New cobalt(II), copper(II), and zinc(II) Schiff metal complexes were synthesized by the condensation reaction of 4-nitrobenzene-1,2-diamine with 3-4-(diethylamino)-2-hydroxybenzaldehyde. Fourier transform infrared, nuclear magnetic resonance, ultraviolet-visible, electron paramagnetic resonance, and high-resolution electrospray ionization mass spectrometry and powder X-ray diffraction were used to characterize the synthesized H₂L and its metal complexes. Conductance measurements, magnetic moment estimation, and metal estimation have all been determined and discussed. The electrochemical properties of the synthesized compounds have been determined and discussed using cyclic voltammetry. The molecular structures of H₂L and its metal complexes have been optimized using the B3LYP functional and the 6-31G (d,p) basis set, and their parameters have been discussed. The quantum chemical properties of these synthesized compounds have been predicted through charge distribution and molecular orbital analysis. The biological properties of the synthesized compounds' antioxidant, antifungal, and antibacterial activity have been studied and discussed. Furthermore, H₂L and its complexes have been docked with HER2-associated target proteins in breast cancer.

The vibrational spectra including FT-IR and FT-Raman for 2,5-dichloro-p-xylene (DCPX) have been recorded. All the energies, the geometry of the compound and vibrational frequencies of (DCPX) have been calculated using density functional theory (DFT/B3LYP) method coupled with 6-31G* and 6-311+G** functionals. The occurrence of charge transfer was known from the HOMO–LUMO energy gap of DCPX. In order to find out the electronic excitation energies, oscillator strength and nature of the respective excited states, the closed-shell singlet calculation method has been utilized for DCPX. The values of the total dipole moment (µ) and the first order hyperpolarizability (β) of DCPX have been investigated. The non-linear optical (NLO) behavior of DCPX has been identified from the results of hyperpolarizability values.

Important biological compounds, namely, methyl 3-amino-4-(4-bromophenyl)thiophene-2-carboxylate (BPTC) and methyl 3-amino-4-(4-chlorophenyl)thiophene-2-carboxylate (CPTC), were characterized using complementary techniques of Fourier transform infrared (FT-IR), Raman spectroscopy. Nuclear magnetic resonance spectroscopy (NMR) confirmed the structural features, while Ultra Violet–Visible Spectroscopy was used to investigate the electronic properties of both compounds. The quantum chemical calculations for both compounds were performed using the DFT/B3LYP functional with the 6-311++G(d,p) basis set. This study computes electrostatic potential observation, electron localization function (ELF) assessment, and atoms-in-molecules (AIM) analysis. In the present investigation, the global hardness, chemical softness, electrophilicity, nucleophilicity indices, and dipole moment of both compounds were calculated. In addition, a molecular docking analysis was conducted to determine the binding potential of target molecules with protein tyrosine phosphatase. A 200-ns molecular dynamics (MDs) simulation had been performed to assess the compound’s binding stability.