Molar Magnetic Susceptibility Research Articles

Cu(II)-Ln(III) (Ln = Gd, Tb and Dy) complexes of an unsymmetrical N2O3 donor ligand: field induced SMM behaviour of Cu(II)-Tb(III) complexes.

Three new hetero-metallic CuII-LnIII complexes [(CuL)Gd(NO3)3(CH3OH)]n (1), [(CuL)Tb(NO3)3(H2O)]·[CuL] (2) and [(CuL)Dy(NO3)3(H2O)]·[CuL] (3) have been synthesized using a mono-nuclear Cu(II) complex, [CuL], of an unsymmetrically di-condensed N2O3 donor Schiff base ligand, N-(3-methoxysalicylidene)-N-(salicylidene)-1,2-ethylenediamine (H2L). Single crystal X-ray crystallography revealed that complex 1 is a nitrate bridged 1D chain of dinuclear Cu(II)-Gd(III) units whereas in 2 and 3, the dinuclear Cu(II)-Ln(III) units are co-crystallized with a [CuL] unit. The Ln(III) centers are nine coordinated with the geometry of a spherical capped square antiprism for Gd and spherical tricapped trigonal prism for Tb and Dy. The geometry of the Cu(II) center is distorted octahedral for complex 1 and distorted square planar for complexes 2 and 3. Temperature-dependent molar magnetic susceptibility measurements in 1-3 revealed the presence of overall ferromagnetic coupling between the Cu(II) and Ln(III) centers. Notably, field induced single-molecule magnet behavior was witnessed in the Tb(III) derivative (2). The ab initio calculations indicated that upon application of an external magnetic field, the tunneling in the ground state of complex 2 gets reduced and thereby field-induced SMM behaviour is observed. Besides, in the case of complex 1, BS-DFT calculations were carried out to gain further insights into the magnetic exchange coupling interactions between the Cu(II) and Gd(III) centers.

Utilizing Machine Learning Models for Predicting Diamagnetic Susceptibility of Organic Compounds.

This research is centered on examining the magnetic characteristics of organic molecules, with a particular emphasis on magnetic susceptibility, an essential physical property that provides insights into molecular microstructures and reaction processes. Traditional approaches for determining and calculating magnetic susceptibility are generally inefficient and demanding. To overcome these challenges, we have introduced a novel approach using quantitative structure-property relationships, which efficiently elucidates the relationship between the structural properties of molecules and their molar magnetic susceptibility. In our study, we utilized a comprehensive database comprising molar magnetic susceptibility data for 382 organic molecules. We applied six distinct molecular fingerprinting methods-RDKit Fingerprint, Morgan Fingerprint, MACCS Keys, atom pair fingerprint, Avalon Fingerprint, and topology fingerprint-as feature inputs for training seven different machine learning models, namely random forest, AdaBoost, gradient boosting, extra trees, elastic net, support vector machine, and multilayer perceptron (MLP). Our findings revealed that the integration of the atom pair fingerprint with the MLP model yielded R2 values of 0.88 and 0.90 in the validation and test sets, respectively, showcasing exceptional predictive accuracy. This advancement significantly expedites research and development processes related to the magnetic properties of organic molecules. Moreover, by employing this effective predictive method, it is expected to considerably reduce both experimental and computational expenses while maintaining high accuracy. This development represents a breakthrough in the rapid screening and prediction of properties for various compounds, offering a new and efficient pathway in this field of study.

Determining the chemical composition of diamagnetic mixed solids via measurements of their magnetic susceptibility

By exploiting the additive nature of the molar magnetic susceptibility χMol and molar mass mMol, the doping concentration δ of diamagnetic mixed solids can be resolved to ∼100 parts with only 20 mg of powdered samples. Eight examples are provided.

