Phosphine complexes chelating

Zero-valent nickel-chelating phosphine complexes are used at 120°C under C02 pressure. 

Nucleophihc attack of methoxide ion on olefinic and acetylenic groups of suitable unsaturated phosphine complexes of platinum(II) takes place to give cyclic, a-bonded complexes. This reaction appears to occur whether or not the unsaturated group is coordinated to the metal (22). But-3-enyl diphenylphosphine forms a chelate complex with platinum(II) chloride which on treatment with sodium hydrogen car-... 

The behaviour of the phosphine complex PtBr2(ap)2 towards bromination is in marked contrast to that of PtBr2(oA)2 (the related arsine complex). Whilst the arsine complex gives platinum(IV) species on reaction with one equivalent of bromine, the phosphine complex gives the chelate compound PtBr2 (ap), and, presumably, CH2=CH CH2 ... 

The copolymerisation of CO and strained olefins such as norbornene and norbor-nadiene is effectively catalysed by Pd complexes with both phosphines and chelating diphosphines [43-49]. As previously mentioned, many model studies aimed at elucidating the elementary steps of alkene/CO copolymerisation have made use of cyclic alkenes in aprotic media because the products resulting from the insertion of... 

Dienes such as norbomadiene, 1,5-cyclooctadiene and Dewar hexamethylbenzene will form mononuclear chelate complexes such as PtX2(diene) (X = halogen).645 Alkene isomerization may occur. Thus whereas complexes of 1,4- and 1,5-cyclooctadiene have been obtained which involve no isomerization,646,647 under different experimental conditions phosphine complexes of... 

A platinum(H) complex has been prepared with a phosphine ligand chelated with a silyl. The complex (141) is formed by treating Pt(cod)2 with Ph2PCH2CH2SiHR R" (equation 423).1412 When R = R", racemic and meso diasteromers are formed in varying ratios consistent with asymmetric induction during stepwise chelation. The complexes can be used for asymmetric hydrosilylation.1413... 

Hydrides of Ni(I) and Ni(II) are known (37). A Ni(II) hydride appears to be an intermediate in the catalysis of olefin isomerization by phosphine complexes of nickel (61). Dilworth (62) has pointed out that stable hydride species are not obtained in model complexes with sulfur ligands. However, they may be possible within the confines of a protein chelate. 

This complex has four strong, sharp IR bands arising from the bound C02 at 1650, 1280, 1215 and 745 cm-1. A second structurally characterized example of this enhancement of the electrophilic C02 character is provided by the iridium bis(chelating phosphine) complex (P2)2IrC02Me, which shows similar features to the cobalt complex above. There are many other systems for which this mode of coordination is proposed and an extended discussion of these is available.149... 

The complexes ci -[PtCl(SnCl3)P2] may be obtained starting from either a cis-bis-phosphine complex of a tertiary aryl phosphine or a chelating diphosphine, e.g. PPh3 or DIOP complexes (20), (although careful examination of the P-31 spectra of the monodentate systems suggests that the trans isomer is also present). 

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