Azomethine Nitrogen Research Articles

Unexpected stability of the iron(II) complex by an asymmetrical Schiff base from Fe(III): structure, magnetic and Mössbauer investigations.

The asymmetric Schiff base prepared in situ from ethylenediamine and pyridine-2-carboxaldehyde reacts with Fe(ClO4)3·6H2O to form the Fe(II) complex [FeL2](ClO4)2 with L = N,N-diethyl-N'-(pyridin-2-yl)methylene)ethane-1,2-diamine, where the Fe(III) starting material has been unexpectedly reduced to Fe(II). This complex was characterized by elemental analysis, infrared spectra, single crystal and powder X-ray diffraction measurements, variable temperature DC magnetic measurement and room temperature Mössbauer spectroscopy. The asymmetric ligand L coordinates in a tridentate fashion through its pyridyl, azomethine and amino nitrogen atoms, generating a distorted octahedral geometry around the central metal ion. Variable temperature magnetic studies and a Mössbauer measurement show that the iron is locked in the low spin Fe(II) states.

STUDIES ON THE COMPLEXES OF ISONICOTINOYL 2-CHLOROBENZALDEHYDE HYDRAZONES WITH CU II AND MN II AND THEIR ANTIMICROBIAL STUDIES

Complexes isonicotinoyl 2-chlorobenzaldehyde hydrazone with Mn II and Cu II were synthesized and characterized using UV visible spectrophotometry, Infrared spectrophotometry Atomic Absorption Spectrophotometry, melting point, solubility test, conductivity measurement, magnetic susceptibility. Some bacterial and fungal strains were used to screen for the biological activities of the ligands and complexes. The melting point of the ligand (216 – 218) °C is higher than 106 – 107.80C of the Mn complex. The Cu complex decomposed at 174°C.The solubility showed that the ligand and complexes were soluble in dimethyl sulphoxide, but insoluble in water. The conductivity test showed that the Cu complex are conductors with higher value (9.934) µS/cm, while the Mn complexes are non-conductor with lower value (1.346) µS/cm. The magnetic susceptibility measurement pointed out that the complexes are paramagnetic with unpaired electrons. There was coordination via the azomethine nitrogen and carbonyl oxygen in all the complexes with a square planar geometries stoichiometrically combined in the ratio of ML 1:2 for the metal and ligand respectively. The ligand and complexes showed appreciable activities against Methicillin resistant staphlococus aureus (MRSA), Escherichia coli, Helicobacter pylori, salmonella typhi Aspergillus fumigatus and aspergillus niger

Synthesis, Characterization and Catalytic/Antimicrobial Activities of Some Transition Metal Complexes Derived from 2-Floro-N-((2-Hydroxyphenyl)Methylene)Benzohydrazide.

In the last few decades, the field of coordination chemistry has grown very fast, especially in the fields of pharmaceutical, biological and catalytic studies. In ancient times, metals were thought to be beneficial to health issues but nowadays the link between organic-metal substances and different industrial and medicinal properties is well established. A Schiff base ligand (2-fluoro-N'-[(E)-2-hydroxyphenyl) methylene] benzohydrazide) was reacted with a series of transition metals to produce complexes with a general formula [ML2(NO3)]NO3.nH2O, where [M = Zn, Cu, Co, Ni, Mn], and [n = 0, 1], corresponding to complexes 1-5. The nature of the bond was determined in the solid state and solution using spectral studies (1H-NMR, 13C-NMR, UV-Vis and FT-IR), TGA, EPR, elemental analysis and molar conductivity measurement. All M(II) complexes are 1:1 electrolytes, as illustrated by their molar conductivities. The results demonstrate that all synthesized complexes present a coordination number of six by the bonding of the bidentate ligand via its azomethine nitrogen atoms and carbonyl oxygen atoms, as well as with one nitrate group as a bidentate ligand via two oxygen atoms. The DPPH radical scavenging technique was used to investigate the antioxidant activities of the ligand [L] and the metal complexes. It is clear that the activity increased in M (II) complexes compared to the Schiff base ligand. Complex 5 showed the highest activity, with an excellent activity of 90.4%, while complex 4 showed the lowest. The antibacterial activities of the Schiff base and its complexes have been examined against various pathogenic bacteria to measure their inhibition potential. Complex 2 showed remarkable activity against Gram (+) bacteria and fungi with an MIC value of 8 μg/mL, which is greater than that of the positive controls, oxytetracycline and fluconazole. The catalytic activities of all complexes were examined in the oxidation of aniline, and the results illustrated that all complexes had a 100% selectivity in producing only azobenzene, and complex 4 had the highest activity (91%). The obtained results from this study show that the antioxidant and antibacterial properties of both the Schiff base ligand and its derived complexes are promising, with some demonstrating remarkable activities. Moreover, the catalytic activities and selectivities of the prepared complexes in aniline oxidation are interesting.

