Schiff Base Ligand Research Articles

New Schiff bases and their vanadium complexes: Synthesis, characterization, and biological assessment for antibacterial and antiviral action

From the perspective of possible antiviral and antibacterial activity of vanadium‐based complexes, we report the synthesis of new Schiff base ligand (L4) and a new Schiff‐base‐vanadium complex (C2). Both the ligand and the complex were characterized by Fourier transform infrared spectroscopy and Nuclear magnetic resonance techniques. Single‐crystal X‐ray Diffraction analysis has been used to confirm the structure of ligand L4 and complex C2. In addition, L1–4 and C1–3 were tested for their antibacterial effects against Escherichia coli and Staphylococcus aureus. Among the compounds, L2 demonstrated the most potent inhibition of both bacteria, exhibiting the lowest values for minimum inhibitory concentration (CMI) and minimum bactericidal concentration (CMB) (CMI = 0.16, CMB = 0.31 against E. coli, and CMI = CMB = 0.16 against S. aureus). Additionally, L2 produced the largest inhibition zones with diameters of 15.5 ± 0.15 against E. coli and 14.5 ± 0.04 against S. aureus. Furthermore, the antiviral efficacy of L1, L2, L4, C1, C2, and C3 against RNA viruses was assessed. C2 and C3 exhibited the most potent antiviral activity among the tested compounds.

Development of mixed-ligand ruthenium complexes bearing phosphine and imine ligands for utilisation as catalysts in Suzuki-type C–C cross-coupling reactions

ABSTRACT Herein we report the development of two mixed-ligand ruthenium (II) complexes bearing phosphine and imine ligands, their thorough characterisation and their utilisation as homogeneous catalysts in Suzuki-type C–C cross-coupling reactions. Reactions of two tetradentate Schiff base ligands, derived from imidazole-2-carboxaldehyde and ethylenediamine (H2L1 ) or propylenediamine (H2L2 ), with [Ru(PPh3)3Cl2] in refluxing ethanol in the presence of NEt3 afforded two complexes of type [Ru(L1)(PPh3)2] and [Ru(L2)(PPh3)2], respectively. The solid-state structure of [Ru(L2)(PPh3)2] was determined by single crystal X-ray diffraction analysis. The molecular structure of [Ru(L1)(PPh3)2] was optimised by the DFT method. Electronic spectra of the complexes showed intense absorptions spanning over the visible and ultra-violet regions, the origin of which was probed with TDDFT calculations. Redox properties of the complexes were studied by cyclic voltammetry. These mixed-ligand ruthenium(II) complexes serve as efficient catalyst-precursors for Suzuki-type C–C cross-coupling reactions.

Synthesis, structural characterization and biological applications of mono- and binuclear Cu(II) and Ni(II) complexes with N2O2 Schiff bases

The present work aims to synthesize and characterize new Schiff base metal complexes (Cu(II) and Ni(II)) derived from 4,5-Dichloro-o-phenylenediamine and 3,5-Dichloro-2-hydroxyacetophenone. The synthesized Schiff base and their complexes have been characterized with the support of more than a few standard physicochemical techniques such as elemental analysis, spectroscopic, thermal, and cyclic voltammetry studies. Further the molecular structures are ascertained by computational methods like density functional theory (DFT) methods. The newly synthesized Schiff base ligand acts as ONNO donor tetradentate chelate and coordinated through an azomethine nitrogen and phenoxo oxygen atom to the Cu(II) and Ni(II). Moreover, all the newly prepared compounds exhibit moderate biological activity such as antibacterial. The synthesized compounds were screened for their antibacterial by the disc agar diffusion method. Spectral analysis exhibits square planar geometry for Cu(II) & Ni(II) mono and binuclear complexes. The antimicrobial results indicate that the homo binuclear copper (II) complex was more active than the other mono and binuclear complexes. The theoretical DFT calculations were applied to verify the molecular geometry of chelators and their complexes. The DFT optimized geometries of the complexes are in agreement with experimental observations.

