Three new organotin(IV) complexes, [Me₃Sn(H₂L)]₂ (1), Bu₃Sn(H₂L) (2), and [(Bu₂Sn(H₂L))₂O]₂ (3) were synthesized by the reaction of 2-[4-hydroxy-3-((2-hydroxyethylimino)methyl)phenylazo]benzoic acid (H₃L) with appropriate alkyltin(IV) precursors. The complexes were characterized by elemental analysis, IR, and multinuclear (¹H, ¹³C and ¹¹⁹Sn) NMR spectroscopy. Further, the complex 1 was analyzed by single-crystal X-ray analysis. It displays a 24-membered cyclic dimeric Me₃Sn^IV(H₂L) unit where the ligand act as a bridging framework using its carboxylate-O and phenoxy-O atoms. The Sn(IV) adopts distorted trigonal-bipyramidal geometry. In the solution state, the structures were determined by ¹¹⁹Sn-NMR spectroscopy, and the complexes 1 and 2 have distorted tetrahedral geometry, whereas complex 3 shows distorted trigonal-bipyramidal geometry around the tin centres. The Hirshfeld surface analysis and DFT calculations, together with a topological analysis of the electron density distribution in the crystal structure of complex 1, indicate that its molecular packing determined by various noncovalent interactions, including stacking and hydrogen bonding. The antibacterial studies of the ligand and the complexes (1–3) against gram-negative bacteria viz. Klebsiella pneumoniae (A),Vibrio cholerae (M) and Shigella boydii (Q) and gram-positive bacteria viz.Staphylococcus aureus (J), Streptococcus pneumonia (K) are promising and the compounds can be treated as potential common antibacterial materials.

Four new transition metal complexes (1-4) were successfully synthesized through the reaction of M(NO3)2·nH2O (M = Ni, Co, Cd or Zn; n = 6 for Ni, Co, Zn; n = 4 for Cd) with 1,1-dicyanoethylene-2,2-dithiolate (i-MNT2–) and p-phenylenediamine (PPD) ligands. The syntheszed metal complexes were characterized by CHN-analysis, electronic, FTIR and 1H NMR spectroscopic techniques. The electronic transition investigations reveals six coordinate octahedral geometry for Ni(II), distorted octahedral for Co(II), four coordinate tetrahedral geometry for Cd(II) and Zn(II) complexes. All the four metal complexes displayed a significant red shift in the absorption maximum, suggesting their successful assembly. The luminescence behaviour exhibited the prominent fluorescence within the visible range. The current-voltage characteristics revealed that complexes 2 and 3 exhibited ohmic behaviour, displaying a linear curve. On the other hand, complexes 1 and 4 initially maintained a low conducting state (OFF state) until a specific voltage threshold (VTh), beyond which the current sharply increased, transitioning to a higher current state (ON state). The FESEM images of the metal complexes strongly indicated a nano-scale aggregated structure. In terms of antibacterial activity, complexes 3 and 4 demonstrated promising efficacy against various bacterial strains, with complex 3 being particularly potent. The fungicidal activity of all four metal complexes was remarkable against Magnaporthe grisea, Cochliobolus miyabeanus and Synchitrium endobioticum, however, no fungicidal activity was found against Trichophyton mentagrophytes and Candida albicans.

The objective of this study was to utilize paper chromatography (PC) as a cost-effective and accessible method to impart fundamental principles of chromatography to undergraduate students in introductory inorganic chemistry courses. The experiments focused on detecting and separating metal ions from various groups in the analytical table. Specifically, the study aimed to educate students on the separation and identification of metal ions, comparing color spots and retention factor values, and understanding the influence of alkalinity during metal ion oxidation. Paper chromatography and planar chromatography share the use of solid, flat stationary phases. In this study, Whatman quantitative grade 41 filter paper was employed as the stationary phase. Minimal sample quantities were utilized for qualitative analysis. Through the use of different eluting agents, PC was employed to separate and identify transition metal ions such as (Fe3+ & Cr3+) in group III, (Pb2+ & Cu2+) in group II, Co2+ & Ni2+ in group IV, (Co2+ & Cu2+) in group IV and II, (Cu2+ & Fe3+) in group II and III, and (Mo6+ & W6+) in group VI, based on their distinct color spots and retention factor (Rf) values. This qualitative investigation enabled undergraduate students to appreciate the efficacy of PC in identifying and separating pairs of metal ions through observation of different color spots and their corresponding Rf values.

The mixed ligand complexes of Co(II) metal ions with some heterocyclic nitrogen bases along with 1-cyano-1-carboethoxyethylene-2,2-dithiolate ion (CED2−) of the compositions, Co(N-N)(CED)·2H2O [N-N = o-phen/2,2′-bipy] and Co(N-N)(CED)L2 [N-N = o-phen/2,2′-bipy, CED2– = 1-cyano-1-carboethoxyethylene-2,2-dithiolate, L = γ-picoline (γ-pic), β-picoline (β-pic), α-picoline (α-pic), pyridine (py)] were characterized and isolated by analytical data as well as physico-chemical methods for example infrared spectroscopy, electronic, magnetic susceptibility, molar conductance. The complexes are soluble in coordinating solvents like DMSO and DMF and decompose below 250 ºC. The synthesized complexes in DMF solution are non-electrolytic as shown by their molar conductance data. The calculated magnetic moments suggest that the synthesixed cobalt(II) compounds are paramagnetic and produce a low-spin environment for the Co(II) ion. Thermal studies reveal that Co(N-N) contains two coordinated water molecules (CED)·2H2O. Electronic spectra of cobalt(II) complexes with mixed ligands in DMF solution are consistent with distorted octahedral stereochemistry. The IR studies indicates that the CED2- ion exhibits bidentate chelating behaviour and that heterocyclic nitrogen donors coordinate to Co atoms (II). Reaction with heterocyclic nitrogen donors (γ-picoline, β-picoline, α-picoline, pyridine) signifying the ligand exchange reaction.

Six novel nickel(II) complexes were synthesized using Nickel(II) nitrate hexahydrate, ortho-phenanthroline (o-phen), or 2,2ʹ-bipyridine (bipy) and 1-cyano-1-carboethoxyethylene-2,2-dithiolate (CED2-) ligands through various stoichiometric ratios, showing good solubility across organic solvents. Weight loss experiments suggested water of crystallization, and molar conductance studies indicated electrolytic behavior for some complexes. UV-visible absorption spectra confirmed octahedral coordination around Ni(II), and fluorescence studies showed excitation-dependent emissions. IR confirmed structural details, and current-voltage (I-V) measurements demonstrated resistive switching behavior in memory devices, with compounds exhibiting write-once-read-many (WORM) characteristics. Cytotoxicity studies showed noteworthy activity against the A-549 lung cancer cell line, especially for compounds 1, 4, and 6. Antifungal assays revealed notable activity against certain fungi, enhanced by the metal-ligand interaction increasing lipophilicity. These findings highlight the potential of the complexes in memory devices, anticancer treatments, and antifungal applications.