Chiral 1D and 2D Assembly Structures of Self-Complementary Copper(II) Complexes with Imidazole-Containing Ligands

Abstract

1-D system: Copper(II) complex with pentadentate strand-type ligand involving two imidazole groups exhibits a self-complementary double-faced H-bonding recognition and enantioselective self-assembly behavior. The mono-deprotonated complex includes one imidazole and one imidazolate moiety, and due to the spiral arrangement of the acyclic ligand, induces C(clockwise) and A(anticlockwise) enantiomers. The complex functions as chiral building component and aggregates into …CCCC… and …AAAA… homochiral 1D zigzag-chains, owing to hydrogen-bonding between the imidazole and imidazolate groups of adjacent homochiral units. 2-D system: Copper(II) complex with a hexadentate tripod-type ligand involving three imidazole groups induces a chirality of C(clockwise) and A(anticlockwise) enantiomers due to the screw coordination arrangement of the tripod-type ligand around the metal ion. Further, the hemi-deprotonated species functions as a chiral self-complementary double-faced H-bonding recognition unit and form a two-dimensional extended honeycomb structure due to the intermolecular imidazole-imidazolate hydrogen bondings. The generated honeycomb structure is a chiral layer constructed by homochiral aggregation.