Syntheses, Crystal Structures and Antimicrobial Activity of Copper(II) Complexes with the Ligand N,N'-Bis(4-bromosalicylidene)propane-1,2-diamine.

Three new copper(II) complexes, [CuClL] (1), [CuBrL]n (2) and [CuL(NCS)]n (3), derived from the Schiff base 2,4-dichloro-6-((2-pyrrolidin-1-ylethylimino)methyl)phenol (HL) have been prepared and characterized by spectroscopy methods, as well as single crystal X-ray determination. The Cu atom in complex 1 is in square planar coordination, and those in complexes 2 and 3 are in square pyramidal coordination. The Schiff base ligand coordinates to the Cu atoms through phenolate oxygen, imino nitrogen and pyrrolidine nitrogen. The antibacterial activities of the Schiff base and the three copper complexes have been assayed on the bacteria Staphylococcus aureus and Escherichia coli, and the yeast Candida parapsilosis.

Novel Ni(II) and Zn(II) Schiff base metal chelates as promising DNA binder, Antioxidant and Antifungal agents

<p>Schiff base ligands and their 3d-metal chelates have gained significant attention due to various applications in various scientific platforms. Due to their chelating propensity, they possess a wide range of biological, biochemical, catalytic, clinical, dying, and pharmacological properties.<strong> </strong>Here, in present studies,<strong> </strong>two novel Ni(II) and Zn(II) transition metal chelates have been synthesized by condensing their metal salts with Schiff base ligand 4-chloro-2-(2,5-dimethoxybenzylideneamino)-5-nitrophenol<strong> </strong>originated from 2,5-dimethoxybenzaldehyde and 2-amino-4-chloro-5-nitrophenol. The synthesized Schiff base ligand and its metal chelates have been Spectro-chemically examined by FT-IR, UV-Vis absorption spectroscopy, Mass Spectrometry, <sup>1</sup>HNMR, Thermogravimetric analysis (TGA) and Powdered-XRD. These compounds are biologically reactive and exhibit antifungal, antioxidant, and DNA-binding activity. The Ni(II) metal chelate gives better biological activity than the Zn(II) metal chelate and parent Schiff base ligand.</p>

DNA and bovine serum albumin protein (BSA) interaction of antitumor supramolecular nickel(II) complex: Inference for drug design

To explore the therapeutic potential of supramolecular nickel(II) Schiff base self-assemble complexes, the Schiff base ligand (N, N′-bis(salicylidene)-1,3-diamino-2-propanol) and its Ni(II) complex [Ni2(H2L)2(NCS)2(CH3OH)2](CH3OH)2 were synthesized. Characterization by X-ray crystallography (for the complex), FT-IR, UV–Vis spectroscopy, 1HNMR and elemental analysis (CHN) were performed. Single-crystal X-ray structure of the complex exhibited a distorted octahedral geometry in which each nickel(II) center, in the asymmetric unit, was six coordinated with three N atoms and three O atoms (from Schiff base ligand, methanol and NCS). In vitro Fish Sperm DNA (FS-DNA) and Bovine Serum Albumin (BSA) binding studies of the complex employed UV–Vis and fluorescence spectroscopy, cyclic voltammetry, viscosity measurement and molecular docking. The complex indicated a good binding propensity to BSA and was also bound to FS-DNA, preferably via intercalation. The outputs of the molecular docking study confirmed the experimental results. The complex was found to exert high anticancer activity against the gastric and prostate cancerous cells with putative selective anticancer properties. The death-induced mechanism underlying the complex is mainly related to the intercalator interactions, which may result in apoptosis-programmed cell death.

