Sharma Bharat Prasad, Adhikari Subin Jhashanath, Marasini Bishnu Prasad, Adhikari Rameshwar, Pandey Sarvesh Kumar, Sharma Motee Lal
Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu 44618, Nepal.
Bioinformatics and Cheminformatics Division, Scientific Research and Training Nepal P. Ltd., Bhaktapur 44800, Nepal.
Heliyon. 2023 Apr 5;9(4):e15239. doi: 10.1016/j.heliyon.2023.e15239. eCollection 2023 Apr.
The synthesis and characterization of two new Schiff base ligands containing 1,2,4-triazole moieties and their oxovanadium(IV) complexes have been reported. The ligands and their complexes were studied by ultraviolet-visible (UV-Vis), Fourier transform infrared (FTIR), proton nuclear magnetic resonance (H NMR), electron paramagnetic resonance (EPR), X-ray diffraction (XRD), conductivity measurement, cyclic voltammetry (CV), and elemental analyses. The molar conductance of oxovanadium(IV) complexes were found to be relatively low, depicting their non-electrolytic nature. The XRD patterns reveal the size of particles to be 47.53 nm and 26.28 nm for the two complexes in the monoclinic crystal system. The molecular structures, geometrical parameters, chemical reactivity, stability, and frontier molecular orbital pictures were determined by density functional theory (DFT) calculations. The theoretical vibrational frequencies and EPR -factors (1.98) were found to correlate well with the experimental values. A distorted square pyramidal geometry with C symmetry of the complexes has been proposed from experimental and theoretical results in a synergistic manner. The antimicrobial sensitivity of the ligands and their metal complexes assayed against four bacterial pathogens viz. and Typhi howed that the oxovanadium(IV) complexes are slightly stronger antibacterial agents than their corresponding Schiff base precursors. The binding affinities obtained from the molecular docking calculations with the receptor proteins of bacterial strains (2EUG, 3UWZ, 4GVF, and 4JVD) showed that the Schiff bases and their oxovanadium(IV) complexes have considerable capacity inferring activeness for effective inhibition. The molecular dynamics simulation of a protein-ligand (4JVD-HL) complex with the best binding affinity of -12.8 kcal/mol for 100 ns showed acceptable stability of the docked pose and binding free energy of -15.17 ± 2.29 kcal/mol from molecular mechanics-generalized Born surface area (MM-GBSA) calculations indicated spontaneity of the reaction. The outcome of the research shows the complementary role of computational methods in material characterization and provides an interesting avenue to pursue for exploring new triazole based Schiff's bases and its vanadium compounds for better properties.
报道了两种含1,2,4 - 三唑部分的新型席夫碱配体及其氧钒（IV）配合物的合成与表征。通过紫外 - 可见（UV - Vis）、傅里叶变换红外（FTIR）、质子核磁共振（H NMR）、电子顺磁共振（EPR）、X射线衍射（XRD）、电导率测量、循环伏安法（CV）和元素分析对配体及其配合物进行了研究。发现氧钒（IV）配合物的摩尔电导率相对较低，表明其非电解质性质。XRD图谱显示在单斜晶体系统中，两种配合物的颗粒尺寸分别为47.53 nm和26.28 nm。通过密度泛函理论（DFT）计算确定了分子结构、几何参数、化学反应性、稳定性和前沿分子轨道图像。发现理论振动频率和EPR因子（1.98）与实验值相关性良好。通过实验和理论结果协同提出了配合物具有C对称性的扭曲四方锥几何结构。对配体及其金属配合物针对四种细菌病原体即伤寒杆菌的抗菌敏感性测试表明，氧钒（IV）配合物作为抗菌剂比其相应的席夫碱前体略强。从与细菌菌株（2EUG、3UWZ、4GVF和4JVD）的受体蛋白的分子对接计算获得的结合亲和力表明，席夫碱及其氧钒（IV）配合物具有相当大的能力推断有效抑制的活性。对结合亲和力最佳为 - 12.8 kcal/mol的蛋白质 - 配体（4JVD - HL）复合物进行100 ns的分子动力学模拟，显示对接构象具有可接受的稳定性，并且通过分子力学 - 广义玻恩表面积（MM - GBSA）计算得到的结合自由能为 - 15.17±2.29 kcal/mol，表明反应具有自发性。研究结果显示了计算方法在材料表征中的互补作用，并为探索具有更好性能的新型基于三唑的席夫碱及其钒化合物提供了一个有趣的途径。
