Transition metals solvent exchange reactions

Labile species are usually main group metal ions with the exception of Cr2+ and Cu2+, whose lability can be ascribed to Jahn-Teller effects. Transition metals of classes II and III are species with small ligand field stabilization energies, whereas the inert species have high ligand field stabilization energies (LFSE). Examples include Cr3+ (3d3) and Co3+ (3d6). Jahn-Teller effects and LFSE are discussed in Section 1.6. Table 1.9 reports rate constant values for some aqueous solvent exchange reactions.8... 

Square-planar stereochemistry is mostly confined to the d8 transition metal ions. The most investigated solvent exchange reactions are those on Pd2+ and Pt2+ metal centers and the mechanistic picture is well established (Table XIV (194-203)). The vast majority of solvent exchange reactions on square-planar complexes undergo an a-activated mechanism. This is most probably a consequence of the coordinatively unsaturated four-coordinate 16 outer-shell electron complex achieving noble gas... 

The interpretation of the activation volume for solvent exchange reactions on metal ions is based on the transition state theory (19). The experimentally... 

Within solution inorganic chemistry, there would be no apparent reason to obtain NMR spectra at high pressures in structural characterization studies. It prevails that most applications of hp NMR spectroscopy relate to solvent exchange reactions on solvated metal ions their mechanisms often have direct bearing upon the kinetics and mechanisms of substitution of one or more solvent molecules from a metal center by other ligands. The first part of the results section provides ample illustration of the value of high-pressure measurements on transition metal and lanthanide ions, fully... 

Recently, Connick et al. (16a, b) have studied exchange reactions of water between the coordination sphere of transition metals and the solvent by O17 shifts. 

Examinations of possible correlations between the volume of activation and the entropy of activation for series of similar reactions have been reported for reactions of transition metal coordination compounds, such as solvent exchange, ligand substitution, or isomerization.163 167 A limiting factor in a potential correlation may be the lack of precision that often attends experimental determination of the entropy of activation. Attention has been drawn specifically to the qualitative nature of the correlations between the two parameters for solvent exchange at some 3 + cations, and at square planar Pd2+ and Pt2+ ions.168... 

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