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• Synthesis of some new mixed ligand metal complexes. • Characterization of FEB, para and their metal complexes with different techniques. • Optimized geometries for the new complexes were done using DFT. • Evaluation of antibacterial, antioxidant and molecular docking activities for mixed ligand metal complexes was done. The synthesized mixed ligand metal complexes were achieved by a combination of febuxostat (2-(3-cyano-4-isobutyloxyphenyl)-4-methyl-5-thiazolecarboxylic acid) (FEB) and paracetamol (4‑hydroxy acetanilide) (Para) together with crucial biologically relevant elements. These elements, including Co(II), Cu(II), Zr(IV), and Ni(II) chlorides, play important roles in various biological systems and mechanisms, such as antioxidant, antimicrobial systems, and contribute to diverse functions and structures. To identify chemical formulae and structures of synthesized complexes, physical-analytical, spectroscopic (XRD, FT-IR, ESR, 13C NMR, 1H NMR, and UV-visible), mass spectrometry (MS), TG-DTG studies were used and supported by computational approaches. FT-IR and 1H NMR data revealed that FEB chelated through sulfur of thiazole ring as a mono-negative bidentate type and deprotonated oxygen of carboxylate group, according to lack of characteristic band at 1677 cm−1 and signal at δ = 13.37 ppm (-OH COOH), whereas Para chelated through nitrogen and oxygen of amide group as a neutral bidentate ligand. Magnetic moment and electronic spectra data revealed that complexes have an octahedral structure. The optical band gap (E g) for our compounds was calculated and according to E g values, all complexes were semi-conductors and fell into the class of solar materials compared with FEB and Para. XRD pattern showed the monoclinic polycrystalline structure for all compounds except the Zr(IV) complex was amorphous. Kinetic parameters of the thermal decomposition stages were calculated. DFT was utilized to confirm bonding mode for FEB and Para with metal ions and according to calculations of energy band gap (ΔE) of complexes, Cu(II) complex with smaller ΔE is more reactive but, Zr(IV) complex with higher ΔE is less reactive than FEB and Para. The antibacterial activity of FEB, Para, and their complexes were tested against two G-ve and three G +ve bacteria. Co(II) complex displayed remarkable effectiveness and high significance against all strains of bacteria, compared with other compounds tested. All compounds demonstrated antioxidant effects, Cu(II) and Zr(IV) show greater antioxidants than parent ligands with IC 50 values 0.040 and 0.057 mg/mL. The binding pattern and active site of all compounds were put through molecular docking studies and compared with empirical biological data. The synthesized metal complexes from febuxostat (FEB) and paracetamol (Para) identified by spectroscopic techniques (FT-IR, ESR, XRD, 1H NMR and UV–visible), mass spectrometry (MS), TG-DTG. The antibacterial activities were examined. The compounds have been tested for antioxidant activity. We performed molecular docking studies for our compounds. [Display omitted] [ABSTRACT FROM AUTHOR]