Synthesis, Characterization, Biological, and Antioxidant Activity of New Metal Ion Complexes with Schiff Base Derived from 2-Hydroxybenzohydrazide

The study involved the synthesis of new complexes with tetradentate ligand (LH). The general formula of complexes was [M(LH)(H2O)2] with M of Ni2+, Co2+, Cu2+, and Zn+. The ligand was synthesized by treating the 2-hydroxybenzohydrazide with salicylaldehyde. The structural characteristics of ligands and complexes were analyzed using various techniques, including elemental analyses, magnetic susceptibility, molar conductivity, infrared, ultraviolet absorption, mass, and NMR spectroscopy studies. The physical measurements indicated that the prepared complexes are non-electrolyte and showed that the ligand is tetradentate when coordinated with metal ions through the nitrogen of azomethine (–C=N–), two oxygen atoms of O–H phenolic, and an oxygen atom of carbonyl (C=O) for benzohydrazide. It was found that Co2+, Cu2+, and Zn2+ complexes are octahedral, while Ni2+ complexes are square planar. The biological screening of the complexes demonstrates that the Schiff base metal complexes exhibit remarkable efficacy in combating microorganisms by utilizing Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli) bacteria, as well as Candida albicans fungi. Hence, their results were good in inhibition. Then, the potential of these prepared compounds as antioxidants was determined by inhibiting free radicals.

Homoleptic and Heteroleptic Coordination Environment of Palladium Molecular Catalysts for Oxygen Reduction to Hydrogen Peroxide

Hydrogen peroxide (H2O2) serves a wide range of purposes in industries such as chemical manufacturing, energy production, and wastewater treatment, either alone or in combination with other oxidizers. The demand for H2O2 has seen a notable increase due to its heightened use in disinfection amid the COVID-19 pandemic. Currently, industrial synthesis of H2O2 relies on anthraquinone technology, a complex process involving multiple steps including the use of H2 gas, transfer of H2O2 between solvents, distillation of concentrated H2O2, and potentially hazardous transportation. Thus, advancements in developing efficient and selective electrocatalysts for the two-electron oxygen reduction reaction (2e- ORR) are crucial for promoting the adoption of electrochemical synthesis of H2O2 production. In our study, we synthesized single-atom electrocatalysts—Pd-N4-CO, Pd-S4-NCO, and Pd-N2O2-C through an in-situ synthesis approach involving heteroatom-rich ligands and activated carbon under mild reaction conditions. These catalysts feature both homoleptic (Pd-N, Pd-S) and heteroleptic (Pd-NO) coordination spheres, which are expected to demonstrate selectivity in the two-electron/four-electron pathway of the oxygen reduction rection (ORR). Moreover, the coordination of the Schiff base and poly pyridyl ligands to the palladium atom could be observed via the thiol ligand (Pd-S4-NCO), azomethine nitrogen and hydroxyl oxygen atoms (Pd-N2O2-C), and the pyridinic nitrogen atom of 1,10-phenathroline-5,6-dione (Pd-N4-CO). Notably, Pd-N4-CO shows promise as an electrocatalyst for two-electron ORR, facilitating green H2O2 production with high activity and selectivity in a basic electrolyte, exhibiting minimal onset overpotential and over 95% selectivity across various potentials. The electrocatalysts performance in ORR follows Pd-N4-CO > Pd-N2O2-C > Pd-S4-NCO, aligning with the Pull-Push mechanism. This mechanism underscores the significance of strong coordination of Pd with electronegative donor atoms like N and O, and weak coordination with intermediate *OOH, enhancing selectivity and green H2O2 production. Our findings, both experimental and DFT calculations, offer new insights into engineering heteroatom-rich ligands to tune the electronic structure of catalytic active sites. This understanding informs the atomic-level structure-activity and selectivity relationship, facilitating the development of more effective and efficient catalysts for the electrochemical synthesis of hydrogen peroxide.

