Zinc(II) and mercury(II) coordination architectures with two pyridyl/benzimidazol-1-yl-based ligands: Crystal structures and photoluminescent properties

摘要

In our efforts to investigate the relationships between the structures of ligands and their complexes, two structurally related ligands, 1-(2-pyridylmethyl)-1H-benzimidazole (L~1) and 1-(4-pyridylmethyl)-1H_benzimidazole (L~2), and their four complexes, [Zn(L~1)_2Cl_2] (1), [Hg(L~1)B_r2]. (2), {[Zn(L~2)C1_2](CH_3CN)}. (3) and [Hg(L~2)Br_2]_2(CH_3CN)_2 (4) were synthesized and structurally characterized by elemental analyses, IR spectra and single-crystal X-ray. diffraction analysis. Structural analyses show that 1 has a mononu_clear structure, and 2 and 3 both take 1D structure. While 4 takes a dinuclear structure. 1, 2 and 4 were further linked into higher-dimensional supramolecular networks by weak interactions, such as C-H...CI and C-H...Br H-bonding, C-H...π, and π...π stacking interactions. The structural differences of 1-4 may be attributed to the difference of the spatial positions of the terminal N donor atoms in the pendant pyr_idyl groups in L~1 and L~2, in which the pyridine rings may act as the directing group for coordination and the benzimidazole rings act as the directing group for π...π stacking and C-H...π interactions. The luminescent properties of the corresponding complexes and ligands have been further investigated.