Platinum complexes hydrogen-deuterium exchange

The similarity between the hydrogen-deuterium exchange reaction of the aryldiimide- and arylhydrazine-platinum intermediates of this model and of N2ase is the best evidence for enzyme-bound diimide and hydrazine as intermediates (66). The correlation between the relative aflSnity of various ligands for N2ase and for some of the synthetic complexes of Fe, Co, Ni, Mo, Ru, Rh, Re, Os, and Ir that bind, but have not yet been shown to reduce, N2 (Table VIII) indicate that these metal complexes... 

A long controversy also grew up over the work of Shilov et al [28]. In 1969 these authors published the first example of homogeneous CH bond activation in alkanes the hydrogen—deuterium exchange reaction catalyzed by platinum(II) complexes (reaction 13). 

Hydrogen-deuterium exchange is catalysed by an unusually stable mercury-toluene complex that contains a GaMe3 moiety. The first homoleptic platinum complex with terminal and bridging Cp Ga ligands has also been made. This is the compound [Pt2(GaCp )2( i2-GaCp )3]. 

In the another hypothesis, it has been assumed [37] that the rotation of the alkyl group R in the coordination sphere of platinum entails an appreciable intensification of the nucleophilic properties of the carbon atom, which should facilitate the electrophilic attack on the latter by the deuterium cation D. The alkyl group rotates synchronously with the approach of D and the agostic coordination between the C-H bond and platinum ion is formed. Since it is evident that several hydrogen atoms can be substituted by deuterium in the alkyl group before it is split off from platinum, the proposed mechanism explains satisfactorily the multiplicity of different types of H-D exchange in the presence of platinum(ll) complexes. 

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