Aquation rate constants metal-assisted reactions

Aquation rate constants [Co(NH,), X]", 34 165-166 ion pairing effects, 34 173 metal-assisted reactions, 34 168-169 pentaamminecobalt(III) complexes, 34 149 pentaamminemetal(III) complexes, 34 152-153... 

Spectacular increases in spontaneous and base-catalyzed or metal-assisted aquation rate constants of particularly pentaammineco-balt(III) complexes have been observed in the presence of polyelectrolytes and micelles. Polyelectrolytes are known to cause marked acceleration of reactions, though decelerations can be observed, and the effects are very large compared with those produced by equivalent amounts of corresponding low molecular weight substances similar effects are observed in solutions containing charged micelles. This area of research has been extensively reviewed (63,101,133,139,195, 206, 207), so discussion will be selective. 

Rate axd Equilibrium Constants for Metal-Assisted Aquation Reactions " ... 

More closely related to kinetics and mechanism are three reviews from Danish chemists, one on the state of the art with respect to Cr(III) substitution reactions and the other two ° survey /t-diol dinuclear Cr(III) systems. Chromium chemistry is also discussed in a general review on metal-ion-assisted aquation reactions " and in a review on the effect of pressure on reaction rates. In the following sections, units for and AH are in kJ mol A5 in J K mol A V in cm mol visible absorption spectral maxima (A ax) in nm, and molar extinction coefficients (e) in cm Unless otherwise stated, all rate constants are reported at 25.0 (298.2 K). 

---