Anticancer and Antioxidant Activities of Biologically Active Newly Synthesized α-Amino Acid-Dithiocarbamate Complexes of Some Bivalent Metals

The present study focuses on the synthesis and characterization of L-proline dithiocarbamate and its L-prodtc metal(II) (M = Ni2+, Cu2+ and Se2+) complexes. The ligand was synthesized in the presence of an alkali through the reaction of one mole of carbon disulphide and L-proline in ethanol under ice cold condition. The solubility of this ligand in the media is attributed to its high hygroscopic character and therefore, its metal(II) complexes were synthesized using a freshly prepared ligand. The characterization of the metal(II) complexes were carried out by molar conductance, magnetic susceptibility, elemental analysis, TGA/DTA, mass, IR, Raman, UV-Visible, 1H and 13C NMR spectroscopic studies. The biological activity of all the metal(II) complexes has been examined using an inhibition method for bacteria and pathogenic fungus, which will assess their possible antibacterial, antioxidant, anticancer activities and anti-inflammatory. It has been observed that Se(L-Prodtc)2 exhibits anticancer activity against breast cancer cells (MCF7) and also observed that antioxidant activity of Se(L-Prodtc)2 is more as compared to standard BHT, whereas Cu(L-Prodtc)2 complex shows appreciable anti-inflammatory activity.

Structural, Characterization, Biological and Studying the Enzyme Activity of some transition metal complexes with 4- )(2- hydroxy phenyl imino) methyl) -2, 6-dimethoxy phenol

A new Schiff bases ligand 4- ((2-hyolroxy phenylimino) methyl) -2, 6-dimethoxyphenol derived from condensation of 2- amino phenol with 4-hydroxy -3, 5-dimethoxy benzaldehyde have been synthesized and characterized by spectroscopy, spectra, Mass spectrum and elemental microanalysis (C.H.N). Metal Complexes with ions have been also synthesized and characterized spectroscopic methods spectroscopy, flame atomic absorption, molar conductivity measurements and magnetic susceptibility. These studies indicate that the moler ratio for the complexes. The complexes showed characteristics octahedral geometry with the (O,N) ligand coordinated in bidentate mode while with showed square planer. The enzyme activity of the ligand and its metal complexes with esterase (AST) have also been studied . the study of enzyme activity indicates that the ligand its metal complexes revealed different inhibition behaviors. The synthesized ligands and their metal complexes have been tested against one type of fungi (candida albicans).

Design, Preparation some transition metal complexes of Chalcone-Azo with Paracetamol ligand and Evaluation anti-biological activity of some complexes

This search designed new series complexes of (Mn , Fe, Co, Ni, Cu, and Pd)(II) ,which prepared from Chalcone - Azo derived contained Paracetamol . The results illustrate that, the mole ratio (ligand : metal) (2:1) for all complexes and the geometric shapes of complexes were an Octahedral except Pd(II) complex was Square planer. the complexes characterized by ( UV-Visible, FTIR, C.H.N, Electrical molar conductivity and Magnetic susceptibility). This ligand coordinated with metal ions via (N) atom of Azo group and (O) atom of OH group of Paracetamol , the biological examination tested Pd(II)complex as antitumor Thyroid cancer cells(FTC-133) and compered it with healthy cells to evaluate the possibility of using it as therapeutic method. In addition , it tested Cu(II) and Ni(II) complexes as antimicrobial activity towards two types of Gram negative and Gram positive bacteria

Synthesis, Characterization, and Magnetic Properties of Iron(II) Complex with 2,6-Bis(pyrazol-3-yl)pyridine Ligand and Tetracyanonickelate Anion

