FT-Raman, FT-IR and NMR spectra, vibrational assignments and density functional studies of 1,3-bis(benzimidazol-2-yl)-2-thiapropane ligand and its Zn(II) halide complexes

Abstract

1,3-bis(benzimidazol-2-yl)-2-thiapropane (L) ligand and its zinc halide ZnX 2 (X = Cl, Br, I) complexes have been synthesized. The compounds were characterized using the elemental analysis, molar conductivity, FTRaman, FT-IR (mid i.r., far i.r.), 1 H and 13 C NMR spectra, and quantum chemical calculations performed with Gaussian 03 package program set. The optimized geometries and vibrational frequencies of the ligand and [Zn(L)Cl 2 ] complex were calculated using the DFT/ B3LYP method with a 6-31g(d) basis set. The geometry optimization of [Zn(L)Cl 2 ] yields a slightly distorted tetrahedral environment around Zn ion, while the molecule clearly reveals the Cs symmetry. The molar conductivity data reveals that the complexes are neutral. The ligand is bidentate, via two of the imine nitrogen atoms in the bisimidazole ring units, and together with the monodentate coordination of the two halides to the metal centre.

Palladium(II) and platinum(II) complexes containing benzimidazole ligands: Molecular structures, vibrational frequencies and cytotoxicity

“…The RMS error of the frequencies between the un-scaled and experimentally observed in case of benzimidazole L 2 for example was found to be 73 cm À1 . After scaling, the RMS error are found to be 8 and 25 cm À1 for 6-31G(d) and LANL2DZ basis sets, respectively, suggesting that the 6-31G(d) basis set gives more accurate results which is in agreement with the previously reported work [28,29].…”

“…The band at 1680 cm À1 is assigned to t(C@N) and is in a good agreement with the un-scaled calculated mode, 1687 cm À1 . It is possible to notice that in the latter range, the scaling is not necessary, as already pointed by Agathabay et al [28] and Miranda et al [29]. However, in benzimidazole L 2 , this band was overlapped with the aromatic C@C bands in the same region under the effect of the intermolecular hydrogen bond.…”

Comparative Study on the Catalytic Hydration of Carbon Dioxide by Catalysts that Mimic Carbonic Anhydrase Prepared with Zinc Salts

“…These peaks were also observed if ZnCl 2 was used and were assigned to the histidineÀZnÀCl complexes that were created through the binding of the Cl ion to Zn because of the in-terruption to the ZnÀOH coordination. [20,22] The appearance of the ZnÀCl coordination confirmed the inhibition by the Znbinding counter anion, which is in good agreement with previous catalytic performance data and dissociation enthalpy analysis.…”

Carbonic Anhydrase‐Mimetic Bolaamphiphile Self‐Assembly for CO2 Hydration and Sequestration

“…When the concentration of the ZnCl 2 solution in water was increased to 1 m M , two additional broad peaks appeared at 282 and 301 cm −1 , which correspond to the imidazole‐Zn‐Cl complex 13a. 14 The appearance of the imidazole‐Zn‐Cl complex implies that the excess Cl − ions interfere with the ZnOH ligation by generating ZnCl ligation. From these results, it can be inferred that a concentration of ZnCl 2 that is too high may interfere with ZnOH ligation, thus leading to decreased catalytic activity.…”