Synthesis, crystal structure and properties of poly[di-μ3-chlorido-di-μ2-chlorido-bis[4-methyl-N-(pyridin-2-ylmethylidene)aniline]dicadmium(II)

The title coordination polymer with the 4-methyl-N-(pyridin-2-ylmethylidene)aniline Schiff base ligand (L, C13H12N2), [Cd2Cl4(C13H12N2)] n (1), exhibits a columnar structure extending parallel to [100]. The columns are aligned in parallel and are decorated with chelating L ligands on both sides. They are elongated into a supramolecular sheet extending parallel to (01\overline{1}) through π–π stacking interactions involving L ligands of neighbouring columns. Adjacent sheets are packed into the tri-periodic supramolecular network through weak C—H...Cl hydrogen-bonding interactions that involve the phenyl CH groups and chlorido ligands. The thermal stability and photoluminescent properties of (1) have also been examined.

Antifungal and antibacterial activity of two new Ni(II) complexes of a pyrazole-appended thiophene containing bidentate schiff-base ligand: Synthesis, spectroscopy and crystal structures

A new pyrazole-appended thiophene containing Schiff-base ligand, N-(thiophene-2-ylmethyl)-1-(5-methyl-1H-pyrazol-3-yl)methanimine, (MPATA) (1) and its two new di- and mononuclear Ni(II) complexes, [Ni2(MPATA)4 (µ-Cl)2]Cl2 (2) and [Ni(MPATA)3](ClO4)2 (3), respectively, are reported. All the synthesized compounds have been thoroughly characterized by several physico-chemical and spectroscopic studies. Single crystal X-ray diffraction studies have identified 2 as a chloro‑bridged di-nuclear cationic complex, while 3 as a mononuclear distorted octahedral one. In 2, coordination to each metal centre has been occurred by two molecules of ‘NN’ bidentate MPATA and each Ni(II) centre assumes a distorted octahedral geometry. On the other hand, in 3, three molecules of the ‘NN’ bidentate MPATA coordinate to the Ni(II) centre. Both the complexes 2 and 3 exhibit significant hydrogen bonding and intramolecular π···π stacking interactions. All the three compounds have been found to display significant antifungal activity against plant pathogen funguses Colletotrichum siamense (CS) and Fusarium equisetum (F.E) and antibacterial activity against gram-positive and gram-negative bacteria, but no such effects have been found against human pathogen fungus Candida albicans sc5314.

Novel Co(II), Cu(II) and Fe(II) Pentadentate Schiff base complexes: Synthesis, characterization, antimicrobial, antioxidant, and molecular docking studies

The compound H2L, which is a ligand with five coordinating atoms, consisting of three nitrogen atoms and two sulfur atoms (N3S2), was reacted with Fe(OAc)2, Cu(OAc)2.H2O, and Co(OAc)2·4H2O to form the corresponding metal complexes ([FeL], [CuL], [CoL]). Many techniques, including NMR (for ligand), FT-IR, UV–Vis, elemental analysis, and molar conductivity, were used to characterize the synthesized compounds. According to the spectrum of data, complex molecule structures have a distorted triangular bipyramidal geometry with five coordination locations. The compounds that exhibit non-electrolyte behavior in solution do not possess any conductivity features. Evaluation was performed to determine the antioxidant activity of the synthesized compounds in comparison to the stable free radical DPPH. The ligand and its metal complexes were evaluated for antibacterial activity against several Gram-positive and Gram-negative bacteria, as well as a yeast strain. In comparison to the common antibiotic Amoxycillin/Clavulanic Acid (AMC-30), the Schiff base ligand (H2L) and its Cu(II) metal complex showed noticeably larger inhibitory zones against S. aureus. All the compounds showed a high negative binding affinity for S. aureus amino acid molecules when they were docked. The results indicated that the metal complexes, particularly the cobalt complex, exhibited a higher affinity for binding compared to the free ligand.