The complex containing iron(II), 2,6-bis(pyrazol-3-yl)pyridine (3-bpp) as ligand, and tetracyanonickelate as counter anion has been synthesized and characterized. The characterization data suggest the corresponding formula of [Fe(3-bpp)2][Ni(CN)4]·4H2O. Meanwhile, the SEM–EDX analysis image confirms the existence of all elements contained in the complex except the hydrogen atom. The infrared spectra exhibit vibration bands of the functional groups of 3-bpp ligand and [Ni(CN)4]−1 anion. From magnetic property measurement, the complex's molar magnetic susceptibility (XMT) value is 2.65 emu mol−1 K at 300 K, which contains about 75% high-spin state of the Fe(II) complex. Upon lowering the temperature, the XMT value gradually decreases around 1.37 emu mol−1 K at 13 K. It decreases sharply to about 0.73 emu mol−1 K at 2 K. These values reveal that Fe(II) complex is in the low-spin (LS) state. As a result, the complex exhibited spin-crossover characteristics of gradual transition without thermal hysteresis, and the transition temperature occurred below room temperature with a transition temperature (T1/2) close to 140 K. The spin crossover property of the complex is supported by a thermochromic reversible color change from red-brown at room temperature to dark brown on cooling in liquid nitrogen associated with the high-spin to low-spin transition.

The slow magnetic relaxation in Dy-phthalocyanine single-molecule magnet induced by CH2Cl2 solvent molecules

DyPc2 and DyPc2•CH2Cl2 were prepared using the solvent thermal method. The x-ray diffractometer and the Fourier transform infrared spectrometer were used to explore the structure changes between DyPc2 and DyPc2•CH2Cl2. The results clearly demonstrate that the CH2Cl2 molecule can alter the crystal structures and, thus, change the molecular stacking structures of DyPc2 without destroying molecular integrity. Geometry optimization further proved that DyPc2 belongs to the space group P212121, while DyPc2•CH2Cl2 crystallizes in the space group Pnma. It is clearly demonstrated that the different molecular environment affects the structure of a single DyPc2 molecule to some extent, such as the twist angles of two Pc rings and the Pc−Dy−Pc angles. The molar magnetic susceptibility and hysteresis loops for DyPc2 and DyPc2•CH2Cl2 were also measured and compared. The negative Weiss constants were obtained by the Curie−Weiss law fitting above 50 K. The hysteresis loop for DyPc2•CH2Cl2 is wider than that of DyPc2, implying that the magnetic relaxation of DyPc2 slowed down, while quantum tunneling of the magnetization is prevented efficiently after absorbing CH2Cl2 molecules. This work clarifies the correlation between the molecular environment and magnetism of single-molecule magnets, which is helpful for their design guideline and future applications.

Synthesis, characterization, TD‐DFT, molecular docking, biological applications, and solvatochromic studies of some new metal complexes derived from semicarbazone of pyrano[3,2‐c]quinoline‐3‐carboxaldehyde

New Zn(II), Cd(II), VO(IV), and UO2(VI) solvatochromic complexes derived from 6‐ethyl‐4‐hydroxy‐2,5‐dioxo‐5,6‐dihydro‐2H‐pyrano[3,2‐c]quinoline‐3‐carboxaldehyde‐semicarbazone ligand (H2L) were synthesized and established by elemental analyses, spectral (IR, UV, NMR, mass spectra), molar conductivity measurements, magnetic susceptibility, and thermal gravimetric analysis (TGA). The ligand coordinates with metal ions through ONO chelating sites, forming an octahedral geometry arrangement, except UO2(VI) that showed pentagonal bipyramidal geometry. Using Coats–Redfern methodology, the kinetic parameters (Ea, A, ΔH, ΔS, and ΔG) of the thermal decomposition steps were calculated and discussed. The complexes showed solvatochromic behavior that used to estimate the ground and excited state dipole moments. Optimization and structural parameters were carried out by density function theory (DFT) at 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 and interrelated with the experimental results. The complexes were tested for antimicrobial efficiency against Gram‐positive bacteria, Gram‐negative bacteria, yeast, and fungi. Also, antitumor activity was investigated against HepG‐2 cell line. Finally, the new synthesized complexes upon subjecting to molecular docking and distinguishable results showed outstanding inhibition results of VEGFR‐2 via achieving a high stabilization level inside the largest pocket of 1YWN protein.