Experimental and computational investigations of new organotin(IV) complexes derived from hydrazone ligands: Synthesis, structural analysis and biological assessment

In this article, we have presented the synthesis, structural analysis, and biological assessments of twelve new diorganotin(IV) complexes (derived from heterocyclic hydrazone ligands through condensation reaction between 9-formyl-8-hydroxyjulolidine and aromatic hydrazide derivatives) to discover potent biological agents. The synthesized compounds have been thoroughly characterized using numerous spectroscopic and physicochemical methods, including (1H, 13C and 119Sn) NMR, FT-IR, mass spectrometry, powder XRD and SEM. These scrutinizes indicate that complexes exhibited a pentacoordinated geometry, coordinating through azomethine nitrogen atom, enolic oxygen atom, phenolic oxygen atom and carbon atoms of alkyl/aryl groups of organotin derivatives. DFT (Density functional theory) studies were conducted at the B3LYP/LanL2DZ/6-311G level of hypothesis to investigate the quantum chemical aspects of specified compounds. These properties were facilitated through analyses of charge distribution and molecular orbitals. The antioxidant effectiveness of the prepared compounds was examined employing the DPPH assay and the results revealed that complex 7 exhibited strong antioxidant potential, having an IC50 value of 2.3 µM. Moreover, the prepared compounds were assessed for their effectiveness against four bacterial (B. cereus, B. subtilis, P. aeruginosa, E. coli) as well as two fungal strains (C. albicans and A. niger) using serial dilution approach. Complexes 7, 11, 14 and 15 having MIC values ranging from 0.0051-0.0048 µmol/mL have highest antimicrobial potency equivalent to reference drugs, Fluconazole (MIC = 0.0051 µmol/mL) and Ciprofloxacin (MIC = 0.0048 µmol/mL).

Experimental and computational insights into antibacterial and antioxidant properties of metal complexes with isoniazid-based Schiff base ligands

Isoniazid-based Schiff base ligands coordinate with transition metals through azomethine nitrogen and oxygen donors, enhancing electron delocalization and influencing redox properties. This structural modification impacts antibacterial and antioxidant behaviors by modulating metal-centered redox reactions, with geometry and oxidation states playing critical roles. Schiff base metal complexes derived from isoniazid and benzaldehyde were synthesized with Cu(II), Ni(II), and Co(II) ions and characterized using UV-Vis, FT-IR, NMR, and DFT analyses.The Cu(II) complex (CuL) exhibited the highest antibacterial activity, showing a 13.83±0.44 mm inhibition zone against Staphylococcus aureus. Antioxidant activity, assessed via DPPH radical scavenging, revealed CuL as the most effective, with an IC50 of 194 µg/mL. Molecular docking studies with the MurA protein (PDB ID: 3KR6) highlighted NiL's strong binding affinity (binding energy: -10.5 kcal/mol), suggesting therapeutic potential. Frontier molecular orbital (FMO) analysis indicated lower energy gaps for CuL, NiL, and CoL, correlating with higher biological activity. These findings underscore the potential of these metal complexes as agents for combating bacterial infections and oxidative stress.

Synthesis, And Characterization Of Five New Metal Transition Complexes Derived From The Schiff Base Ligand N' 1 ,N' 4 -Bis(2- Hydroxybenzylidene)Succinohydrazide (H4L)

Schiff base ligand N'1 ,N'4 -bis(2-hydroxybenzylidene)succinohydrazide (H4L) was synthesized via condensation of salicylaldehyde and succinohydrazide in ethanol. The complexes were obtained from 1:2:1 (H4L/LiOH/MCl2 .nH2O) molar ratio reactions, yielding compound formulated as [M2(H2L)2] .nH2O, where M=Mn(II, Fe(II), Co(II), Ni(II) and Cu(II). Elemental analysis, 1H and 13C NMR, FT-IR and UV-Visible spectroscopies were used for the characterization of the ligand. The complexes were structurally studied using FT-IR, UV-Visible spectroscopies, conductance, and magnetic susceptibility measurements. All complexes are non-electrolytes in DMF solutions. In each complex unit two ligand molecules acting in hexadentate fashion bridges two metal ions are present. Thus, each metal ion of the binuclear unit is coordinated to two azomethine nitrogen atoms, two phenolate oxygen atoms and two carbonyl oxygen atoms, resulting in a hexacoordinated metal ion. The environment around each metal ion is described as octahedral geometry owing to the results of the magnetic susceptibility measurement and the UV-visible spectra analyses.

