CHIRAL COMPLEXATION OF MULTIDENTATE N-HETEROCYCLIC PODAND LIGANDS BEARING HISTIDYL MOIETIES

摘要

Preorganized left-and right-handed helical conformations of the chiral pentadentate N-heterocyclic ligands bearing the podand histidyl moieties,N,N'-bis{(S)-(+)-1-methoxycarbonyl-2-(4-imidazoyl)ethyl}-2,6-pyridinedicarbox-amide(L-BHisPA)and the D-isomer(D-BHisPA),induce the chiral complexation through spiral coordination of the pentadentate BHisPA to Cu(II)center to give L-and D-BHisPA-Cu(II)as a A and A enantiomorph,respectively.Each complex is connected by continuous intermolecular hydrogen bonds in a solid state to form a hydrogen-bonded macrocycle with left-or right-handed windmill-like arrangement,respectively.In the case of the Cu(II)complex(L-HisPA-Cu(II))with the ligand bearing one histidyl pendant group,{(S)-(+)-1-methoxycarbonyl-2-(4-imidazoyl)ethyl}-2-pyridinecarboxamide(L-HisPA),each molecule is assembled in a solid state by continuous intermolecular hydrogen bonds and pi-pi interaction.