Synthesis and Characterization of Schiff Base of 2-Acetyl-5-Methylfuran Glyoxime Hydrazine and its Metal (II) Complexes and Their Evalution for Antibacterial and Antifungal Activities

Two hydrazone Schiff base was synthesized by the interaction of ethanolic solution of antiglyoxime hydrazine with 2-acetyl-5-methylfuran to obtain the Schiff base. The complexes of Mn(II), Fe(II), Ni(II) and Cu(II) and their Schiff base were synthesized and characterized based on solubility, percentage yield, elemental analysis, melting point and decomposition temperature, infra-red spectra (FT-IR), conductivity measurement, magnetic susceptibility and water of crystallisation. The ligand and the complexes were coloured and stable at room temperature. They were soluble in acetone, DMSO, ethanol, methanol, hexane, chloroform, carbontetrachloride, benzene and DMF but insoluble in distilled water. The melting point temperature of the ligand was 118oC while the decomposition temperatures for the complexes were found to be between 295-312oC. The molar magnetic susceptibility of the complexes were in the range of 3.55 x 10-3 – 1.42 x 10-2erg.G-2mol-1. Molar conductance values of 2.17 – 2.87Ω-1cm2mol-1 show non electrolytic nature of the complexes. The spectral data of the ligand showed bands in the range 1581–1607cm-1 revealing the formation of the azomethine group. A band between 760-795cm-1 indicates the metal nitrogen bonds. The elemental analysis of the complexes showed the metal ligand ratio of 1:2 (M:2L). The antibacterial and antifungal studies showed that the complexes exhibited higher antibacterial and antifungal activities than the ligand but lower than the reference drugs.

Zero-Field Splitting in Hexacoordinate Co(II) Complexes

A collection of 24 hexacoordinate Co(II) complexes was investigated by ab initio CASSCF + NEVPT2 + SOC calculations. In addition to the energies of spin–orbit multiplets (Kramers doublets, KD) their composition of the spins is also analyzed, along with the projection norm to the effective Hamiltonian. The latter served as the evaluation of the axial and rhombic zero-field splitting parameters and the g-tensor components. The fulfilment of spin-Hamiltonian (SH) formalism was assessed by critical indicators: the projection norm for the first Kramers doublet N(KD1) > 0.7, the lowest g-tensor component g1 > 1.9, the composition of KDs from the spin states |±1/2> and |±3/2> with the dominating percentage p > 70%, and the first transition energy at the NEVPT2 level 4Δ1. Just the latter quantity causes a possible divergence of the second-order perturbation theory and a failure of the spin Hamiltonian. The data set was enriched by the structural axiality Dstr and rhombicity Estr, respectively, evaluated from the metal–ligand distances Co-O, Co-N and Co-Cl corrected to the mean values. The magnetic data (temperature dependence of the molar magnetic susceptibility, and the field dependence of the magnetization per formula unit) were fitted simultaneously, either to the Griffith–Figgis model working with 12 spin–orbit kets, or the SH-zero field splitting model that utilizes only four (fictitious) spin functions. The calculated data were analyzed using statistical methods such as Cluster Analysis and the Principal Component Analysis.

Schiff Bases Ligands Derived from o-Phthalaldehyde and Their Metal Complexes with Cu2+ and Ni2+: Synthesis, Anti-Breast Cancer and Molecular Docking Study