Synthesis, Structure And Thermogravimetric Analysis Of Copper(II) Complex Derived From N1 ,N3 -Bis(1-(Pyridin2-Yl)Ethylidene)Propane-1,3-Diamine

Cu(II) complex derived from ligand, (N 1 ,N3 -bis(1-(pyridin-2-yl)ethylidene)propane-1,3-diamine (L) which was synthetized in situ, is reported. The isolated Cu(II) complex was characterized by elemental analyses, IR, and UV-Vis spectroscopies, and Thermogravimetric analyze (TGA). Additionally, the structure of the complex was determined by single crystal X-ray diffraction study. The diimine ligand was coordinated to Cu(II) ion through two azomethine nitrogen atoms and two pyridine nitrogen atom. One bromide ion complete the coordination sphere yielding a distorted square pyramidal geometry. The structure of the copper(II) complex is confirmed by X-ray diffraction. The complex crystallizes in the monoclinic space group P21/c with unit cell dimensions a = 8.3433 (3) Å, b = 13.2605 (3) Å, c = 18.838 (6) Å,  = 97.522 (16)°, V = 2066.2 (6) Å3 , Z = 4, R1 = 0.048 and wR2 = 0.081. The Cu(II)cation in N4Br inner is situated in a distorted square pyramidal environment. Thermogravimetric analyze of the complex were carried out at 20–800 °C and showed that the complex were decomposed into three steps.

Copper(II) complexes containing hydrazone and bipyridine/phenanthroline ligands for anticancer application against breast cancer cells

In this work, mixed ligand Cu(II) complexes containing hydrazone and bipyridine ligands (CB1-CB5), or hydrazone and phenanthroline ligands (CP1-CP5) have been synthesized and characterized by spectroscopic and analytical techniques. Single crystal X-ray structure of complex CB1 revealed that two nitrogen atoms from bipyridine, one carbonyl oxygen, one azomethine nitrogen and one hydroxyl oxygen from the hydrazone ligand coordinated to Cu(II) ion, adopting a distorted square pyramidal geometry. Interaction of these complexes with calf thymus (CT) DNA and bovine serum albumin (BSA) was analyzed by absorption and emission studies. Further, the in vitro anticancer activity of the complexes was investigated exclusively against the breast cancer cells namely MCF7, T47D and MDA MB 231, and a normal breast MCF 10a cell line. The phenanthroline bearing complexes (CP1-CP5) displayed better activity than their bipyridine counterparts as seen from the IC50 values. In addition, the most active complex CP1 having an IC50 value of 5.8 ± 0.3 μM against T47D cancer cells was investigated for its mode of cell death through acridine orange/ethidium bromide(AO/EB), 4′,6-diamidino-2-phenylindole (DAPI) and Annexin-V fluorescein isothiocyanate (FITC) staining assays which revealed apoptosis. Lastly, the cell cycle analysis revealed that complex CP1 induced cell death in T47D cancer cells at the G0/G1 phase.

Two new cyclobutane derivatives of thiazolidin-4-ones: Synthesis, spectroscopic characterization, DFT quantum chemical calculations and determination of protonation constants

In the first stage of this study, 2-((4-(4-(3-methyl-3-phenylcyclobutyl)thiazol-2-yl)imino)thiazolidin-4-one (compound 1) and 2-((4-(3-(2,5-dimethylphenyl)-3-methylcyclobutyl)thiazol-2-yl)imino)thiazolidin-4-one (compound 2) were synthesized, characterized using FT-IR and NMR methods, and a combination of experimental and theoretical studies of the title compounds was performed. With the aid of the 6–311+G(d,p) basis set, all theoretical computations were performed using the density functional theory (DFT) B3LYP approach. The GIAO approximation was used to compute the chemical shifts of 1H and 13C NMR. Theoretical calculations provide detailed information on chemical activity and molecular properties by determining electrophilic and nucleophilic properties. Accordingly, global chemical activity descriptors (FMOs, hardness, and softness parameters) were investigated, natural bond orbital (NBO) analyses were performed, thermodynamic properties at different temperatures were calculated, and the related relationships with temperature were obtained. The experimental and calculated NMR data presented consistent results for both compounds. R2 values for the 1H NMR and 13C NMR of compound 1 are 0.9914 and 0.9988, respectively. For the second compound, 2, these values are 0.9957 and 0.9962, respectively.In the second stage, the acid-base equilibria of title compounds containing cyclobutane, thiazole, and thiazolidinone functional groups were investigated potentiometrically in 60 % dioxane-water media at room temperature and constant ionic strength. The values of the protonation constants determined in this study, logKNH(1) and logKNH(2), are related to the protonation of the azomethine nitrogen atom and the nitrogen atom on the thiazole ring, respectively. The sum of these values is the total protonation value of title compounds. The total protonation constants for compounds 1 and 2 are 10.59 and 10.58, respectively.

