Crystal Structure, Spectroscopic (FT-IR and UV-Vis), Nonlinear Optical, and Molecular Docking Analyses of a Fluorinated Picolinate Silver(I) Complex

Abstract

The synthesis, structural elucidation, and nonlinear optical (NLO) evaluation of a novel Ag(I) coordination complex, [Ag(6Fpca)<inf>2</inf>], where 6FpcaH represents 6-fluoropyridine-2-carboxylate ligand, are reported. Single-crystal XRD analysis revealed a distorted square planar geometry with Ag-N=2.245 Å and Ag-O=2.480 Å. The HOMO-LUMO energy gap significantly decreased from 5.0535 eV in the free 6FpcaH ligand to 4.4590 eV in the Ag(I) complex. The dipole moment increased from 6.21 D to 13.44 D, and the static polarizability (α) rose from 1.04 × 10-23esu to 3.27 × 10-23 esu. The first-order hyperpolarizability (β) increased almost tenfold from 1.65 × 10-30 esu in the ligand to 16.70 × 10-30 esu in the complex, while the frequency-dependent β(-ω;ω,0) reached 31.91 × 10-30 esu at 532 nm and 26.64 × 10-30 esu at 1064 nm. Likewise, the second-order hyperpolarizability (γ) rose to 1.81 × 10-34 esu at 1064 nm. Hirshfeld surface analysis confirmed that H···F (18.8 %) and H···O (26.6 %) interactions dominate crystal packing, promoting dipole alignment crucial for NLO performance. These combined experimental and theoretical findings demonstrate the remarkable enhancement of both static and dynamic NLO responses in the [Ag(6Fpca)<inf>2</inf>] complex, establishing it as a promising candidate for next-generation photonic and optoelectronic applications. © 2025