• Novel Co(II) (C1), Ni(II) (C2), & Cu(II) (C3) mixed-ligand complexes have been synthesized. • Their antibacterial, antifungal & anti-inflammatory efficacy have been the focus of recent studies. • The C1, C2, and C3 complexes were found to be more potential anti-inflammatory candidates than the free ligands. • DFT & molecular docking results were correlated with in vitro activities & debated. Here, we combine the simple and readily synthesized azo-ligand [1-((4-Hydroxyphenyl)azo)-2-naphthalenol (PNP)] with 8-hydroxyquinoline (QPH) to develop and synthesize novel Co(II) (C1), Ni(II) (C2), and Cu(II) (C3) complexes. Their antibacterial, antifungal, and anti-inflammatory efficacy had been the focus of recent studies. This objective was reached by first synthesizing and characterizing novel C1, C2, and C3 complexes using elemental analysis, mass spectra, Fourier-transform infrared, electronic spectra, magnetic, Thermal, and molar ratio analysis. Octahedral structures were identified for the C1, C2, and C3 complexes. Quantum chemical characteristics and an optimized molecular structure for each substance were calculated using Density Functional Theory (DFT). To find out whether these substances are efficient in stopping the diffusion of dangerous microorganisms that are the most popular environmental pollutants, a disc diffusion check was carried out. All complexes demonstrated significantly larger inhibition zones (IZ) against both Gram-negative and Gram-positive bacteria compared to free ligands, with increases ranging from 70 % to 134 %. Against fungal strains, C2 and C3 showed the most significant enhancements, exhibiting up to 202 % increase in IZ compared to QPH and PNP. All complexes displayed reductions in minimum inhibitory concentration (MIC) compared to the free ligands against both bacteria and fungi. The most notable reductions were observed against Gram-negative bacteria, with complexes C1-C3 achieving up to 50 % reduction in MIC compared to QPH and PNP. Against fungal strains, complexes C2 and C3 generally showed better activity, with up to a 25 % reduction in MIC compared to the free ligands. Furthermore, the Egg albumin denaturation technique was studied to assess the anti-inflammatory activity. At a concentration of 10 %, C3 exhibited the highest activity at 83.26 %. As the concentration increased to 50 %, C3 maintained its superiority at 83.42%, followed closely by C2 at 78.39 %. At 100 %, C3 again displayed the highest activity at 84.13 %, while C2 and C1 showed comparable activity. Remarkably, at higher concentrations (250 % and 500 %), C3 consistently outperformed all other compounds, reaching an impressive antioxidant activity of 86.29 % at 250 % concentration. The antibacterial, antifungal, and anti-inflammatory activity was assisted by molecular docking investigation against 5JQ9 and 6CLV from Escherichia coli and Staphylococcus aureus , and COX-2 (5IKT) as anti-inflammatory target enzyme, which confirms the bioactivity behavior. In the interaction with 5JQ9, 6CLV, and 5IKT, C3 displayed strong H-donor and ionic interaction with (GLY42 and ASP85), (GLY42 and ASP85) and (CYS41 and GLY45). Notably, C3 consistently exhibited strong interactions across all three receptors, emphasizing its potential as an effective compound. These quantitative results provide valuable insights into the molecular interactions and binding affinities, supporting the bioactivity behavior observed in the experimental assays. In the end, DFT and molecular docking results were correlated with in vitro activities and debated. [Display omitted] [ABSTRACT FROM AUTHOR]

• Reported the synthesis and crystal structure two magnesium porphyrins [Mg(TDMPP)(H 2 O) 2 ], 1 and [Mg(TDMPP)(pyz) 2 ], 2 where TDMPP = 5,10,15,20-tetrakis(3,5-dimethoxyphenyl)porphyrin and pyz = pyrazine. • In compound [Mg(TDMPP)(pyz) 2 ] two pyrazine ligands are coordinated to the metal magnesium forming a hexacoordinated compound. • Theoretical calculations like structure optimization, calculation of energy of molecular orbitals and simulation of electronic spectra were performed. • The HOMO-LUMO energy gap in 2 (2.53 eV) is slightly lower than 1 (2.56 eV) which supports the redshift of UV–Vis peaks in 2. The synthesis and characterization of two magnesium porphyrins [Mg(TDMPP)(H 2 O) 2 ], 1 and [Mg(TDMPP)(pyz) 2 ], 2 where TDMPP = 5,10,15,20-tetrakis(3,5-dimethoxyphenyl)porphyrin and pyz = pyrazine have been described. The compound 1 in the presence of pyrazine forms hexa-coordinated compound [Mg(TDMPP)(pyz) 2 ], 2. Both compounds were structurally characterized. Theoretical calculations like structure optimization, calculation of energy of molecular orbitals and simulation of electronic spectra were performed. The HOMO-LUMO energy difference in compound 2 (2.53 eV) is slightly lower than in compound 1 (2.56 eV) which supports the redshift of UV–Vis peaks on binding pyrazine to compound 1. [Display omitted] [ABSTRACT FROM AUTHOR]

• New azo-azomethine dyes and their metal chelates that are predicted to be biologically active have been synthesized and characterized. • Single crystals suitable for X-ray diffraction studies were obtained for the synthesized azo-azomethine ligands. • UV–visible data showed that ligand showed polarity dependant tautomerism. • The new azo-azomethine compounds exhibited higher cytotoxic properties than 5-Fu on Hela cell lines. In this work, azo chromophore group (-N=N-) containing azomethine ligands 2-{(E)-[(2- chlorophenyl) imino ]methyl}-6‑methoxy-4-[(E)- phenyldiazenyl ]phenol (HL1), 2-{(E)-[(4- chlorophenyl) imino ]methyl}-6‑methoxy-4-[(E)- phenyldiazenyl ]phenol (HL2) and their Ni(II) and Cu(II) chelates (3–6) were prepared and characterized by the analytical and spectroscopic methods. Single crystals suitable for X-ray diffraction studies were obtained for the prepared azo-azomethine ligands. In the structures of these ligands, there is an intramolecular phenol-imine hydrogen bond (O1-H·····N1) with a distance of 2.580(3)Å. There are also weaker intermolecular hydrogen bond type interactions CH·····O and CH·····N=N stabilising the structures. The ligands behaved as bidentate, coordinating through the nitrogen atom of the azomethine group (CH=N) and the oxygen atom of α‑hydroxyl group (-OH). As a result of analytical and spectral analysis, the metal:ligand ratio was 1:2 in the synthesized copper(II) chelates, while the metal ligand ratio was 1:1 in the nickel(II) chelates. In nickel(II) chelates, one CH 3 COO− anion and one H 2 O molecule form a coordination bond with Ni(II) ion. The new bands in infrared spectra of the metal chelates in the region 522–504 cm−1 and 467–455 cm−1 are attributed to ν(M-O) and ν(M-N) vibrations, respectively. The effect of various solvents with different polarities on the UV–visible spectra of the azo-azomethine dyes was studied. Additionally, anti-cancer properties of the synthesized ligands and their metal chelates have also been investigated. The compounds showed relatively higher anticancer properties than 5-FU against HeLa cells. [Display omitted] [ABSTRACT FROM AUTHOR]