Diorganotin(IV) derivatives of salicylaldehyde hydrazones: Synthesis, structural characterization, crystal structure of dimethyltin(IV) complexes, and CT-DNA binding

Six new diorganotin(IV) complexes of H2L1 and H2L2 (Me2SnL1, n-Bu2SnL1, Ph2SnL1, Me2SnL2, n-Bu2SnL2, and Ph2SnL2) and six recently reported diorganotin(IV) complexes of H2L3 and H2L4 (Me2SnL3, n-Bu2SnL3, Ph2SnL3, Me2SnL4, n-Bu2SnL4, and Ph2SnL4) have been synthesized and characterized by CHN analyses, FT-IR, multinuclear NMR including 1H, 13C and 119Sn, ESI-MS and single crystal X-ray diffraction studies. Hydrazones (H2L1–4) are derived from the condensation of indole-2-acetic hydrazide and salicylaldehyde (H2L1)/4-methoxysalicylaldehyde (H2L2)/5-chlorosalicylaldehyde (H2L3)/5-bromosalicylaldehyde (H2L4). Single-crystal X-ray (Sc-X-ray) diffraction studies of Me2SnL1 (1) and Me2SnL4 (10) confirm the di-anionic and tridentate (ONO) behaviour of hydrazones, which may bind with organotin(IV) moiety via enolic oxygen, phenolic oxygen, and azomethine nitrogen. Further, Sc-X-ray diffraction studies suggested that the complexes have distorted square-pyramidal geometry. The groove binding or electrostatic interactions of H2L1–4 and R2SnL1–4 (1–12) with CT-DNA have been validated by investigating UV–Vis, fluorescence, and circular dichroism (CD) spectral titrations which revealed that H2L1–4 and R2SnL1–4 (1–12) have binding constants with CT-DNA in the range ∼105 M−1.

Synthesis, Characterization and Identification of Mononuclear Transition Metals Complexes 1, 3-Bis-((5-methyl-1H-Imidazol-4-yl) Methyleneamino) Propan-2-ol Ligand

The ligand 1,3-bis-((5-methyl-1H-imidazol-4-yl)methyleneamino)propan-2-ol (H3L) derived from 1,3-diaminopropan-2-ol and 5-methyl-1H-imidazole-4-carbaldehyde has been synthetized and used to prepare five complexes in which the ligand acts in tetradentate fashion. Complexes formulated as [Mn(H3L)(H2O)2].2SCN (1), [(Co(H3L)].2SCN (2), [(Ni(H3L)].2SCN (3), [(Cu(H3L)(NO3)].(NO3).2H2O (4), and [(Zn(H3L)].2SCN (5) were synthesized by mixing an equimolar amount of an methanol solution containing the appropriate nitrate salt and KSCN, in 1:2 ratio, in the case of 1, 2, 3 and 5 and an ethanol solution containing the appropriate ligand H3L. The complex 4 has been synthetized in the absence of KSCN. In all the complexes the ligand acts in its neutral form and in tetradentate fashion, its hydroxy group remaining free and non-deprotonated. The ligand is coordinated to metal ion through two azomethine nitrogen atoms and two pyrazole sp2 nitrogen atoms. The complexes are characterized by elemental analysis, conductance and room temperature magnetic moments measurements, UV–Vis and IR spectroscopic studies. The structure of the copper(II) complex 4 is confirmed by X-ray diffraction. 4 crystallizes in the monoclinic space group P21/c with unit cell dimensions a = 8.5459 (3) Å, b = 10.9177 (3) Å, c = 22.4562 (6) Å, b = 96.954 (3)°, V = 2079.79 (11) Å3, Z = 4, R1 = 0.050 and wR2 = 0.131. The CuII cation in N4O inner is situated in a distorted square pyramidal environment.

