Polyhydride

Perhaps the most exciting recent development in the chemistry of hydrogen is the discovery that, in transition metal polyhydrides, the molecule Hj can act as a dihapto ligand, (see below). 

There is even a rare example involving a d polyhydride ... 

Bayse, C.A. and Hall, M.B. (1999) Prediction of the Geometries of Simple Transition Metal Polyhydride Complexes hy Symmetry Analysis. Journal of the American Chemical Society, 121, 1348-1358. 

A series of Irv boryl polyhydrides, cp IrH2XBR2 (X = H and BR2 = Bpin (1) (pin = 02C2Me4), Beat (2) (cat = 02C6H4), B02C6H2-3,4-Me2 (3) Bey (4), X = Bpin and BR2 = Bpin (5)) have been prepared and isolated by Hartwig and Kawamura according to Reaction Scheme 1. The X-ray crystal characterization of (1) is reported. (1) to (5) react regiospecifically with alkanes to produce free functionalized products. 

Polynuclear complexes associated with transition metal polyhydrides and silver cations have been described those which present silver—metal bonds are more numerous and they will be... 

Path C (Scheme 17.5), which involves reductive elimination of formic acid before reaction with H2, is only possible for dihydride and polyhydride catalysts. This pathway was proposed for the catalyst precursor [Rh(nbd)(PMe2Ph)3]+ by Tsai and Nicholas [19], who observed the intermediates [RhH2(PMe2Ph)3L]+ and [RhH( /2-02CH)(PMe2Ph)2L]+ (L=HzO or solvent). 

Generation of Reactive Intermediates via Photolysis of Transition-Metal Polyhydride Complexes... 

The photochemical properties of several transition metal polyhydride complexes are described. Irradiation of [MoH Cdppe) ] (dppe =... 

A number of studies have demonstrated that photolysis of transition metal di- and polyhydride complexes can lead to the generation of very reactive intermediates, generally via photo-induced loss of H9 Cl, 2). Two such examples are shown in eqs 1 (3) and 2 (4-8). Z... 

Photoinduced reductive elimination of from polyhydride complexes, HxMLn (x > 3) can, in principle, lead to the generation... 

Since photolysis of monomeric di- and polyhydride transition metal complexes often leads to elimination of H2 as the... 

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