Spectral and structural density functional theory on 4-ethyl and 4-(p-tolyl)-1-(pyridin-2-yl)thiosemicarbazides and their Pd(II) complexes

► Quantum calculations of geometry, IR, 1H NMR and NBO of ligands and their Pd(II). ► The optimized structures of the ligands confirmed the intramolecular H-bond. ► The DFT calculated spectral data showed good agreement with experimental data. ► The NBO confirmed the two bonds Pd-S and Pd-N1 (donation of electron from N to Pd).