• We have synthesized amide-based macrocyclic complexes of Co(II). • The compounds were characterized by IR, Mass. UV–visible, 1H NMR, 13C NMR, TGA and XRD studies. • A distorted octahedral geometry has been assigned for Co(II) complexes. • DFT and molecular docking studies have been provided. • The positive findings of Antimicrobial, in vitro cytotoxic and antioxidant activity have been discussed. The novel cobalt (II) macrocyclic complexes [Co(N 4 O 4 MacL 1)Cl 2 ]-[Co(N 4 O 4 MacL 3)Cl 2 ] have been synthesized by using the macrocyclic ligands [N 4 O 4 MacL 1 ], [N 4 O 4 MacL 2 ] and [N 4 O 4 MacL 3 ] that have an N 4 O 4 core. To investigate Co(II), metal complexes [Co(N 4 O 4 MacL 1)Cl 2 ]-[Co(N 4 O 4 MacL 3)Cl 2 ] with new ligands, elemental analyses, infrared, magnetic measurements, UV–visible, 1H NMR, 13C NMR, and XRD studies were utilised. According to the spectrum data, the ligands perform as a mononegative tetradentate. Based on magnetic and electronic spectrum data, an octahedral structure for Co(II) metal complexes has been postulated. The Coats-Redfern and FWO techniques are used to determine the thermodynamic characteristics of ligands and their complexes. The molecular modelling using the DFT technique displays bond angles, bond lengths, and quantum chemical factors. To determine their ability to prevent the growth of harmful fungus and bacteria, the ligands [N 4 O 4 MacL 1 ]- [N 4 O 4 MacL 3 ] and their complexes were tested in vitro against A. Niger, C. albicans and B. subtilis, S. aureus, E. coli and S. typhi fungal and bacterial organisms, respectively. By using DPPH free radical scavenger assays, the in vitro antioxidant capabilities of each compound were evaluated. The [Co(N 4 O 4 MacL 3)Cl 2 ] antioxidative capabilities revealed significant radical scavenging power. All of the compounds under research were examined for cytotoxicity using the MTT assay on MCF-7 and HepG-2 cells, and the findings revealed that [Co(N 4 O 4 MacL 2)Cl 2 ] show outstanding cytotoxic activity against HepG-2 with IC 50 17.94 ± 045 at a concentration of 25 ppm. Additionally, docking investigations of the produced compounds were carried out in order to validate the biological outcomes. Considerably, the current Co (II) complexes with their effective antimicrobial, antioxidant, and cytotoxicity activity would be probably appraised for further medicinal and pharmaceutical applications. [Display omitted] [ABSTRACT FROM AUTHOR]

• Manuscript reports a new Schiff's base synthesized from sulfanilamide and ethyl-methyl ketone. • Highest dipole moment value observed in water solvent, when compare to gas phase and DMSO. • Lowest bond gap vale observed in water solvent. PES study reported with maximum energy is -1041.90885634 (Hartree). • Detailed vibrational spectral and potential energy distribution analysis reported. • The electronic spectra and MESP performed with gas phase and various solvent phase. The compound 4-(butan-2-ylideneamino)benzenesulfonamide (EMKNI) was subjected to spectroscopic investigations, both experimental and theoretical in nature. The research study was conducted at two distinct levels. The initial stage involved the acquisition of experimental data, including FT-IR, NMR (1H, 13C), absorption (UV) and fluorescence spectral data. The subsequent stage involved the execution of theoretical calculations (UV) at the TD-DFT/WB97XD/cc-pVDZ basis set. The vibrational analysis was done for each vibrational modes using potential energy vibrational analysis (PED). A comparison was made between the theoretical NMR and the corresponding experimental data. In NLO study the water solvent showed highest NLO property, due to solvent effect. The emission study was done and showed two different wavelengths. A TD-DFT was made between water, DMSO and gas phase and experimental absorption wavelengths (λ) made in DMSO solvent. Furthermore, the FMO and MEP study were made using the different solvents such as water, DMSO and gas phase. The topological analysis studies were done such as ELF, LOL and RDG. The docking study was done and identify the highest binding energy score. [Display omitted] [ABSTRACT FROM AUTHOR]

