Ligand isotopic exchange reactions

A number of short reviews have appeared in addition to those already mentioned. They deal with the reactivity of dinuclem jM-peroxo-cobalt(in) chelates and rhodium cyanides, with metal and ligand isotopic exchange reactions of chelate complexes, and the applications of isotopes to kinetic studies of carbonate systems. A new book deals with the diverse applications of n.m.r. for kinetic studies in solution, including a chapter devoted to st -eochemically non-rigid metsd chelate complexes. In a further review the dynamics of intramolecular metal-centred rearrangement reactiom of fris-chelate complexes is described. ... 

The most fundamental approach to assessing lability of complexes is by determination of the rate of isotopic exchange reactions. In the technetium-complex systems, no study of the exchange reaction on the central metal ion has been reported, but several reports have been published on isotopic exchange by ligand substitution. 

The isotopic exchange reaction by ligand substitution can be expressed in general as... 

Deuterium labelling can, in principle, provide mechanistic information on hydro-formylation reactions, but complications may arise if scrambling of the D-label bet veen a metal hydride and D2 is fast. The isotopic exchange reaction shown in Eq. (9) was probed by rapid scan HP IR spectroscopy (1.3 scans s" ) where 21 is the bidentate pyrrolyl-based phosphorus amidite ligand illustrated [8]. 

The iodo analogue in this series of compounds, GR 190028a (pKi = 8.2), was shown to be equipotent in vitro with GR 175737 [20], This compound was labelled by an isotopic exchange reaction (scheme 6) and evaluated for its potential use as a SPECT ligand for the H3 receptor. 

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