The Schiff bases and their complexes have an observed biological efficacy, so in the current study it has been prepared, characterized and evaluated the biological activity of some Schiff bases and their metal complexes with copper and nickel and based on ortho-phathaldehyde as a primary compound. A new Schiff bases ligands and metal complexes {[Cu(L)n(H2O)2]Cl2.mH2O and [Ni(L)n].mH2O, where L=N',N'''-((1E,1'E)-1,2-phenylenebis(methanylylidene)) di(benzohydrazide) L1, N',N'''-((1E,1'E)-1,2-phenylenebis (methanylylidene)) di(isonicotinohydrazide) L2, 1,2-bis((E)-(2-(2,4,6-trichlorophenyl)hydrazono)methyl) benzene L3 ; n = 1, 2 ; m = 0, 1, 3/2, 5/2} have been synthesized and elucidated by mass, FT-IR, 13C and 1HNMR, molar conductivity, flame-atomic absorption, magnetic susceptibility, Powder-XRD and TG analysis. The results showed that the L1 and L2 ligands behave as a tetra-dentate donor and were associated with metal ions in a molar ratio of 1:1, while L3 ligand was bi-dentate donor and associated with metal ions in 1:2 molar ratio. In addition, the geometric shapes of the prepared complexes were tetrahedral and square planar for Ni2+ and Zn2+ complexes, and octahedral for Cu2+ complexes. The effect of cellular toxicity in the laboratory has been examined by MTT assay for all compounds against the MCF-7 cancer breast cell line and found to have low efficacy except [Cu(L3)2(H2O)2] Cl2.H2O (5). The copper complex's molecular docking has been performed with breast cancer proteins using the MOE program, and found to target ERα, CDK6 and EGFR proteins by binding to hydrogen bonds and pi-interactions. HIGHLIGHTS Synthesis new chemical compounds, which are some Schiff bases and their metal complexes with copper and nickel ions Characterization of chemical structure of synthesized compounds by mass, FT-IR, 13C and 1HNMR, molar conductivity, flame-atomic absorption, magnetic susceptibility, Powder-XRD and TG analysis Study the biological activity of synthesized compounds as anti-breast cancer Study of molecular docking of compounds that showed biological efficacy with proteins responsible for breast cancer cells GRAPHICAL ABSTRACT

Preparation, Characterization, Antioxidant and Antibacterial Studies of New Metal (II) Complexes with Schiff Base for 3-amino-1-phenyl-2- pyrazoline-5-one

A new ligand complexes have been synthesis from reaction of metal ions of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Pd(II) and Pt(II) with schiff base LH. 5-[(2-Hydroxy-naphthalen-1-ylmethylene)-amino]-2-phenyl-2,4-dihydro-pyrazol-3-one, this ligand was characterized by Fourier transform infrared (FTIR), UV-vis, 1H, 13CNMR, and mass spectra. All complexes were characterized by techniques micro analysis C.H.N, UV-vis and FTIR spectral studies, atomic absorption, chloride content, molar conductivity measurements and magnetic susceptibility. The ligand acts as bidentate, coordination through nitrogen atom from azomethin group and deprotonated phenolic oxygen atom. The spectroscopic and analytical measurements showed that the geometric shape of the prepared complexes is octahedral, while the square planar of the palladium and platinum complexes. The ligand and its complexes were having been screened for their antimicrobial activities and antioxidant

A Series of Metal–Organic Frameworks with 2,2′-Bipyridyl Derivatives: Synthesis vs. Structure Relationships, Adsorption, and Magnetic Studies

