Department of Chemistry, Faculty of Science, University of Douala, P.O. Box 24157, Douala, Cameroon.
Department of Chemistry, Higher Teacher Training College Bertoua, University of Ngaoundere, P.O Box. 652, Bertoua, Cameroon.
J Mol Graph Model. 2021 May;104:107830. doi: 10.1016/j.jmgm.2020.107830. Epub 2021 Jan 1.
In this paper, we have explored the bonding properties of a series of mononuclear half-sandwich nd anticancer complexes based on N∩O dendritic scaffolds (L) using two functionals (B3LYP and BP86) with generic basis set (LanL2DZ for transition metals (as well as halogen atoms) and 6-311 + G (d,p) for others atoms. The geometry optimization of structures have led to the adoption of the piano-stool environment and the formation of kings of intermolecular hydrogen bonding: CH … X (Cl,Br) (2.619-2.954) and CH...O (2.266-2.973 Å) interaction. The metal (M)-bromine bond distances have shown to be significantly higher than metal-chlorine ones. In chloride complexes, salicylaldimine ligand-Co (-3097.15 kJ/mol) and salicylaldimine ligand-Ir (-3436.78 kJ/mol) interactions are stronger. Except for cobalt complexes, the interaction energies are underestimated by B3LYP functional, by contrast B3LYP HOMO-LUMO gaps obtained are highly greater. The metal ion affinity (MIA) is increasing in the order: Ir<Rh<Co for both halogen ligands adopted, exception for picolinate and salicylaldimine ligands. Our results also show that the metal … oxygen, metal … nitrogen and metal … halogen interactions are closed-shell interaction. From the contribution of the ΔE term in the ranges 4.06-98.61% (X = Cl) and 10.29-99.87% (X = Br), the nature of the [Formula: see text] … X interaction turned out to be mainly dependent on the transition metal and halogen atom involved. The smallest back-donation observed for chloride complexes corresponding to the highest barrier to the formation of [MLCP]-X bond traduces that the fact that chloride complexes are the least reactive. In the majority of cases, larger donation is obtained compared to back-donation showing that the possibility of [Formula: see text] [Formula: see text] charge separation can be expected. For α rings of chloride complexes, B3LYP HOMA indexes are higher than those estimated by PB86 functional. Conversely, opposite results were found for their bromide counterparts.
在本文中，我们使用两种泛函（B3LYP 和 BP86）和通用基组（LanL2DZ 用于过渡金属（以及卤素原子）和 6-311+G（d，p）用于其他原子）研究了一系列基于 N∩O 树枝状支架（L）的单核半夹心钕抗癌配合物的键合性质。结构的几何优化导致采用钢琴凳环境和形成多种分子间氢键：CH…X（Cl，Br）（2.619-2.954）和 CH…O（2.266-2.973Å）相互作用。金属（M）-溴键距离明显高于金属-氯键距离。在氯化物配合物中，水杨醛亚胺配体-Co（-3097.15 kJ/mol）和水杨醛亚胺配体-Ir（-3436.78 kJ/mol）相互作用更强。除钴配合物外，B3LYP 泛函低估了相互作用能，而 B3LYP HOMO-LUMO 间隙则大大增加。金属离子亲合能（MIA）的顺序为：Ir<Rh<Co，对于两种卤素配体都是如此，除了 picolinate 和水杨醛亚胺配体。我们的结果还表明，金属…氧、金属…氮和金属…卤素相互作用是闭壳层相互作用。从ΔE 项的贡献来看，范围为 4.06-98.61%（X=Cl）和 10.29-99.87%（X=Br），[Formula: see text]…X 相互作用的性质主要取决于所涉及的过渡金属和卤素原子。对于形成[MLCP]-X 键的最高能垒，氯化物配合物的反馈最小，这表明氯化物配合物的反应性最低。在大多数情况下，与反馈相比，获得的供体更大，表明可以预期[Formula: see text] [Formula: see text]电荷分离的可能性。对于氯化物配合物的α环，B3LYP HOMA 指数高于 PB86 泛函估计的指数。相反，对于它们的溴化物对应物，则发现了相反的结果。