• Manuscript reports a new Schiff's base synthesized from sulfanilamide and ethyl-methyl ketone. • Highest dipole moment value observed in water solvent, when compare to gas phase and DMSO. • Lowest bond gap vale observed in water solvent. PES study reported with maximum energy is -1041.90885634 (Hartree). • Detailed vibrational spectral and potential energy distribution analysis reported. • The electronic spectra and MESP performed with gas phase and various solvent phase. The compound 4-(butan-2-ylideneamino)benzenesulfonamide (EMKNI) was subjected to spectroscopic investigations, both experimental and theoretical in nature. The research study was conducted at two distinct levels. The initial stage involved the acquisition of experimental data, including FT-IR, NMR (1H, 13C), absorption (UV) and fluorescence spectral data. The subsequent stage involved the execution of theoretical calculations (UV) at the TD-DFT/WB97XD/cc-pVDZ basis set. The vibrational analysis was done for each vibrational modes using potential energy vibrational analysis (PED). A comparison was made between the theoretical NMR and the corresponding experimental data. In NLO study the water solvent showed highest NLO property, due to solvent effect. The emission study was done and showed two different wavelengths. A TD-DFT was made between water, DMSO and gas phase and experimental absorption wavelengths (λ) made in DMSO solvent. Furthermore, the FMO and MEP study were made using the different solvents such as water, DMSO and gas phase. The topological analysis studies were done such as ELF, LOL and RDG. The docking study was done and identify the highest binding energy score. [Display omitted] [ABSTRACT FROM AUTHOR]

• A new crystalline salt betainium triiodide, (BetH)(I 3) has been prepared. • Crystal structure, IR, UV–Vis spectra and electronic structure were studied. • An (A +··· A +) type centrosymmetric di-cation was found in the structure of (BetH)(I 3). • Bandgaps calculated for direct and indirect transitions are 1.657 eV and 1.642 eV, respectively. • Bandgap measured using diffuse reflectance spectrum is 1.66 eV. A new salt of betaine, betainium triiodide, (BetH)(I 3), was synthesized and characterized using structural analysis and infrared spectroscopy. It crystallizes in the monoclinic space group C 2/ m with the asymmetric part containing half of the formula unit. The structure determination revealed that the betainium cation forms an (A +··· A +) type centrosymmetric betainium···betainium dimeric cation with an O···O distance of 2.662(6) Å. The presence of the triiodide anion in the structure provides semiconductor properties of the resulting crystal. The bandgap for (BetH)(I 3) was calculated from the electronic structure based on the crystal structure and measured from the diffuse reflectance spectrum. The results are compared with two previously known structurally characterized salts of amino acids that also contain the triiodide anion: (l -AlaH··· l -Ala)(I 3) and (GlyH)(I 3). Thermal properties of the crystal were studied by TG and DSC methods. Iodide and iodine arrangement in the structure of (BetH)(I3) [Display omitted] [ABSTRACT FROM AUTHOR]

• Synthesis of a series of methoxy iron(III) isoporphyrins of tetraphenylporphyrin derivatives using the chemical oxidant ceric ammonium nitrate. • Characterization of Fe(III) isoporphyrins using UV–Visible, IR, ESI-Mass, elemental analysis, thermal gravimetric studies (TGA) and powder X-ray diffraction studies. • Theoretical studies like optimization of geometry, simulation of optical spectra, and energy calculations of Fe(III) isoporphyrins using the DFT method. • Electrochemical studies were performed for iron(III) isoporphyrins for the first time. Detailed studies on iron(III) isoporphyrins, which are isoelectronic with iron(IV)-oxo porphyrin radical and very much reactive in nature are rare in the literature. Therefore, here we have reported the synthesis of a series of methoxy iron(III) isoporphyrins of tetraphenylporphyrin derivatives using chemical oxidants and characterized well with UV–Visible, IR, ESI-Mass, elemental analysis, thermal gravimetric studies (TGA), Powder X-Ray Diffraction studies and 1H NMR spectroscopy. The electrochemical studies were performed for the first time on such type iron(III) isoporphyrins. ESR and magnetic susceptibility studies supported the high-spin iron(III) nature of the isoporphyrins. For the first time, theoretical studies like geometry optimization, simulation of optical spectra, and energy calculations were performed on a methoxy isoporphyrin of simple [FeIII(TPP)Cl] (Iron(III) tetraphenyl porphyrin) using the density functional theory method to understand the typical electronic, redox and highly reactive nature of iron isoporphyrins. The theoretical calculations supported the strong absorptions at the near-IR region in electronic spectra, very reactive nature and typical redox behavior of iron(III) isoporphyrins. [Display omitted] [ABSTRACT FROM AUTHOR]

