A Zinc(II) coordination complex containing multi-benzimidazole ligand： synthesis， characterization and theoretical research
ZHOU Hongbin1， LI Ji2， XIAO Fengping1， MENG Xianggao1
1.College of Chemistry， Central China Normal University， Wuhan 430079， China；2.School of Biological and Environmental Engineering， Guiyang University， Guiyang 550005， China
Abstract：One new multi-benzimidazole (bzim) zinc (II) coordination compound， [Zn(NTB)Cl]2·(ZnCl4)·4(CH3OH) (1) (NTB＝Tris(2-benzimidazolylmethyl)amine)， has been synthesized and characterized by infrared absorption spectroscopy， elemental analysis and X-ray diffraction. Compound (1) was crystallized in the triclinic P-1 space group with a＝1.3874(2) nm，b＝1.4095(1) nm，c＝1.6214(2) nm；α＝86.440(3)°，β＝87.296(2) °，γ＝70.699(3) °，V＝2.9855(6) nm3； μ＝1.520 mm－1，ρc＝1.504 mg·m－3，F(000)＝1384，R1＝0.0777， and wR2＝0.2068 for 9 770 observed reflections (I 〉 2σ(I)). Two [Zn(NTB)Cl]＋ cationic units， one (ZnCl4)2－ anionic unit and four methanol solvent molecules are existing in its asymmetric unit. The component ions are linked by N—H…O， N—H…Cl， O—H…Cl， C—H…π and π…π interactions into a complex three-dimensional network. A quantitative analysis of the intermolecular interactions in crystal (1) were analyzed by using Hirshfeld surface and fingerprint plot， indicating that the strong spikes are mainly ascribed to H…O and H…Cl interactions. The electronic structure was theoretically calculated at the DFT(RB3LYP)/6-31G＋(d， p) level for one discrete [Zn(NTB)Cl]＋ unit. Frontier molecular orbital analysis shows that the less delocalization between these BD orbits of CH2 group and BD* orbits of benzimidazole group may be facilitating for the formation of the Δ and Λ configurations for the NTB ligand. The mulliken charge analysis shows that the three nitrogen-bonded hydrogen atoms (H3/H5/H7) in the [Zn(NTB)Cl]＋ units possesses higher positive charges(about 0.28 a.u.) which can facilitate the formation of N—H…X interactions.
2021, Vol. 55 
