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Density functional theory investigation of the binding interactions between phosphoryl, carbonyl, imino, and thiocarbonyl ligands and the pentaaqua nickel(II) complex: Coordination affinity and associated parameters
Author(s) -
Costa Leonardo M.,
Stoyanov Stanislav R.,
Damasceno Raimundo N.,
de M. Carneiro José Walkimar
Publication year - 2013
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.24524
Subject(s) - chemistry , substituent , ligand (biochemistry) , nickel , density functional theory , metal , stereochemistry , covalent bond , octahedron , crystallography , computational chemistry , crystal structure , organic chemistry , biochemistry , receptor
Density Functional Theory (UB3LYP/6‐311++G(d,p)) calculations of the affinity of the pentaaqua nickel(II) complex for a set of phosphoryl [OP(H)(CH 3 )(PhR)], imino [HNC(CH 3 )(PhR)], thiocarbonyl [SC(CH 3 )(PhR)] and carbonyl [OC(CH 3 )(PhR)] ligands were performed, where RNH 2 , OCH 3 , OH, CH 3 , H, Cl, CN, and NO 2 is a substituent at the para ‐position of a phenyl ring.The affinity of the pentaaqua nickel(II) complex for these ligands was analized and quantified in terms of interaction enthalpy (Δ H ), Gibbs free energy (Δ G 298 ), geometric and electronic parameters of the resultant octahedral complexes. The Δ H and Δ G 298 results show that the ligand coordination strength increases in the following order: carbonyl < thiocarbonyl < imino < phosphoryl. This coordination strength order is also observed in the analysis of the metal‐ligand distances and charges on the ligand atom that interacts with the Ni(II) cation. The electronic character of the substituent R is the main parameter that affects the strength of the metal‐ligand coordination. Ligands containing electron‐donating groups (NH 2 , OCH 3 , OH) have more exothermic Δ H and Δ G 298 than ligands with electron‐withdrawing groups (Cl, CN, NO 2 ). The metal‐ligand interaction decomposed by means of the energy decomposition analysis (EDA) method shows that the electronic character of the ligand modulates all the components of the metal‐ligand interaction. The absolute softness of the free ligands is correlated with the covalent contribution to the instantaneous interaction energy calculated using the EDA method. © 2013 Wiley Periodicals, Inc.