Halogen-induced electronic modulation and nonlinear optical enhancement in a 6-iodopyridine-2-carboxylate Ni(II) complex: An experimental and DFT study
JOURNAL OF MOLECULAR STRUCTURE, vol.1356, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 1356
- Publication Date: 2026
- Doi Number: 10.1016/j.molstruc.2025.145068
- Journal Name: JOURNAL OF MOLECULAR STRUCTURE
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC
- Ondokuz Mayıs University Affiliated: Yes
Abstract
A nickel(II) coordination complex, [Ni(6Ipca)2(4,4dmdpy)], was synthesized using 6-iodo-pyridine-2-carboxylic acid (6IpcaH) and 4,4 '-dimethyl-2,2 '-dipyridyl (4,4dmdpy). The crystal structure, determined via single-crystal Xray diffraction, reveals a distorted octahedral geometry around the Ni(II) center. The thermal stability of Ni(II) complex was studied by employing TG-DTA analysis. The structural framework was corroborated by DFT (B3LYP/LanL2DZ) calculations, which also supported vibrational modes observed in FT-IR spectra. Frontier molecular orbital (FMO) and natural bond orbital (NBO) analyses demonstrated enhanced electron delocalization and significant ligand-to-metal charge transfer. Static and frequency-dependent first-and second-order hyperpolarizability parameters ((3 and gamma) revealed substantial nonlinear optical (NLO) responses, with the complex exhibiting higher gamma(-w;w,0,0) (228.45 x 10-36 esu) values compared to its free ligands. Furthermore, molecular docking simulations against CDK8 kinase showed improved binding affinity (-6.29 kcal/mol, Ki = 24.35 mu M) for the Ni(II) complex relative to its uncoordinated ligands, suggesting potential antitumor relevance. These findings position the synthesized Ni(II) complex as a promising multifunctional candidate for NLO applications and biomedical research.