• Four Ni(II) complexes were prepared from benzil-bis(thiosemicarbazones) ligands. • The starting materials and conditions influence the type of isomer formed. • Both symmetric and asymmetric isomers were determined by single-crystal XRD. • DFT was used to examine the electronic transitions and thermodynamic parameters. • A kinetic study was achieved in order to comprehend the isomerization process. The formation of isomers can be stimulated by many factors and their properties are often used in the development of new catalysts, optical devices and drugs. Herein, reactions between benzyl-bis(thiosemicarbazones) ligands, so called H 2 LR (R = Me or Et), were investigated with different NiII starting materials and conditions, affording solids with divergent colors. They were characterized by elemental analysis, FTIR, UV–Vis and 1H NMR spectroscopies, as well as cyclic voltammetry, which revealed distinct products from the respective NiII starting precursors. However, the ESI(+)-MS the products of each ligand presented almost identical m/z patterns, independently from their precursors. Remarkably, the structures of both products were determined by single-crystal X-ray diffraction, showing the formation of two isomers of the type NiIIN 2 S 2 , coordinated symmetrically (5–5–5 membered chelate rings) when NiCl 2 ·6H 2 O or Ni(Ac) 2 ·4H 2 O were used as precursors or asymmetrically (4–6–5 membered chelate rings) upon reaction with [Ni(acac) 2 ]. Theoretical calculations by DFT were also accomplished to explain the electronic spectra of the two products and to calculate the thermodynamic parameters related to the stability of the two isomers. Finally, a kinetic study was performed to investigate the formation of the asymmetrical and the symmetrical complexes. [Display omitted] [ABSTRACT FROM AUTHOR]

• The Co(II) Schiff base complex was synthesized using microwave assisted process. • The molecular formula and geometry of the Co(II) Schiff base complex was studied. • Spectroscopic and thermal characterization of synthesized complex was studied. • Antibacterial and antifungal activity of the complex was studied. The study comprehensively focusses on the synthesis and characterization of a novel Co(II) metal complex formed by the condensation of phenylacetyl urea and salicylaldehyde with Thiocyanate ion using an eco-friendly microwave irradiation technique, which resulted in a higher yield. The molecular formula and geometry of the complex were deduced through an array of techniques including UV–Vis spectra, FT-IR, Far IR, Cyclic voltammetry, thermal analysis, and Powder XRD. The molar conductance data revealed a non-electrolyte [1:0] type complex. Notably, the FT – IR spectral peaks obtained at 3388 cm−1, 2914 cm−1,1622 cm−1 shows that Schiff base and Thiocyanate ions were coordinated to the metal ion in a monodentate manner. Furthermore, electronic spectra values confirmed a pseudo tetrahedral geometry for the complex. Intriguingly, our study also encompassed an exploration of the biological activities of both the Schiff base ligand and the Co(II) metal complex. By subjecting them to antimicrobial assays against various microorganisms, including Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeurginosa, Staphlococcus aureus, Bacillus cereus, Aspergillus favus, Aspergillus niger, Aspergillus sojae, Aspergillus oryzae, and Candida albicans. It was found that the complex exhibited moderate activity against bacteria and remarkably enhanced activity against fungi when compared to the free Schiff base ligand. Additionally, we investigated the DPPH free radical scavenging activity of the complex and the ligand, unveiling that the Co(II) complex demonstrated significantly higher antioxidant activity in comparison to the ligand. These results highlight the potential of the synthesized Co(II) complex as a promising candidate for biomedical applications. Overall, this study not only sheds light on the synthesis and characterization of the Co(II) metal complex with a novel Schiff base ligand but also unravels its distinct biological activities, indicating its potential significance in antimicrobial and antioxidant applications. [ABSTRACT FROM AUTHOR]