Structural and spectral properties of a zinc(II) coordination polymer: A combined experimental and theoretical study

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2014-10, Vol.131, p.102-108
• Main Authors: Hao, Jin-Ming, Li, Guang-Yue, Li, Yue-Hua, Cui, Guang Hua
• Format: Article
• Language: English
• Subjects: Benzimidazole; Coordination polymer; Crystal structure; Fluorescence; TDDFT
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2014.04.005

[Display omitted] •A 2D ZnII coordination polymer have been synthesized and characterized.•X-ray single-crystal structure analyses and discussion for the polymer.•The polymer exhibit interesting fluorescent properties in solid state.•The fluorescent peaks are originated from π*–π and charge-transfer n–π transitions. A novel 1D zinc(II) coordination polymer [Zn(bbbm)Cl2]n (where bbbm=1,4-bis(N-benzimidazolyl)butane) was synthetized by ZnCl2 and bbbm ligand under hydrothermal conditions, and its structural and spectral properties were studied by both experimental and theoretical techniques. The center zinc(II) ion displays four-coordinated in a tetrahedral geometry by two chloride anions and two N atoms of distinct bbbm ligands. Adjacent chains are further connected into a 2D layer structure through π–π stacking interactions. Vibrational frequencies of [Zn(bbbm)Cl2]n have been calculated using DFT/B3LYP/TZVP method, and well reproduced IR data. Furthermore, the vertical excitation energies from time-dependent DFT calculation confirmed that the fluorescent peaks at 385nm and 450nm could respectively be assigned to the π→π* transition within the bbbm ligands and π→n transition from chloride anion to bbbm ligand.