Supramolecular assembly driven by hydrogen-bonding and pi-pi stacking interactions based on copper(II)-terpyridyl complexes

摘要

Six 2D and 3D supramolecular complexes [Cu(L1)(O2CCH3)(2)] center dot H2O (1), [Cu-2(L-2)(2)(mu(2)-O2CCH3)(2)](BF4)(2) (2), [Cu-2(L1)(2)(BDC) (NO3)(2)] center dot 0.5H(2)O (3) [Cu-2(L2)(2)(BDC)(NO3)(2)] (4), [Cu-2(L3)(2)(BDC)(NO3)(2)]. 0.514,0 (5) and [Cu-2(L2)(2)(BDC)(H2O)(2)](BDC) center dot 8H(2)O (6) (L1 = 4'-(4-pyridyl)-2,2':6',2"-terpyridine, L2 = 4'-(2-pyridyl)-2,2':6',2"-terpyridine, L3 = 4'-phenyl-2,2':6',2"-terpyridine, BDC = 1,4-benzenedicarboxylate), have been prepared and structurally characterized by X-ray diffraction crystallography. In complexes 1, 3, and 4, 1D channels are formed through C-H center dot center dot center dot O and C-H center dot center dot center dot N hydrogen-bonding interactions, and further linked into 3D structure via C-H center dot center dot center dot O and O-H center dot center dot center dot O interactions. Complex 2 is a 2D layer constructed from intermolecular C-H center dot center dot center dot F and pi-pi stacking interactions. In the structure of 6, the BDC2- ions and solvent water molecules form a novel 2D layer containing left- and right-handed helical chains via hydrogen-bonds, and an unusual discrete water octamer is formed within the layer. In 2, 4, 6 and [Ag-2(L2)(2)](PF6)(2) (7) the bonding types of pendent pyridines of L2 depending on the twist about central pyridines are involved in intramolecular (2 and 4), intermolecular (6) or coordination bonds (7) in-twist-order of 5.8, 3.7, 28.2 and 38.0, respectively. Differently, the pendent pyridines of L1 in 1 and 3 form intermolecular hydrogen bonds despite of distinct corresponding twist angles of 25.1 degrees (1) and 42.6 (3). Meanwhile, pi-pi stacking interactions are present in 1-6 and responsible for the stabilization of these complexes. (c) 2006 Elsevier B.V. All rights reserved.