Stereoselectivity in Reactions of Metal Complexes

Article abstract of DOI:10.1002/hlca.19920750430

The stereoselective formation of the 1:2 complexes and (M = Ni²⁺, Cu²⁺, PhEt-sal = N-(1-phenylethyl)salicylaldimine) has been determined by circular dichroism (CD) measurements.Stereoselectivity, defined as S = K_meso/2K_rac, has been found to be 2.48 for , corresponding to a 21percent excess of the mixed species relative to the statistical amount.This value is temperature-independent between 15 and 35 deg C.Whereas the absence of stereoselectivity in the formation of is confirmed, weak stereoselectivity is observed for (2percent excess of the mixed species).The CD intensity of the latter complex strongly depends on temperature and decreases by 12percent, when the temperature is increased from 15 to 35 deg C.Small but significant stereoselectivity is found for the formation of the Schiff-base complexes and in acetone with 1.0percent and 2.4percent excess, respectively, of the mixed species over the statistical value.