Chiral 4f and 3d-4f Complexes from Enantiopure Salen-Type Schiff Base Ligands

This review summarizes the structural characteristics and physicochemical properties of chiral 4f and 3d-4f complexes based on enantiopure salen-type Schiff base ligands. The chirality originates from the enantiopure diamines and is imparted to the Schiff base ligands and complexes and finally to the crystal structures. The reported enantiopure Schiff base ligands derive from the condensation of aromatic aldehydes, such as salicylaldehyde and its various derivatives, and the enantiopure diamines, (1R,2R) or (1S,2S)-1,2-diamino-cyclohexane, (1R,2R) or (1S,2S)-1,2-diamino-1,2-diphenylethane, (R) or (S)-2,2′-diamino-1,1′-binaphthalene, and 1,2-diaminopropane.

Design, synthesis, and pharmacological efficacy of sonication-irradiated nanostructured transition metal (II) designed macrocyclic complexes

The synthesis of transition metal (II) complexes from aspartic acid was accomplished by using sonication irradiation in this work. Sonication irradiation is a straightforward and efficient technique for synthesis. Physiological and spectroscopic studies were carried out to investigate the process of assembling nanostructured complexes. Using the serial dilution (2-fold) and free radical scavenging (DPPH) procedures, the antioxidant and antibacterial activity were assessed, respectively. Various bacteria, including Gram-positive and Gram-negative strains and fungi, were tested to determine the antimicrobial efficacies of the macrocyclic ligand and its accompanying metal complexes. The inhibitory results on microbes showed that metal complexes had more potent antibacterial effects than their Schiff base ligands. The findings demonstrated that the biological activity had a positive impact. Sonication irradiation of some complexes increased the movement of those complexes at concentrations ranging from 3.125 to 6.250 μg/ml (MIC). The Gaussian 09 software was utilized to simulate the three-dimensional structure of the complexes, the chemical reactivity of the produced macrocyclic ligand, and the binding energy of its complexes’ EHOMO and ELUMO energies using the B3LYP Density Functional Theory (DFT) method. This method is well-suited for pharmaceutical applications in the real world since it requires little effort to set up, produces a high yield, and requires a relatively small amount of solvent.

Synthesis, crystal structures and urease inhibition of nickel(II), copper(II), zinc(II) and molybdenum(VI) complexes derived from N,n’-bis(4-bromosalicylidene)-1,3-propanediamine

Three new trinuclear complexes containing either nickel(II), copper(II) or zinc(II), [Ni3L2(NO3)2(CH3OH)2]·2CH3OH (1), [Cu3Br2L2] (2), [Zn3L2(NCS)2(CH3OH)2]·0.5CH3OH·0.5H2O (3), and a new dioxidomolybdenum(VI) complex, [MoO2L] (4), have been prepared from the bis-Schiff base N,N’-bis(4-bromosalicylidene)-1,3-propanediamine (H2L) with various metal salts in methanol. The complexes were characterized by elemental analysis, IR and UV–Vis spectra. Molecular structures were confirmed by single crystal X-ray diffraction experiments. The Ni ions in 1 adopt an octahedral coordination environment, bridged by phenolate oxygen and nitrate ligands. The Cu ions in 2 are square pyramidal and square planar, and the Zn ions in 3 are square pyramidal and octahedral. The metal atoms in 2 and 3 are bridged by phenolate oxygen donors. The Mo ion in 4 is octahedral. The Schiff base ligand coordinates to the metal atoms through two phenolate O and two imino N donors. Biological assays revealed that the nickel and copper complexes have effective urease inhibition.

Rapid and reliable ratiometric fluorescence detection of nitro explosive 2,4,6-trinitrophenol based on a near infrared (NIR) luminescent Zn(II)-Nd(III) nanoring

Rapid and quantitative detection of 2,4,6-trinitrophenol (TNP) is very crucial for homeland security, military application, and environment protection. Herein, a nine-metal Zn(II)-Nd(III) nanoring 1 with a diameter of 2.3 nm was constructed by the use of a long-chain Schiff base ligand, which shows ratiometric fluorescence response to TNP with high selectivity and sensitivity. The fluorescence sensing behavior of 1 to TNP is expressed by a first-order equation I1060nm/I560nm = -0.0128*[TNP] + 0.9723, which can be used to quantitatively analyze TNP concentrations in solution. The limits of detection (LODs) to TNP based on the ligand-centered (LC) and Nd(III) emissions of 1 are 5.93 μM and 3.18 μM, respectively. The fluorescence response mechanism to TNP is attributed to the competitive absorption effect and photoinduced electron transfer (PET). The luminescence quenching of 1 is dominated by static process.

