Quantum chemical study, spectroscopic investigations, NBO and HOMO–LUMO analyses of 3-aminoquinoline (3AQ) and [Ag(3AQ)2(TCA)] complex (TCA = Trichloroacetate)

• [Ag(3AQ)2(TCA)] complex is synthesized and characterized for the first time.
• The molecular structures of 3AQ and [Ag(3AQ)2(TCA)] are predicted using B3LYP method.
• Natural bond orbital (NBO) analysis has been performed on the studied compounds.
• Good correlations between the calculated and experimental 1H NMR spectra were obtained.
• The electronic spectra of the studied compounds are calculated using TD-DFT method.

The new [Ag(3AQ)2(TCA)]; (3AQ = 3-aminoquinoline and TCA = Trichloroacetate) complex is synthesized and characterized using elemental analysis, FTIR, NMR and mass spectroscopy. The molecular geometry, vibrational frequencies, gauge-including atomic orbital (GIAO) 1H chemical shift values of the free and coordinated 3AQ in the ground state have been calculated by using DFT/B3LYP method. The TD-DFT results of the [Ag(3AQ)2(TCA)] complex showed a π–π* transition band at 240.3–242.6 nm (f = 0.1334–0.1348) which has longer wavelength and lower absorption intensity than that for the free 3AQ (233.2 nm, f = 0.3958). Dipole moment, polarizability and HOMO–LUMO gap values predicted better nonlinear optical properties (NLO) for the [Ag(3AQ)2(TCA)] than the 3AQ ligand. NBO analysis has been used to predict the most accurate Lewis structure of the studied molecules. The energies of the different intramolecular charge transfer (ICT) interactions within the studied molecules were estimated using second order perturbation theory.

The frontier molecular orbitals (FMO) of 3AQ and [Ag(3AQ)2(TCA)] complex.Figure optionsDownload as PowerPoint slide