Phosphine complexes with

A number of tertiary phosphine complexes with bulky ligands (Figure 3.80) have modified square pyramidal structures, examples being M(I)3Br2, Pt(II)3Br2 and Pd(III)3Br2 (all X-ray) [136]. 

A series of phosphine complexes with cw-PtP2Cl2 geometries have been compared (Table 3.17). 

The soft Au+ forms relatively few complexes compared with those of phosphines. Complexes with ammines, nitriles and diazoles like Au(NH3)2 and Au(RCN)2 are known but little studied. In linear Au(NH3)2, Au-N is 2.01-2.03 A [70a], [Au(NCPh)2]+ has been used as a labile source of other gold complexes [70b]. AuCl(piperidine) is a monomer with weak tetra-meric association in contrast AuX(py) (X = Cl, Br, I) are [Aupy2]+[AuX2] with a chain structure in the solid state (and Au-Au interactions), suggesting a close balance between factors for molecular and ionic structures [70c] (note also the tetrahydrothiophene complexes in section 4.10.6). 

The chemistry of platinum(0) is overwhelmingly dominated by phosphine complexes with the general formula [Pt(PR3) ] (n = 2-4). These complexes undergo various types of oxidative addition reactions, activating a wide variety of bonds. The stability of the complexes depends on the steric... 

Table 2 Catalysts performance for different palladium phosphine complexes with lead based co-catalyst (0.25 mM Pd, 50 eg. PbO, 400 eg. TEAB). ...

Some other phosphine complexes with late transition metals such as Rh, Ir, Ni, Cu, and Co have been reported to act as active electrocatalysts for reduction of C02 into CO and/or 11 COO in anhydrous conditions.179-182... 

Ellis, J.W., Harrison, K.N., Hoye, P.A.T., Orpen, A.G., Pringle, P.G., and Smith, M.B., Water-soluble tris(hydroxymethyl)phosphine complexes with nickel, palladium, and platinum. Crystal structure of Pd P(CH2OH)3 4].cntdot.CH3, Inorg. Chem., 31, 3026, 1992. 

In contrast to the Pt(0) and Pt(II) complexes and the corresponding Rh(I) and Rh(III) complexes, the iridium complexes have rarely been employed as hydrosilylation catalysts [1-4]. Iridium-phosphine complexes with d metal configura-tion-forexample, [Ir(CO)Cl(PPh3)2] (Vaska s complex) and [Ir(CO)H(PPh3)3]-were first tested some 40 years ago in the hydrosilylation of olefins. Although they underwent oxidative addition with hydrosilanes (simultaneously to Rh(I) com-... 

A large number of nickel(O) phosphine complexes with rj2-bonded unsaturated organic molecules have been reported. Here we will review relevant examples of complexes with f 2-bonded molecules which contain a number of Ni—C bonds not exceeding the number of bonds from nickel to non-carbon atoms (usually phosphorus). The early examples (up to 1972) of complexes with alkenes have been extensively reviewed.11... 

Fluorophosphinenickel(O) complexes can be formed by reaction of the corresponding chloro-phosphine complexes with potassium fluorosulfinate (equations 9 and 10).1718 The metal inhibits oxidation of the ligand to the phosphinic fluoride, a reaction that occurs readily to the free ligand. 

T7fficient catalytic asymmetric hydrogenations have been achieved using an optically active phosphine complexed with rhodium (I, 2,3, 4, 5, 6, 7, 8). Through this process it is now possible to prepare a number of optically active a-amino acids from the corresponding unsaturated precursor without the usual resolution step by the following sequence. 

Coordinated CS2 groups can react via dimerization and abstraction of CS2, as can be seen in a survey of reactions of a rhodium(I) phosphine complex with CS2 (Scheme 1). The dimerization can be throught to proceed through a nucleophilic attack on the carbon atom of CS2 via an end-on intermediate of the heteroallene fragment.1011... 

Addition of arylboronic acids to a,/3-unsaturated ketones can be catalysed by palladium(0)-phosphine complexes with chloroform in the presence of a base. 

In a continuous set-up using Go-5, a considerable decrease in activity was also observed in comparison with the monomeric models. This effect was partly explained by deactivation of the catalyst due to the reaction of the catalytic units with the membrane or to some dendritic effect (due to the proximity of the unit centers leading to double or multiple phosphine complexation with the same palladium center), since the formation of a palladium black precipitate was observed on the membrane. Tests with the Go dendrimer model ligand (without palladium) showed a retention degree of 85%. This fact could also partly explain the decrease in activity due to the washout of catalyst during the reaction. However, a first-generation Gi-5 catalyst, with a higher retention, showed almost the same deactivation behavior. Thus, catalyst decomposition is most probably the main reason for the observed deactivation. 

Phosphine complexes with alkyl ligands are discussed in Section 17-D-9. 

Homoleptic phosphine complexes with transition metals, such as [Ni(PH3)4] or [Ni(PPh2H)4], have been prepared. " The main group Me3GaPH3 coordination compound can be pyrolyzed to afford GaP in Na+/H+ exchanged zeolite Y. ... 

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