da Silva Victor Hugo Malamace, Quattrociocchi Daniel Garcez S, Stoyanov Stanislav R, Carneiro José Walkimar de Mesquita, da Costa Leonardo Moreira, Ferreira Glaucio Braga
Escola de Engenharia, Universidade Federal Fluminense, Rua Passos da Pátria 156, Niterói, RJ, 24210-253, Brazil.
Programa de Pós-gradução em Química, Departamento de Química Inorgânica, Departamento de Química Orgânica, Instituto de Química, Universidade Federal Fluminense, Outeiro de São João Batista s/n, Niterói, RJ, 24020-141, Brazil.
J Mol Model. 2018 Jan 8;24(1):39. doi: 10.1007/s00894-017-3571-x.
A series of B3LYP/6-311+G(d,p) calculations of the affinity of monodentate ligands for [Cd(HO)] are performed. Three types of ligands containing O (phosphine oxide, lactam, amide, carboxylic acid, ester, ketone, aldehyde, ether, halohydrin, enol, furan), N (thiocyanate, amine, ammonia, azide), and S (thioester, thioketone, thiol, thiophene, disulfide) interacting atoms are investigated. The results show that phosphine oxide has the largest affinity for the cadmium cation due to the polarization of the P=O bond. As the P atom has a large atomic radius, the O atom can polarize the electronic cloud enhancing its amount of electronic charge and favoring the interaction with Cd. The affinity order found is phosphine oxide > thioester > lactam > amide > carboxylic acid > ester > thioketone > ketone > thiocyanate > amine > ammonia > aldehyde > ether > thiol > thiophene > enol > halohydrin > disulfide > azide > furan ligands. These results were also corroborated by the functional M06-2X. The electronic effects (resonance and induction) of neighboring groups of the interacting atom modulate the strength of metal-ligand binding. For almost all the O-donor ligands the electrostatic component has the same magnitude as the covalent term, while for the N- and S-donor ligands the covalent term is predominant. The polarization term accounts for twice the exchange term as part of the covalent component. The dispersion term varies less than 2 kcal mol for the complexes analyzed. The Pauli repulsion term is correlated with the metal ligand distance, increasing in the compounds with decreased metal-ligand bond length. The charge between the interacting atoms is also strongly correlated with both the interacting strength and the electrostatic interaction component. The natural bond orbital analysis highlights correlations of the bond order, and S and P contributions of the interacting metal-ligand orbital with the coordination strength. Graphical abstract The affinity of 20 monodentate ligands with different functional groups for the [Cd(HO)] cation is calculated based on the interaction enthalpy and Gibbs free energy for the substitution of one water molecule from the fully hydrated cation. The affinity is correlated with geometric, electronic, and energetic parameters of the ligands and the complexes as well as with energy decomposition and natural bond order analyses results.
进行了一系列关于单齿配体与[Cd(HO)]亲和力的B3LYP/6 - 311+G(d,p)计算。研究了三种含有与镉相互作用原子的配体类型，分别为含有O（氧化膦、内酰胺、酰胺、羧酸、酯、酮、醛、醚、卤代醇、烯醇、呋喃）、N（硫氰酸盐、胺、氨、叠氮化物）和S（硫酯、硫酮、硫醇、噻吩、二硫化物）的配体。结果表明，由于P=O键的极化作用，氧化膦对镉阳离子具有最大的亲和力。由于P原子具有较大的原子半径，O原子能够极化电子云，增加其电子电荷量，有利于与Cd的相互作用。发现的亲和力顺序为：氧化膦>硫酯>内酰胺>酰胺>羧酸>酯>硫酮>酮>硫氰酸盐>胺>氨>醛>醚>硫醇>噻吩>烯醇>卤代醇>二硫化物>叠氮化物>呋喃配体。这些结果也得到了M06 - 2X泛函的证实。相互作用原子相邻基团的电子效应（共振和诱导）调节金属 - 配体结合的强度。对于几乎所有的O供体配体，静电成分与共价项的大小相同，而对于N供体和S供体配体，共价项占主导。极化项作为共价成分的一部分，是交换项的两倍。对于所分析的配合物，色散项的变化小于2 kcal/mol。泡利排斥项与金属 - 配体距离相关，在金属 - 配体键长减小的化合物中增大。相互作用原子之间的电荷也与相互作用强度和静电相互作用成分密切相关。自然键轨道分析突出了键级以及相互作用的金属 - 配体轨道的S和P贡献与配位强度的相关性。图形摘要基于从完全水合阳离子中取代一个水分子时的相互作用焓和吉布斯自由能，计算了20种具有不同官能团的单齿配体与[Cd(HO)]阳离子的亲和力。该亲和力与配体和配合物的几何、电子和能量参数以及能量分解和自然键序分析结果相关。
