Inversion of the tetrahedral configuration of Zn(II), Cd(II), Hg(II), and Pb(II) 1,3-disubstituted 4-formy1-5-hydroxy-, 4-formy1-5-thio-, and 4-formy1-5-selenopyrazole bischelates

This paper presents results on the effects of the fusion of a pyrazole ring containing prochiral isopropyl and benzyl groups at N1 and c3 to the MN2X2 metallocycle, variation in the nture of the central metal atom, of the donor atom X (O, S, or Se), and of the substituents R1, R2, and R3 on the spectral characteristics and kinetic and activation parameters for enantiomerizaiton in the Zn(II), Cd(II), Hg(II), and Pb(II) bischelates (III) prepared using imines of 1,3-disubstituted 4-formy1-5-hydroxy-, 4-formy1-5-tthio-, and 4-formy1-5-selenopyrazoles