Synergistic exploration of antimicrobial potency, cytotoxicity, and molecular mechanisms: A tripartite investigation integrating in vitro, in vivo, and in silico approaches for pyrimidine‐based metal (II) complexes

We synthesized and characterized bioactive metal (II) complexes from a pyrimidine‐based Schiff base ligand, 4‐[2‐(4‐chlorobenzylidene) hydrazinyl]‐7H‐pyrrolo[2,3‐d]pyrimidine. Through thorough elemental analysis and various physicochemical techniques, we characterized both the ligand and its Zn(II), Cd(II), and Hg(II) complexes. Coordination of the metallic ion was established via nitrogen atoms from the ligand's pyrrolo and pyrimidine rings, yielding tetrahedral complexes of the type [M(PPHpCB)2]. These complexes are identified as non‐electrolytes due to their low molar conductance. Furthermore, we investigated the coordination behavior of the pyrimidine‐based Schiff base ligand (HPPHpCB) with metal ions through comprehensive spectroscopic analysis. 1H NMR spectral data showed bonding between HPPHpCB and metal ions, while UV spectra confirmed intra‐ligand and ligand‐to‐metal charge transfer transitions, indicating coordination through nitrogen atoms. The determination of tetrahedral geometry for metal complexes confirmed their diamagnetic properties. Analysis using 13C NMR and electrospray ionization mass spectra (ESI‐MS) revealed variations in chemical shifts, confirming successful complex formation and elucidating structural modifications, electronic interactions, and metal–ligand coordination modes. Moreover, evaluation of in vitro antimicrobial activities using the minimum inhibitory concentration (MIC) approach revealed significant antibacterial and antifungal activities for Hg(II) and Cd(II) complexes, respectively. The Hg(II) complex displayed superior antioxidant activity, while Zn(II) and Cd(II) complexes also demonstrated considerable potential. In vivo, cytotoxicity assessments against Artemia salina provided insights into the cytotoxic properties of ligands and metal complexes. Computational techniques suggested their potential in combating infectious ailments. Overall, our study establishes the synthesis, characterization, and multifaceted biological activities of metal (II) complexes derived from the pyrimidine‐based Schiff base ligand, highlighting their promising role in combating various infectious diseases.

Sulfanilamide and 2‐hydroxy acetophenone driven Schiff base metal complex synthesizing, identification, and promising bioactivity

It has been possible to create complexes of metals from the Schiff base ((E)‐4‐(2‐hydroxy‐1‐phenylethylideneamino) benzenesulfonamide) (Sn.HA), which is generated from sulfanilamide and 2‐hydroxy acetophenone. These substances have been identified using various physicochemical methods, featuring mass spectral analysis, melting point, (inductively coupled plasma mass spectrometry [ICP‐MS]), Proton nuclear magnetic resonance (1H NMR), Fourier transform infrared (FTIR) spectroscopy, ultraviolet (UV) spectroscopy, elemental analysis, conductance measurements, electron spin resonance (ESR), and magnetic susceptibility. Most complexes are non‐electrolytes, according to the determined molar conductance values. Spectroscopic analyses indicate coordination of the majority of complexes by 2 C=N groups and 2 (OH) phenolic groups of ligand in a 2 L:1 M molar ratio in a consistent octahedral configuration [L2‐M‐(H2O)2], (L) Schiff base ligand (Sn.HA) and (M) metal, bacteria Gram‐negative (Pseudomonas aeruginosa and Escherichia coli), bacteria Gram‐positive (Streptococcus pneumonia and Bacillus subtilis), and antifungal (Candida albicans and Aspergillus fumigatus) have all been tested on complexes to check the activity of antibacterial and antifungal, with the metal complexes showing promising activity, where the unbound ligand is less active than the metal complexes.

