Supramolecular assembly of two two-folded helical structures based on 2-substituted 8-hydroxyquinoline complexes

Based on two 2-substituted 8-hydroxyquinoline ligands containing -NO2 and -Cl, two complexes [Co(L-2)(2)(pyridine)(2)] (1) and [Cu(L-3)(2)] (2) were synthesized and characterized with single-crystal X-ray diffractions, powder X-ray diffractions (PXRD), thermal analyses (TGA) and elemental analyses (EA). In the solid state, the supramolecular structures of 1 and 2 feature two different two-folded helical chains, which were constructed by non-covalent interactions, such as pi-pi stacking, C-H...pi and C-H center dot center dot center dot O, C-Cl...pi and Cl center dot center dot center dot Cl interactions. The present research holds great promise in the development of novel functional helical structure, and may contribute to the understanding of helical organized systems in biology. (c) 2013 Elsevier B.V. All rights reserved.