3 produced (155) three complexes Au3 C(OMe)=NMe 3X ] (n = 2,4,6) by consecutive oxidation of the three gold(I) centers. Binuclear gold(I) ylide complexes, however, underwent (56) consecutive oxidative addition of X2 to give formal gold(II) and finally gold(III) products [Eq. (49)]. Crystal structure (188) and spectroscopic (56. 189, 190) data have... 

Attempts have been made to mimic proposed steps in catalysis at a platinum metal surface using well-characterized binuclear platinum complexes. A series of such complexes, stabilized by bridging bis(diphenyl-phosphino)methane ligands, has been prepared and structurally characterized. Included are diplati-num(I) complexes with Pt-Pt bonds, complexes with bridging hydride, carbonyl or methylene groups, and binuclear methylplatinum complexes. Reactions of these complexes have been studied and new binuclear oxidative addition and reductive elimination reactions, and a new catalyst for the water gas shift reaction have been discovered. 

Binuclear reductive eliminations followed by oxidative addition may also be involved in reactions such as Equation 8. 

In general, oxidative addition reactions occur at mononuclear complexes as discussed above. Oxidative addition of dihydrogen often occurs at binuclear complexes. The reaction of dicobalt octacarbonyl may illustrate this ... 

The corresponding hydrido/alkyl (and aryl) complexes v-[RuHR(L-L), ] (L-L = dppe, dppm, dmpe R = Me, Et, Ph) are readily prepared from m-[RuClR(L-L)2] and Li[AlH4]1659 whereas treatment of cis- or tvans-[RuCl2 (dmpe)2 ] with arene radical anions affords d.v-[RuH(f 1-aryl)(dmpe)2] (aryl = phenyl, 2-naphthyl, anthryl, phenanthryl).1389 In solution, these compounds are in tautomeric equilibria with significant concentrations of Ru° complexes (e.g. equation 148) although X-ray analysis for aryl = 2-naphthyl confirms the presence of the six-coordinate Ru" species (373) in the solid state.2459 Some reactions of (373) with various substrates to produce other hydrido complexes are shown in Scheme 74.44>24m Note that the compound of empirical formula [ Ru(dmpe)2 ] obtained by pyrolysis of [RuH(2-np)(dmpe)2] (reaction (iv) Scheme 74) is a binuclear Ru" hydrido complex, resulting from intermolecular oxidative addition of methyl groups to ruthenium.1390... 

In 1982, novel diplatinum(II) diphosphite complexes were reported162. These compounds were readily generated by oxidative addition to the binuclear platinum(II) tet-rakis(diphosphite) complex, [Pt2(pop)4]4 (pop = P205H2 ), with halogens or methyl... 

In this case the proposed hydridodiplatinum(I) intermediates could not be isolated or detected, and it is likely that the subsequent intramolecular binuclear oxidative addition is very ast. 

Whereas IrCl(CO)(PPh3)3 has a very rich oxidative addition chemistry, the reaction of H2 with the analogous Rh compound does not give a stable product but leads to labilization of CO and formation of a binuclear complex. The reactivity of the Rh1 compounds decreases in the order X = I > Br > Cl.26... 

The interaction of silanes with metal complexes strongly resembles the behavior of H2, i.e., both rf-silane complexes (21-XIII) and oxidative addition products (21-XIV) are observed. In binuclear complexes, silyl bridges of type (21-XV) may be found. 

The use of alkyl or aryl groups with coordinating heteroatoms such as Ni or S can give mono- or binuclear chelated alkyls, which have greater stability and better control over stereochemistry e.g., a stereochemical experiment involving oxidative addition to Pt(0), which supports the SNj mechanisms, utilizes optically active d-(a-bromo-ethyOquinoline . A stable, optically active oxidative-addition product is formed with inversion of configuration ... 

It has been postulated that the formation of a /r-Tj iTj -vinyl ligand in binuclear intermediates involves the activation of a coordinated olefin by one metal center followed by an intramolecular oxidative addition of a... 

Oxidative additions both to bridged, binuclear complexes lacking metal-metal bonds and to mononuclear complexes with sterically small ligands can result in metal-metal bonds. 

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