Five new metal-organic frameworks based on Mn(II) and 2,2'-bithiophen-5,5'-dicarboxylate (btdc2-) with various chelating N-donor ligands (2,2'-bipyridyl = bpy; 5,5'-dimethyl-2,2'-bipyridyl = 5,5'-dmbpy; 4,4'-dimethyl-2,2'-bipyridyl = 4,4'-dmbpy) [Mn3(btdc)3(bpy)2]·4DMF, 1; [Mn3(btdc)3(5,5'-dmbpy)2]·5DMF, 2; [Mn(btdc)(4,4;-dmbpy)], 3; [Mn2(btdc)2(bpy)(dmf)]·0.5DMF, 4; [Mn2(btdc)2(5,5'-dmbpy)(dmf)]·DMF, 5 (dmf, DMF = N,N-dimethylformamide) have been synthesized, and their crystal structure has been established using single-crystal X-ray diffraction analysis (XRD). The chemical and phase purities of Compounds 1-3 have been confirmed via powder X-ray diffraction, thermogravimetric, and chemical analyses as well as IR spectroscopy. The influence of the bulkiness of the chelating N-donor ligand on the dimensionality and structure of the coordination polymer has been analyzed, and the decrease in the framework dimensionality, as well as the secondary building unit's nuclearity and connectivity, has been observed for bulkier ligands. For three-dimensional (3D) coordination polymer 1, the textural and gas adsorption properties have been studied, revealing noticeable ideal adsorbed solution theory (IAST) CO2/N2 and CO2/CO selectivity factors (31.0 at 273 K and 19.1 at 298 K and 25.7 at 273 K and 17.0 at 298 K, respectively, for the equimolar composition and the total pressure of 1 bar). Moreover, significant adsorption selectivity for binary C2-C1 hydrocarbons mixtures (33.4 and 24.9 for C2H6/CH4, 24.8 and 17.7 for C2H4/CH4, 29.3 and 19.1 for C2H2/CH4 at 273 K and 298 K, respectively, for the equimolar composition and the total pressure of 1 bar) has been observed, making it possible to separate on 1 natural, shale, and associated petroleum gas into valuable individual components. The ability of Compound 1 to separate benzene and cyclohexane in a vapor phase has also been analyzed based on the adsorption isotherms of individual components measured at 298 K. The preferable adsorption of C6H6 over C6H12 by 1 at high vapor pressures (VB/VCH = 1.36) can be explained by the existence of multiple van der Waals interactions between guest benzene molecules and the metal-organic host revealed by the XRD analysis of 1 immersed in pure benzene for several days (1≅2C6H6). Interestingly, at low vapor pressures, an inversed behavior of 1 with preferable adsorption of C6H12 over C6H6 (KCH/KB = 6.33) was observed; this is a very rare phenomenon. Moreover, magnetic properties (the temperature-dependent molar magnetic susceptibility, χp(T) and effective magnetic moments, μeff(T), as well as the field-dependent magnetization, M(H)) have been studied for Compounds 1-3, revealing paramagnetic behavior consistent with their crystal structure.

Synthesis, characterization, antibacterial, antioxidant activities, density functional theory, and molecular docking studies of new organic metal complexes and links to application of corrosion inhibitors

The condensation reaction between 5‐amino‐1,3,4‐thiadiazole‐2‐thiol and 1,2‐dibromoethane to afford the ligand L was carried out in direct to obtain the desired organic ligand. New [Er(L)ClH2O]Cl2·3H2O, [Yb(L)(H2O)2]Cl3·4H2O, and [Ta(L)Cl2]Cl3·4H2O complexes have been prepared from (L) by reacting one mole from metal ions with one mole from L. In addition to their physical characteristics, they were described using spectroscopic techniques (infrared [IR], nuclear magnetic resonance [NMR], and UV–Vis), gas chromatography (GC)‐mass, and X‐ray powder diffraction. Further interpretation of complex structures was supported by measurements of molar conductivity, magnetic susceptibility, mole ratio, and thermodynamic investigations in addition to theoretical study through the use of density functional theory and characterization techniques. IR spectral data showed the mode of action of the neutral tetradentate L ligand and its coordination via two N‐amine and two S‐thiols. The octahedral geometry surrounding the central lanthanide ions was suggested by the magnetic moments, diffused reflectance, and spectral data. Molar conductivity results exposed that Yb(III) and Ta(V) chelates were 1:3 electrolytes and Er(III) chelate was 1:2 electrolyte. In addition, practically all the complexes demonstrated effective antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus species, via inhibition zone diameters in 9–15 mm mg−1 range. However, neither Candida albicans nor Aspergillus flavus species were susceptible to their antifungal effects. Finally, molecular docking (MOE) experiments showed the significant binding affinity of the ligand and its complexes with several 6KOC, 6LU4, and 6LU4 protein receptors. Finally, it is important to emphasize that these complexes may be potential antioxidant agents according to the biochemical results. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) methods were accustomed to examine the corrosion inhibition of aluminum silicon alloys (AlSi) in 1 M HCl solution. Experimental measurements indicate that the thiadiazole ligand reduces the corrosion rate.

