Pavelka Matej, Simanek Milan, Sponer Jirí, Burda Jaroslav V
Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Prague 2, Czech Republic.
J Phys Chem A. 2006 Apr 13;110(14):4795-809. doi: 10.1021/jp056868z.
This work presents a systematic theoretical study on Cu(I) and Cu(II) cations in variable hydrogen sulfide-aqua-ammine ligand fields. These ligands model the biologically most common environment for Cu ions. Molecular structures of the complexes were optimized at the density functional theory (DFT) level. Subsequent thorough energy analyses revealed the following trends: (i) The ammine complexes are the most stable, followed by those containing the aqua and hydrogen sulfide ligands, which are characterized by similar stabilization energies. (ii) The most preferred Cu(I) coordination number is 2 in ammine or aqua ligand fields. A qualitatively different binding picture was obtained for complexes with H(2)S ligands where the 4-coordination is favored. (iii) The 4- and 5-coordinated structures belong to the most stable complexes for Cu(II), regardless of the ligand types. Vertical and adiabatic ionization potentials of Cu(I) complexes were calculated. Charge distribution (using the natural population analysis (NPA) method) and molecular orbital analyses were performed to elucidate the nature of bonding in the examined systems. The results provide in-depth insight into the Cu-binding properties and can be, among others, used for the calibration of bioinorganic force fields.
这项工作对可变硫化氢 - 水 - 氨配体场中的Cu(I)和Cu(II)阳离子进行了系统的理论研究。这些配体模拟了铜离子在生物学上最常见的环境。配合物的分子结构在密度泛函理论（DFT）水平上进行了优化。随后深入的能量分析揭示了以下趋势：(i)氨配合物最稳定，其次是含有水和硫化氢配体的配合物，它们具有相似的稳定能。(ii)在氨或水配体场中，最优选的Cu(I)配位数为2。对于具有H₂S配体的配合物，得到了定性不同的结合情况，其中4配位更受青睐。(iii)无论配体类型如何，4配位和5配位结构都属于Cu(II)最稳定的配合物。计算了Cu(I)配合物的垂直和绝热电离势。进行了电荷分布（使用自然布居分析（NPA）方法）和分子轨道分析，以阐明所研究体系中的键合性质。这些结果深入洞察了铜的结合特性，并且尤其可用于生物无机力场的校准。
