Oxidative addition dinuclear

Complex [(CXI )Ir(/j,-pz)(/i,-SBu )(/j,-Ph2PCH2PPh2)Ir(CO)] reacts with iodine to form 202 (X = I) as the typical iridium(II)-iridium(II) symmetrical species [90ICA(178)179]. The terminal iodide ligands can be readily displaced in reactions with silversalts. Thus, 202 (X = I), upon reaction with silver nitrate, produces 202 (X = ONO2). Complex [(OC)Ir(/i,-pz )(/z-SBu )(/i-Ph2PCH2PPh2)Ir(CO)] reacts with mercury dichloride to form 203, traditionally interpreted as the product of oxidative addition to one iridium atom and simultaneous Lewis acid-base interaction with the other. The rhodium /i-pyrazolato derivative is prepared in a similar way. Unexpectedly, the iridium /z-pyrazolato analog in similar conditions produces mercury(I) chloride and forms the dinuclear complex 204. 

An extensive chemistry is developing of dinuclear gold(III) complexes with phosphorus ylid ligands (Figure 4.41). As mentioned in section 4.19, gold(I) compounds can undergo one- or two-electron oxidative additions,... 

Gold in the oxidation state +1 also tends to form dinuclear complexes with bridging amidinate ligands. A typical example is Au2[HC(NC6H3Me2-2,6)2]2 (cf. Section Oxidative addition of iodomethane to the dinuclear gold(I)... 

A related dinuclear species 77, recently described, constitutes the first dinuclear gold(I) complex with heterobridged phosphor-1,1 -dithiolato moieties and bis(ylide) bridging ligands [ 102]. It is obtained by reaction between [ AuS2PPh2] and the diylide gold complex 74 (R=Me). No intermolecular Au-Au interaction is observed in 77 but the oxidative addition of chlorine to the product leads to a new complex 78 in which a single bond is formed between the two Au(II) centers (Scheme 26). 

Square-planar complexes Pt(CO)(PR3)Cl2 (R = Ph or Bu) are transformed to the dinuclear [R COPt(PR3)Cl]2 by the action of HgRj (R = Me or Ph) under mild conditions 82). These reactions are thought to proceed through the oxidative addition to Pt(II) of HgRj, migration of R onto CO, and elimination of R HgCl. 

Oxidative-Addition Reactions to the Dinuclear Gold(l) Amidinate Complex 9... 

Oxidative-addition reactions have been widely studied with bridged dinuclear metal complexes [1,2,5, 32]. Earlier work with the ylides and sulfur bonded ligands... 

Figure 1.13 Synthesis of gold(ll) amidinate complexes by oxidative-addition to the dinuclear gold(l) amidinate.

A in the dinuclear complex to 2.00-2.004 A in the oxidative-addition products. The Au atoms have a nearly square-planer coordination geometry. 

The reaction of the dinuclear gold(I) amidinate complex, [Au2(2,6-Me2Ph-form)2], with Hg(CN)2 (1 2 stoichiometry) in THF forms a 2D coordination polymer, [Au2(2,6-Me2Ph-form)2]-2Hg(CN)2 2THF, not the expected oxidative-addition product of the type formed vdth the ylides. White crystals and a yellow powder are formed. 

Fackler, J.P. (1997) Polyhedron report No. 63, metal-metal bond formation in the oxidative addition to dinuclear Gold(I) species. Implications from dinuclear and trinuclear gold chemistry for the oxidative addition process generally. Polyhedron,... 

Abdou, H.E., Mohamed, A.A. and Fackler, J.P. Jr (2004) Oxidative addition of methyl iodide to dinuclear Gold(I) amidinate complex schmidbaur s breakthrough reaction revisited with amidinates. ZeitschriJiJurNaturforschungB. A Journal of Chemical Sciences, 59, 1480-1482. 

Abdou, H. (2006) PhD. Thesis New Chemistry with Gold-Nitrogen Complexes Synthesis and Characterization of Tetra-, Tri-, and Dinuclear Gold(I) Amidinate Complexes. Oxidative-Addition to the Dinuclear Gold (I) Amidinate, A M University, Texas. 

Photochemical oxidative addition of (303) with I2 Mel or CH2I2 gives dinuclear Ir11 complexes (304).493 The crystal structure of (304), R = I, R = CH2I, is reported. 

Figure 27 Oxidative addition of the organochalcogen compounds to low-valent transition metal centers most often resulting in the cleavage of the chalcogen-chalcogen bond and the formation of mono- or dinuclear complexes with anionic bridging or terminal RE- (E = Se, Te) ligands.

A kinetic analysis of the styrene hydrogenation catalyzed by [Pt2(P205H2)4]4 [66] was indicative of the fact that the dinuclear core of the catalyst was maintained during hydrogenation. However, three speculative mechanisms were in agreement with the kinetic data, which mainly differ in the H2 activation step. This in fact can occur through the formation of two Pt-monohydrides, still connected by a Pt-Pt bond, or through the formation of two independent Pt-monohydrides. The third mechanism involves the dissociation of a phosphine from one Pt center, with subsequent oxidative addition of H2 to produce a Pt-dihy-dride intermediate. 

---