Synthesis, Characterization and Antimicrobial Activities of Schiff Base Derived From Glyoximehydrazine and Substituted Furan and Their Metal (II) Complexes

A hydrazone Schiff base has been synthesized by the interaction of ethanolic solutions of antiglyoxime hydrazine with 2-acetyl-5-methylfuran to obtain the Schiff base L′. The complexes of Co(II), Ni(II) and Cu(II) of this Schiff base was synthesized and studied. The Schiff base and its metal(II) complexes were characterized based on solubility, percentage yield, elemental analysis, melting point/decomposition temperatures, infra- red spectral (FT-IR), conductivity measurement, magnetic susceptibility and water of crystallisation. Based on the results the prepared Schiff base and synthesized complexes are relatively soluble in most organic solvents but insoluble in distilled water. The melting point temperature of the ligand was 118oC while the decomposition temperature for metal complexes was found to be between 295 _320oC. The molar magnetic susceptibility of the complexes were in the range of 1.91 x 10-3 – 1.46 x 10-2erg.G-2mol-1. The molar conductance values of 2.00 – 3.00ohm-1cm2mol-1 indicating non electrolytic nature of the complexes. The spectral data of the Schiff base showed band at 1641cm-1, revealing the formation of the azomethine group in the Schiff base. A band between 776 and 791cm-1 indicate the metal nitrogen bond. The elemental analysis determination of the complexes and the Schiff base showed the metal ligand ratio of 1:2 (M:2L). The antibacterial and antifungal activities of the Schiff base and the metal(II) complexes were evaluated using disc diffusion method. The antibacterial assay was carried out on three pathogenic bacteria, Salmonella typhimurium, Proteus aureginosa and Staphylococcus aureus, and two fungi viz: Candida utilis and Saccharomyces cerevisiae. The Schiff base and the metal(II) compounds showed some antibacterial and antifungal activity.

Synthesis, characterization and antimicrobial activities of Schiff base complexes derived from Salicylaldehyde and amino acid (isoleucine)

Complexes of Fe(II), Co(II), Cu(II), and Zn(II) with a Schiff base derived from salicylaldehyde and isoleucine were successfully synthesized. All complexes were distinctly colored and were characterized by molar conductance, magnetic susceptibility, infrared and UV spectroscopy. Infrared spectroscopy shows the Schiff base ligand is coordinated to the central metal ion in a tridentate manner through the N-atom of the azomethine and two oxygen of the phenol and carboxylate. All complexes contain two ligands molecules per metal ion (ML2). An octahedral geometry is proposed for the metal complexes. Antimicrobial study of the complexes was undertaken against five pathogenic bacteria strains and two fungi, mucus species and Aspergillus fumigates. The result reveal that most of the complexes and particularly Co (II) and Zn (II) have a much enhanced activity against Staphyllococcus aureus, Escherichia coli and Klebsiella pneumoniae.

Molecular docking, synthesis and antimicrobial evaluation of metal complexes with Schiff base

The appearance of resistant bacteria was found to reduce the efficiency of antimicrobial therapies with the current antibiotics, thereby increasing the need for more efficient drugs for the treatment of infections. A microbial infection affects tremendously to the human health and antimicrobials are one of the mainly successful forms of chemotherapy which saves the human population from the risk of infectious diseases. In this regard, the present study involves synthesis of transition metal complexes have often shown the immense antimicrobial activity. In this article, metal complexes were synthesized using different metals such as of Zn(II), Hg(II), Pt(II) and Pd(II), using Schiff’s base derived from amino and carbonyl ligand. All the synthesized compounds were characterized using IR, NMR, and mass spectral data and also by UV–visible spectra, molar electric conductance, magnetic susceptibility and thermal studies. Moreover, the antimicrobial activities of metal complexes were demonstrated using both gram negative and gram positive bacteria. The synthetic series of title compounds 6a-d, the compounds 6c and 6d with platinum and palladium metal were found to be active. The complex 6c has shown excellent antimicrobial activity and the result was also confirmed by molecular docking.

