Ahmed Mukhtar, Malhotra Sumit Sahil, Alsubaie Abdullah Saad, El-Bahy Salah M, Mohapatra Ranjan Kumar, Ansari Azaj
Department of Chemistry, Central University of Haryana, Mahendergarh, 123031, India.
Department of Physics, College of Khurma University College, Taif University, 21944, Taif, Saudi Arabia.
J Mol Model. 2025 Feb 5;31(3):75. doi: 10.1007/s00894-025-06296-w.
In the present work, DFT/TDDFT techniques is used to analyze structure, bonding, reactivity and electronic transitions of quercetin, morin, myricetin with their metal (Cu and Zn) complexes. In order to comprehend metal complexes and ligands reactivity patterns, we calculated energy gaps between frontier molecular orbitals. Global reactivity characteristics, such as ionization potential, electronegativity (χ), hardness (η), softness (S), electrophilicity index (ω) electron affinity, and chemical potential (μ), were computed based on the FMO energies. Molecular electrostatic potential (MEP) maps were used to identify nucleophilic and electrophilic sites in complexes. Within the examined complexes, TDDFT and NBO analysis shed light on bonding, electronic transitions and stabilizing interactions. Ligands morin, myricetin, and quercetin exhibited higher HOMO-LUMO gap than their corresponding metal complexes, suggesting electron transfer may be faster in the metal complexes. The metal complexes displayed more negative electrostatic potentials. The absorption spectra of the ligands ranged from 258 to 360 nm, whereas their complexes exhibited a broader range from 252 to 1035 nm. These spectra provided important insights into charge transfer and electronic transitions, enhancing our knowledge of electronic and bonding characteristics of such compounds.
G16 software is used to optimize all species. B3LYP functional was employed in combination with LanL2DZ basis set for Cu and Zn, and 6-311G(d,p) basis set for other atoms (C, H and O). Natural bond orbital examination was conducted in order to investigate interactions between the filled orbitals of one unit and empty orbitals of other unit. ORCA software was utilized to compute spectral features, incorporating ZORA method to account for relativistic effects. TDDFT studies is carried out using B3LYP functional to calculate excitation energies.
在本研究中，采用密度泛函理论/含时密度泛函理论（DFT/TDDFT）技术分析槲皮素、桑色素、杨梅素及其金属（铜和锌）配合物的结构、键合、反应活性和电子跃迁。为了理解金属配合物和配体的反应模式，我们计算了前线分子轨道之间的能隙。基于前线分子轨道能量计算了全局反应性特征，如电离势、电负性（χ）、硬度（η）、软度（S）、亲电性指数（ω）、电子亲和势和化学势（μ）。利用分子静电势（MEP）图确定配合物中的亲核和亲电位点。在所研究的配合物中，TDDFT和自然键轨道（NBO）分析揭示了键合、电子跃迁和稳定相互作用。配体桑色素、杨梅素和槲皮素的最高占据分子轨道（HOMO）-最低未占据分子轨道（LUMO）能隙高于其相应的金属配合物，这表明金属配合物中的电子转移可能更快。金属配合物表现出更负的静电势。配体的吸收光谱范围为258至360nm，而它们的配合物表现出更宽的范围，从252至1035nm。这些光谱为电荷转移和电子跃迁提供了重要的见解，增强了我们对此类化合物的电子和键合特征的认识。
使用G16软件优化所有物种。对于铜和锌，采用B3LYP泛函并结合LanL2DZ基组，对于其他原子（碳、氢和氧）采用6-311G(d,p)基组。进行自然键轨道研究以研究一个单元的填充轨道与另一个单元的空轨道之间的相互作用。利用ORCA软件计算光谱特征，采用零级正则近似（ZORA）方法考虑相对论效应。使用B3LYP泛函进行TDDFT研究以计算激发能。
