Conformational control of propeller-like chirality in Zn(II) complexes: Tightly balanced steric bias

The conformational behavior of a series of chiral tripodal ligand-Zn(II) co mplexes was examined. The ligands adopt propeller-like conformations upon c omplexation of trigonal bipyramidal metal ions such as Zn(II) with the chir ality of the propeller determined by the absolute configuration of a single chiral center in one of the tripod arms. Surprisingly, increasing the size of the substituent in the chiral arm did not improve the geometrical defin ition of the complexes, as indicated by the circular dichroism spectra of t he complexes. (C) 1999 Elsevier Science Ltd. Atl rights reserved.