Interconversion rate constant solvent effects

The optically active square pyramidal complexes 39 and 41—49a and b epimerize in solution, as shown in Fig. 4 for 38a and b, some of them at lower, and some at higher temperatures5 f 63-65. The first-order decline in optical rotation yields overall rate constants k, which are the sum of the individual rate constants k and fc2 f°r the interconversion of both epimers into each other56,63-65 [Eq. (19)]. These first-order rate constants k for the approach to equilibrium were used for the calculation of the half-lives given in Table 1. A change in the solvent from DMF to toluene has only a small effect on the half-lives of the configurational stability63. ... 

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