In this article, we have synthesized two contemporary ortho-vanillin-based Salen-type ligands (H₂L¹/H₂L²) characterized by modern spectroscopic tools. EDX analysis supports the elemental composition (C, N, O, and Br). SEM examined the morphology of the synthesized compounds. The molecular geometry was optimized in the gas phase using B3LYP-D3/6-311G (d, p) level. The global reactivity parameters, HOMO-LUMO energy gap (Δ), atomic properties, MESP, and ADME/T, vividly explore the chemical reactivity and toxicity of two Salen-type ligands. The DFT simulated IR/NMR characterized essential structural assignments, and UV-Visible spectra were employed to predict the optical properties. The article demonstrated in silico molecular docking against the Gm + ve Bacillus subtilis (6UF6), and Gm -ve Proteus Vulgaris establishes the ligand binding ability with essential amino acids through conventional H-bonding or other significant interactions. The docking simulation is compared for two compounds better than the control drugs and confirms the antimicrobial activity. The theoretical drug-like properties have been explored in-depth by ADME/T using the SWISSADME database. The analysis estimated the molecule's lipophilicity, the consensus P0/W, and water solubility. Thus, using various pharmaco-logical parameters, toxicity explains where the electron-withdrawing Br group plays a more toxic effect in H₂L² than in H₂L¹.

Three new heteronuclear nickel(II)/cadmium(II) complexes, [(SCN)(Cl)Cd(L)Ni(DMF)₂] (1), [(SCN)(CH₃CO₂)Cd(L)Ni(CH₃OH)₂] (2) and [(SCN)(Cl)Cd(L)Ni(NH₂CH₂CH₂CH₂NH₂)]_n (3) {where H₂L = N,N′-bis(3-ethoxy-salicylidene)propane-1,3-diamine is a N₂O₄ compartmental Schiff base}, have been synthesized and characterized. The structures of the complexes have been confirmed by single crystal X-ray diffraction studies. In each complex, nickel(II) is placed in the inner N₂O₂ environment and cadmium(II) is placed in the outer O₄ compartment of the compartmental Schiff base. Furthermore, the importance of unconventional C–H⋯π (chelate) interactions in the solid state of both complexes and C–H⋯π (thiocyanate) interaction in complex 2 has been described by means of DFT and MEP calculations and characterized using NCI plots. All complexes show photoluminescence at room temperature upon irradiation by ultraviolet light. The lifetimes of excited states are in the range of 2–6 ns.

This work contemplates synthesizing M-SCN crystal compounds (M = Hg/Pb/Cu) in the presence of respective metal salts and exogenous ancillary SCN⁻ ion by slowly evaporating the mixed solvent (CH₃OH + ACN). The complexes were characterized by spectroscopy, SEM/EDX, and X-ray crystallography. The Hg-Complex, Pb-Complex, and Cu-Complex crystallize in the monoclinic space group (Z = 2/4). The crystal packing fascinatingly consists of weak covalent bonding and Pb⋯S contacts of tetrel type bond. Here are the incredible supramolecular topographies delineated by the Hirshfeld surface and 2D fingerprint plot. The B3LYP/6–311++G (d, p) level calculations in the gas phase optimized the compound's geometry. The energy difference (Δ) between HOMO-LUMO and global reactivity parameters investigates the complex's energetic activity. MESP highlights the electrophilic/nucleophilic sites and H-bonding interactions. Molecular docking was conceded with the Gram- + ve bacterium Bacillus Subtilis (PDB ID: 6UF6) and the Gram-ve bacterium Proteus Vulgaris (PDB ID: 5HXW) to authenticate the bactericidal activity. ADME/T explains the various pharmacological properties. In addition, we studied the antibacterial activity with MIC (μg/mL) values and time-kill kinetics against Staphylococcus aureus (ATCC 25923) and Bacillus subtilis (ATCC 6635) as Gram-positive, Pseudomonas aeruginosa (ATCC 27853) and Escherichia coli (ATCC 25922) as Gram-negative bacteria.

A facile method for synthesizing trinuclear zinc(II) complexes with compartmental reduced Schiff bases has been described. Five such complexes, [{(N₃)Zn(L¹)}₂Zn] (1), [{(SCN)Zn(L¹)}₂Zn] (2), [{(SCN)Zn(L²)}₂Zn] (3), [{(N₃)Zn(L²)}₂Zn] (4) and [{(N₃)Zn(L³)}₂Zn]·CH₂CL₂ (5) where H₂L¹ = 2,2′-[(1,3-propanediyl)bis(iminomethylene)]bis[6-ethoxyphenol], H₂L² = 2,2′-[(2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)]bis[6-methoxyphenol] and H₂L³ = 2,2′-[(2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)]bis[6-ethoxyphenol], were synthesized and characterized by elemental and spectral analyses. X-ray crystallographic analyses have confirmed their structures. All complexes may be used as sensors for the detection of nitroaromatics in DMF via turn-off fluorescence response.

Four hetero-dinuclear nickel(II)/lead(II) complexes have been synthesized and characterized. Their structures have been confirmed by single crystal X-ray diffraction studies. In each complex, nickel(II) is placed in the inner N₂O₂ compartment and lead(II) in the outer O₂O₂′ compartment of the respective Schiff base. In complexes 1, 3 and 4, lead(II) centres are hemidirectionally coordinated, and thus are well suited for establishing tetrel bonding interactions which have been investigated thoroughly by means of DFT calculations.