Synthesis, Characterization and In-vitro Antibacterial Activity Studies of Oxovanadium (IV) Complexes of α-Amino Acid Schiff Bases and 1,10-Phenanthroline Ligands

Oxovanadium(IV) complexes of the type [VO(L)(phen)] (VO-1 to VO-5) have been synthesized and characterized by FTIR and UV-Vis spectra, molar conductance, melting points, and magnetic susceptibilities measurements, where L= N-salicylidene-β-alanine (sal-ala), N-salicylidene-glycine (sal-gly), N-salicylidene-DL-β-phenylalanine (sal-pheala), N-salicylidene-leucine (sal-leu), and N-salicylidene-DL-methionine (sal-met), and phen is 1,10-phenanthtroline. The infrared spectral data reveals that the tridentate nature of the amino acid-based Schiff base ligand and the coordination of the ligand through azomethine nitrogen, phenolic oxygen and carboxylate oxygen with vanadyl (VO2+) ion. All of these complexes were determined to be non-electrolyte in nature, according to conductivity measurements. The magnetic moment measurements have been attributed that these complexes are paramagnetic and have d1 configuration of vanadium (IV) ion. The antimicrobial activity of the synthesized complexes was evaluated against four pathogenic bacteria viz. Escherichia coli, Proteus vulgaris, Bacillus subtilis and Staphylococcus aureus.

Optical properties of transition metals complex films derived from hydrazone oxime for optoelectronic devices

Hydrazone incorporating oxime nucleus and its Ni2+, Mn2+, Zn2+ and UO22+ metallic chelates have been prepared and completely characterized by different spectral, theoretical, and analytical techniques including NMR, FT-IR, mass, and EAS spectroscopy. The finding denoted that the Hydrazone ligand bonded as a dibasic tridentate chelator via deprotonated oximato nitrogen, enol carbonyl oxygen and hydrazono azomethine nitrogen atoms resultant in octahedral geometry for Ni2+, Mn2+, Zn2+ and UO22+. Theoretical studies by DFT/B3LYP/LANLDZ together with dipole moment, geometrical optimization, energetic parameters, and energy gap (HOMO–LUMO) were employed to support the geometrical structure of the synthetics. Additionally, these complexes were prepared in the form of thin film onto cleaned glass substrate by spin-coating technique. The values of the optical band gap (Eg) and film index of refraction (n) have been determined by many different methods. It was found that the hydrazone-oxime (OBBH2) film has the highest value of Eg (eV) where the UOBB complex film has the smallest value of Eg (2.56 eV). The latter is very close to the Eg value of ZnSe (2.58 eV). The refractive index changes with wavelengths show normal dispersion which is well discussed in terms of Sellmeier's dispersion model. Also, the nonlinear optical parameters viz. the first (χ(1)) and third (χ(3)) orders of nonlinear optical susceptibilities and the non-linear index of refraction (n2) have been studied. The complex dielectric constant (ε⌣=εr+iεi)), conductivity (σ⌣=σr+iσi), sheet resistance (Rs), and thermal have been investigated over the whole spectral range. According to the results of χ(1), χ(3) and n2 the complex films under study are candidates to be used in optical switching gadgets, optical modulators, and optical signal processing.

Synthesis, DFT calculation, molecular docking and in vitro anticancer activities of sulphanilamide incorporated Schiff base metal complexes

Transition metal complexes of the type [M(L2)Cl2] (M= Co, Cu, Ni and Zn) were synthesized from Sulphanilamide based novel Schiff base ligand (4-[(oxo-1,2-diphenylethylidene)amino]-benzene-1-sulphonamide) utilizing micro-wave helped blending and characterized by expository and spectroscopic strategies. Based on the findings of the NMR and FT-IR spectroscopy, it was determined that the azomethine nitrogen and oxygen atoms from the ligand are coordinated with the metal ions that correspond to them. The physicochemical properties, drug-like nature and pharmacokinetic properties were predicted by the SwissADME Online webserver. The compound's geometry, electrostatic potential, frontier molecular orbital and quantum chemical descriptors were determined. The most appropriate drug targets were identified by using a polypharmacology approach. To evaluate the ligand and its metal complexes' interactions with the chosen breast cancer targets, molecular docking was used. The findings demonstrated that the metal complexes had good interaction profiles and binding energies. Examining the compounds' in vitro anticancer potential, the results revealed that the biological ability of each molecule to prevent breast cancer varied. In light of this, each of the compounds that were synthesized has the potential to be utilized as possible candidates for breast cancer treatment.