Laminated dihydrazone Zn(II) coordination polymer with prospects for sensory and multifunctional biomedical applications

This study introduces a new laminated coordination polymer, {[Zn3(HL)2(H2O)6](SO4)2⋅1.5dmf·2.5H2O}n (1), synthesized through the direct interaction of ZnSO4·7H2O with dihydrazone Schiff base ligand (H2L = 2,6-diacetylpyridine bis(isonicotinoylhydrazone)) at room temperature. Comprehensive characterization of the compound, employing various methods (SCXRD, PXRD, IR, TGA) revealed different coordination surrounding of metal atoms and a combination of photoluminescent properties and biological activity. The polymeric layers are corrugated along the b-axis, mutually intertwined forming channels filled with outer sphere anions (SO42-) and solvent molecules (water and dmf). It was shown that solvent molecules have a decisive influence on the photoluminescent properties of the compound. The partial removal of water molecules leads to increased photoluminescence, the intensity of which doubles compared to the synthesized crystals. Furthermore, the compound demonstrates robust antibacterial effects against four Gram+ positive and two Gram- negative bacteria. In addition, its impact on cell proliferation, both in cancerous and non-cancerous cells, reveals the compound's antiproliferative effect on breast cancer cells in vitro, coupled with biocompatibility with human fibroblasts. This multifaceted approach positions the synthesized polymer as a promising candidate with vast potential for applications in luminescent materials and biomedical research.

Gadolinium Schiff-base complex on nanocomposite of graphene oxide magnetic nanoparticles as a robust, reusable and chemoselective nanocatalyst in the C–C coupling reactions

Graphene is an important phase of carbon, which is easily available and oxidable to graphene oxide with a variety of applications. Therefore in this work, graphene oxide (GO) was synthesized, and further it was magnetized by nickel magnetic nanoparticles. The surface of graphene oxide magnetic nanoparticles (Ni-GO MNPs) was modified with (3-aminopropyl)triethoxysilane (APTES). On the other hand, (3,4-bis(−(2-hydroxybenzylidene)amino)phenyl)(phenyl)methanone Schiff-base ligand (bis(HBAPM)) was synthesized using condensation of salicylaldehyde and 3,4-diaminobenzophenone. In the next step, bis(HBAPM) was immobilized on the surface of modified Ni-GO MNPs toward synthesis of immobilized Schiff-base on Ni-GO MNPs (bis(HBAPM)@Ni-GO MNPs) as a heterogeneous Schiff-base ligand. In the final step, the gadolinium catalyst was stabilized on its surface (Gd-bis(HBAPM)@Ni-GO MNPs) as a robust, reusable, efficient, chemoselective, and novel nanocatalyst. Gd-bis(HBAPM)@Ni-GO MNPs were characterized by nitrogen adsorption/desorption, FT-IR, SEM imaging, EDS analysis, WDX analysis, XRD, and VSM analysis. After the characterization of Gd-bis(HBAPM)@Ni-GO MNPs, its catalytic performance was employed as a highly practical, retrievable, stable, and hybrid organic–inorganic catalyst in the carbon–carbon coupling of the Suzuki reaction. Due to the recoverability and heterogeneous nature of Gd-bis(HBAPM)@Ni-GO MNPs, it can recycled again for 5 runs.

