Ligand diphenylphosphinous acid

Platinum(II)15 and palladium(II)16 complexes of phosphorus trichloride undergo solvolysis in water and alcohols to form complexes with orthophosphorous acid or orthophosphite ligands (equation 6). Similar reactions occur between the palladium(II) phenyldichlorophosphine complex (8) and the diols ethyleneglycol and catechol, but new chelate rings are not formed (Scheme 2). Solvolysis also occurs with attack of diphenylphosphinic acid or a similar diphenylchlorophosphine complex (9) (equation 7). The palladium complexes (8) and (9) are unstable to excess methanol, water or base and undergo reduction. Similarly, the phosphorus trichloride gold(I) complex (10) is reduced by water, but forms stable products on reaction with alcohols (equation 8).15 During the above reactions, the phosphorus—metal bond remains intact and the overall process is one of substitution at phosphorus. 

The mixed anhydrides of diphenylphosphinous acid and heavily substituted alkenoic acids displace one PPh3 ligand from [RhCl(PPh3)3] to form a complex where the anhydride is coordinated through phosphorus. If these products are treated with thaUium(I) or silver(I) salts, the anhydride coordinates additionally through the carbonyl oxygen and the chloro ligand is displaced. 

A few derivatives are known in which the Group VI metal has been oxidized by an oxygen-containing ligand. Treatment of hexacarbonyl-molybdenum with sulfur trioxide in liquid sulfur dioxide forms pyro-sulfato(tetracarbonyl)molybdenum, Mo[0(S03)2](CO)4, as an air-stable, hygroscopic molybdenum(II) compound, which may be polymeric 141). Treatment of hexacarbonylchromium with diphenylphosphinic acid yields a number of species of varying molecular weight, formulated as (III) 142). 

The previous extension of solvent mixtures involved solvent interfaces. This organic-water interfacial technique has been successfully extended to the synthesis of phenylacetic and phenylenediacetic acids based on the use of surface-active palla-dium-(4-dimethylaminophenyl)diphenylphosphine complex in conjunction with dode-cyl sodium sulfate to effect the carbonylation of benzyl chloride and dichloro-p-xylene in a toluene-aqueous sodium hydroxide mixture. The product yields at 60°C and 1 atm are essentially quantitative based on the substrate conversions, although carbon monoxide also undergoes a slow hydrolysis reaction along with the carbonylation reactions. The side reaction produces formic acid and is catalyzed by aqueous base but not by palladium. The phosphine ligand is stable to the carbonylation reactions and the palladium can be recovered quantitatively as a compact emulsion between the organic and aqueous phases after the reaction, but the catalytic activity of the recovered palladium is about a third of its initial activity due to product inhibition (Zhong et al., 1996). 

A more versatile behavior was observed with dianionic H(T 6H ligands (Table 9) diols act as bidentates,186,187 while cv-hydroxycarboxylic acids behave as monodentate monoanionic ligands, e.g. in cinnamates,188 or as bidentate dianionic ligands189,190 in alkoxycarboxylates. In the case of catechol, ionic species were shown to exist in solution for both metals, but were isolated for tantalum only.191 The bidentate monoanionic diphenylphosphinate ligand can replace from one to three alkoxo groups in Ta(OMe)5 to yield low molecular weight polymers (Table 9).192... 

Compounds.- A third part of a review of P-H addition to unsaturated systems has appeared, covering addition to unsaturated ligands in the coordination sphere of a metal.Addition of diphenylphosphine to the free vinyl group of the [4+2]cycloadduct of 3,4-dimethyl-l-phenylphosphole and phenyldivinylphosphine (both in the form of metal complexes) has led to the unsymmetrical triphosphine (40), isolated as the related metal complex.A similar u.v.-induced addition to methyl(vinyl)cyclotetrasiloxane has given a tetraphosphine which, on treatment with acid, forms an... 

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