Novel Cu(II) and Zn(II) Nanocomplexes Based on 5,6‐Diphenyl‐1,2,4‐Triazine: Preparation, Spectroscopic, TD‐DFT Calculations, Molecular Docking and Solvatochromic Studies

ABSTRACTThe reaction between 2‐hydroxy‐1‐naphthaldehyde and 3‐hydrazino‐5,6‐diphenyl‐1,2,4‐triazine produced a novel hydrazone ligand (DTHMN), which reacted with Cu(II) and Zn(II) metal ion in molar ratio 1:1, giving octahedral Cu(II)‐DTHMN and tetrahedral Zn(II)‐DTHMN nanosized complexes. The structural geometries have been elucidated on the basis of elemental analysis, nuclear magnetic resonance, infrared, electronic, and electron spin resonance spectra, and magnetic and molar conductance measurements as well as x‐ray diffraction and thermal analysis. TEM analysis showed that Zn(II)‐DTHMN complex has nano‐rode morphology shape. On the other hand, Cu(II)‐DTHMN has sphere shape within nanodomain. The DTHMN ligand exhibits ONN chelating sites through N‐triazine ring, azomethine nitrogen, and deprotonated OH group, forming the mononuclear metal complexes. The synthesized compounds showed a distinct solvatochromic behavior in different polar solvents. A bathochromic alteration is observed when moving from less to high polar solvents, indicating strong solute–solvent interactions accompanied by intramolecular charge transfer (ICT). The ground and excited state dipole moments of these compounds were determined experimentally by solvatochromic shift method using Bilot–Kawski, Lippert–Mataga, Bakhshiev, and Kawski–Chamma–Viallet functions and a microscopic Reichardt's solvent polarity parameter (ETN). The dipole moment is increased significantly upon excitation referring to stabilizing the excited species includes n–π* transition by polarity of solvent. The experimental results are generally consistent with those values obtained by B3LYP/GENECP method at 6‐311G(d,p) basis set for C, H, N, and O atoms and SDD (Stuttgart/Dresden) basis set for the metal atoms. The compounds were tested for antimicrobial efficiency against Gram‐positive bacteria, Gram‐negative bacteria, and fungus strain. Finally, molecular docking was used to study the interactions between donors (the current compounds) and receptors FabH–CoA complex (PDB code: 1HNJ).

Synthesis, structural characterization and computational studies of half- sandwich Ru(II) (η6-p–cymene) TPA appended benzhydrazone complex

A ruthenium complex of the type Ru[η6(p–cymene)Cl(L)] where L = Triphenylamine (TPA) appended O^N bidendate benzhydrazone ligand was synthesized and characterized by various analytical and spectral [UV, FT-IR, NMR (1H and 13C) and HRMS] methods. The solid state molecular structure of the ruthenium complex was investigated with the aid of X-ray crystallography results with pseudo-octahedral geometry around the metal centre. FT-IR spectroscopy confirms the coordination via the azomethine nitrogen and imidolate oxygen. Density Functional theory (DFT) calculations have been used to analyse the composition of frontiers orbitals. The bonding interactions between the ligand and ruthenium complex fragments have been examined by EDA. The spin-allowed singlet transitions were calculated with the TD-DFT method. NBO analysis shows that the donation from ligand to metal has value of 136.64 kcal/mol and the back donation is equal to 109.61 kcal/mol. Hence the ligand is a σ-donor with weak π-acceptor properties. The DOS spectrum of both ligand and complex were plotted in terms of Mullikan population analysis were calculated using the GassSum program. Further, the relative contributions to the Hirshfeld surface area for the various close intermolecular contacts of ruthenium complex are investigated and H…H interactions plays an important role for the construction of the crystal structure of the ruthenium complex.

