The C-H center dot center dot center dot Cl2Cu(II) synthon in the structural direction and assembly of supramolecular complexes with the 3,3 '-bis(2-benzimidazolyl)-2,2 '-dipyridine ligand and its N-substituted derivatives

摘要

Three new Cu(II) supramolecular complexes [Cu(L-1)Cl-2]center dot 2DMF (1), [Cu(L-2)Cl-2] (2) and [Cu(L-3)Cl-2]center dot DMF (3) (L-1 = 3,3'-bis(2-benzimidazolyl)-2,2'-dipyridine, L-2 = 3,3'-bis(N-ethyl-2-benzimidazolyl)-2,2'-dipyridine and L-3 = 3,3'-bis(N-benzyl-2-benzimidazolyl)-2,2'-dipyridine) have been prepared and characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. X-ray structural analysis of L-1,L-2 center dot 3.5H(2)O and L-3 center dot H2O indicates that all three ligands adopt the trans conformation with the two benzimidazole fragments located on opposite sides of the dipyridyl backbone. While in complexes 1-3, all the ligands display the cis conformation and behave as bidentate chelating reagents to coordinate with Cu(II). The inorganic chloride ions always act as a reliable hydrogen bonded acceptor in these structures, and the resulting C-H center dot center dot center dot Cl2Cu supramolecular synthons play a significant role in the formation and stabilization of the structures. Moreover, additional non-covalent interactions, such as C-H center dot center dot center dot pi, are also identified to extend the discrete (0-D) or low-dimensional (1-D) motifs into high-dimensional architectures.