Synthesis, Structural Studies and Antimicrobial Evaluation of Nickel(II) Bis-Complex of Schiff Base of S-Benzyldithiocarbazate

A tridentate nitrogen-oxygen-sulfur (NOS) S-benzyl(2-oxoindolin-3-ylidene)dithiocarbazate, HSBISA (HL1) ligand was synthesized via a condensation reaction between S-benzylditihocarbazate (SBDTC) and isatin. The produced ligand was reacted with nickel(II) acetate salt in 1:2 (metal:ligand) ratio to yield a brown Ni(SBISA)2 complex (2) (SBISA = monoanionic form of HL1). Characterization of HL1 and its Ni(II) complex was performed via elemental analysis, FT-IR, ICP-AES, UV-Vis spectroscopy and mass spectrometry, along with molar conductivity and magnetic susceptibility measurement. Slow evaporation of 2 from DMSO at room temperature led to a structure crystallizing in the monoclinic P21/a space group with a = 18.6860(3), b = 11.3037(2), c = 19.8993(3), b = 112.1897(10), V = 3891.86(11) Å3, wR2 (all data) = 0.0407 and R1 = 0.0386 for data with I > 2σ(I). The nickel(II) metal center is ligated by doubly-deprotonated NOS monoanionic tridentate HL1 ligands forming a neural distorted octahedral Ni(SBISA)2×2DMSO (2a) complex. The antimicrobial assays of both compounds were performed on selected pathogenic bacteria and fungi strains. HIGHLIGHTS Octahedral Ni(II) complex was synthesized using acetate salt Compound was characterized via physico-chemical analyses Structural studies were resolved via single crystal X-ray diffraction Compound 2a crystallized in a monoclinic system (P21/a space group) with cell parameters a = 18.6860 (3), b = 11.3037 (2), c = 19.8993(3), b = 112.1897 (10), V = 3891.86 (11) Å3, wR2 (all data) = 0.0407 and R1 = 0.0386 for data with I > 2σ(I) Compound was evaluated for its antimicrobial activity GRAPHICAL ABSTRACT

Structure and properties of phases from solid solutions YTIn1−x Al x (T = Ni and Cu)

Abstract YNiIn and YCuIn form complete solid solutions YNiIn1−x Al x and YCuIn1−x Al x , which were characterized on the basis of X-ray powder diffraction. The ZrNiAl type crystal structures (space groups P 6 ‾ 2 m $P\overline{6}2m$ ) of YNiAl (a = 0.70386(9), c = 0.38327(4) nm, wR 2 = 0.0424), YNiIn0.77Al0.23 (a = 0.73895(9), c = 0.37707(4) nm, wR 2 = 0.0498) and YCuIn0.63Al0.37 (a = 0.73404(7), c = 0.39045(4) nm, wR 2 = 0.0314) were refined from the single crystal X-ray diffraction data. Exemplarily the electronic structure of YNiAl was studied, manifesting substantial Ni–Al bonding within the three-dimensional [NiAl] substructure. Comparison of YNiAl with isotypic YNiIn shows stronger Ni–Al bonding as compared to Ni–In. Magnetic susceptibility measurements of YNiIn1−x Al x (x = 0.1, 0.2, 0.7 and 0.9), YNiIn and YNiAl in the temperature range 3–300 K indicated Pauli paramagnetic behaviour with molar magnetic susceptibility of about 0.15–0.22 × 10−3 emu/mol.