Synthesis, structural elucidation, and antibacterial activities of novel copper(II), cobalt(II), and nickel(II) complexes with a bidentate Schiff base ligand against pathogenic bacteria

Novel Schiff base metal complexes diaqua(4-chloro-2-{[(4-(dimethylamino)phenyl)methylene]amino}phenolato)M(II) ion, (M = copper/cobalt/nickel) have been synthesized using the ligand 4-chloro-2-((4-(dimethylamino)benzylidene)amino)phenol, which was prepared by reacting 2-amino-4-chlorophenol with 4-(dimethylamino)benzaldehyde in a molar ratio of 1:1. The synthesized compounds were characterized based on elemental analysis, FTIR, UV–vis., 1H and 13C NMR, powder XRD, mass spectrometry and magnetic studies. Spectroscopic investigations demonstrated that the metal atom coordinates to a bidentate Schiff base ligand via the azomethine nitrogen and phenolic oxygen. The appropriate molecular geometry for each metal complex has been proposed through the analysis of spectroscopic and analytical data, Specifically, tetrahedral geometry has been proposed for Co(II), Ni(II), and square planar geometry for Cu(II) complex. Theoretical calculations employing Density Functional Theory (DFT) validated the experimental results, elucidating optimized geometries, frontier molecular orbitals, natural bond orbital distributions, molecular electrostatic potentials, non-linear optical properties, IR vibrational modes, and UV absorbance profiles. Additionally, the compounds' biological efficacy was validated through molecular docking against receptors for Gram(+ve) bacteria, Bacillus subtilis (PDB ID: 5H67), Staphylococcus aureus (PDB ID: 3TY7) and Gram(-ve) bacteria, Escherichia coli (PDB ID: 3T88), Proteus vulgaris (PDB ID: 5I39). The outcome revealed that Co(II) complex exhibited highest binding energy with Escherichia coli and Bacillus subtilis while the ligand with Proteus vulgaris (5I39) and Staphylococcus aureus (3TY7). Further the study was extended to the MD Simulation in water for 100 ns to evaluate the binding affinities and its stabilities by analyzing the deviation, fluctuations, and intermolecular interactions. The research presented here showcase the potential of employing a Schiff base ligand and its Co(II) complex in the synthesis of novel, highly potent antibacterial agents to combat emerging diseases, which holds considerable importance in the field of pharmaceutical science—however, in-vitro studies are needed to validate the results.

Diorganotin(IV) derivatives of ONO tridentate Schiff bases: Synthesis, spectroscopic characterization, DFT studies, CT-DNA binding, and plasmid-DNA cleavage studies

Two Schiff bases 2-amino-N'-(5‑bromo-2-hydroxybenzylidene)-3-(4-hydroxyphenyl)propanehydrazide (H2L1) and 2-amino-N'-(5‑chloro-2-hydroxybenzylidene)-3-(4-hydroxyphenyl)propanehydrazide (H2L2) and their six diorganotin(IV) complexes (R = C4H9 (1, 4), CH3 (2, 5), and C8H17 (3, 6)) have been synthesized. Schiff bases (H2L1–2) and their R2SnL1–2 complexes (1–6) have been characterized by CHNS analysis, IR spectroscopy, 1H, 13C, 119Sn NMR, and ES-MS. Schiff bases (H2L1–2) act as a dianionic tridentate ligand coordinated to Sn through phenolic and enolic oxygen and azomethine nitrogen in R2SnL1–2 complexes (1–6). A density functional theory (DFT)-based quantum chemical calculation validated the structures of R2SnL1 (1–3) and R2SnL2 (4–6) at the B3LYP/6‐311G(df,pd)/Def2‐SVP(Sn) and B3LYP/6‐31G(d,p)/Def2‐SVP(Sn) levels of theory, respectively. At these levels of theories, comprehensive electronic structure calculations determined atomic charges at selected atoms. Additionally, a molecular electrostatic potential (MEP) map identified electrostatic potential-varying sites on the molecule's surface, and MEP maps used to identify regions where other molecules might interact or react with the molecules on them. Furthermore, a conceptual-DFT-based global reactivity descriptor determined the stability and reactivity behaviour of R2SnL1–2 complexes (1–6). H2L1–2 and R2SnL1–2 complexes (1–6) have binding constants in the range ∼105 M-1 with CT-DNA, as revealed by UV–visible and fluorescence spectral titrations. UV-visible, fluorescence spectroscopy, and CD studies suggested that H2L1–2 and their R2SnL1–2 complexes (1–6) interact with CT-DNA electrostatically or groove-bound. DNA cleavage studies reveal that H2L1–2 and their R2SnL1–2 complexes (1–6) have ability to cleave the plasmid-DNA from its supercoiled form (SC, I) to nicked form (NC, II). However, n-Bu2SnL2 (4) and n-Oct2SnL2 complex (6) have higher cleavage activity than Schiff bases and other R2SnL1–2 complexes (1–6).