Antiferromagnetic resorcinol bridged dinuclear square-planar copper (II) complexes: Syntheses, structural, spectroscopic and magnetic properties

A new C2-symmetric Schiff base ligand (H2L) featuring a core resorcinol bridging unit has been created, utilizing the Duff formylation reaction followed by the Schiff base condensation reaction. The ligand was characterized by various spectroscopic techniques. Cu(II) salts with varying coordinating anions (Cl− and SCN−) in methanol were allowed to react with this ligand in a 2:1 M ratio to create dinuclear Cu(II) complexes. The complexes were isolated in pure form and characterized by, elemental analysis,single crystal X-ray crystallography and various spectroscopic techniques. X-ray analysis discloses that both complexes are dinuclear, where the ligand (H2L) being tridentate in nature, coordinates to Cu(II) through its two N donor atoms and one O donor atom in the equatorial positions. The respective anions (−Cl− for 1 and –SCN− for 2) coordinate to Cu(II) to complete its square planar geometry. Temperature dependent magnetic susceptibility measurements indicate weak antiferromagnetic exchange interactions with a coupling constant of J = −5.9(1) cm−1 and g = 2.148(1) for 1 and J = −10.08(1) cm−1 and g = 2.106(1) for 2.

Unveiling the therapeutic potential of organotellurium(IV) Schiff base complexes through structural elucidation, antimalarial, antioxidant and antimicrobial studies

Infectious diseases have long been a formidable adversary to human health and well-being, presenting a persistent global challenge with far-reaching implication for individuals, communities and societies at large. Thus, with the aim of a combating agent against malarial and oxidant causing ailments, the newly synthesized Organotellurium(IV) complexes with a hydroxynaphthaldehyde Schiff base ligand are proposed in the present research. The structures of the complexes were established through various physical and spectral analysis. The weak electrolytic (8.77 to 35.08 ohm−1 cm2 mol−1) and crystalline nature of the compounds were demonstrated by molar conductivity and TGA, respectively. The ligand and complexes (7a-7f) shows molecular ion peaks at m/z 458.3563, 726.1039, 713.6978, 727.6179, 799.4780, 771.3178 and 799.3978 amu which were well consistent with their formula, revealing formation of compounds. The shifting of ligand's azomethine peak (7.74 ppm) and disappearance of naphthyl hydroxyl proton (12.28 ppm) in 1H NMR spectra confirmed the chelation of ligand with metal ion in proposed manner. In the FT-IR spectra, the complexation of ligand with metal ion was confirmed by disappearance of hydroxyl group (3355 cm−1) band and shifting of C = N (1245 cm−1) and CO (1632 cm−1) band whereas appearance of Te-O (of 285–293 cm−1) and Te-N (458–467 cm−1) bands, revealed the bonding of metal with metal and octahedral nature of the complexes. Optimized structures, HOMO-LUMO energies and associated chemical reactivity descriptors of the compounds were computed by DFT calculations. The in vitro studies demonstrate that the complexes 7c (1.06 ± 0.11 μM) and 7f (1.22 ± 0.05 μM) exhibited moderate inhibition of the Plasmodium falciparum 3D7 strain, complexes 7a (100.96 ± 0.32 μg/mL) and 7d (96.32 ± 0.40 μg/mL) demonstrated the highest free radical quenching ability. Complex 7c displayed the highest antibacterial actions, whereas 7f exhibited the highest antifungal actions against the tested pathogens. Molecular docking and ADMET studies demonstrated enhanced binding affinity of the complexes compared to the Schiff base and their drug-like qualities.

Studies of the nonlinear optical properties of a synthesized Schiff base ligand using visible cw laser beams

The synthesized Schiff base ligand (compound Z1) is analyzed by IR, mass, 1HNMR, and 13CNMR spectroscopies. Computational chemical modeling is performed to examine the geometry optimization and molecular structure of compound Z1 by using the DFT/ WB97XD/6-31+G(d,p) method. The parameters HOMO–LUMO energies with nonlinear optical (NLO) properties are computed. The results indicate good agreement between experimental and theoretical data, so that compound Z1 to have good NLO properties. The NLO properties of the compound Z1 are examined under excitation with a 473 nm, cw, low power laser beam via two techniques, viz., diffraction patterns (DPs) and the standard Z-scan techniques. As high as 3.03 × 10−11 m2 W−1 of the compound Z1 of the nonlinear refractive index (NLRI), n2, is obtained via the DPs. Both static and dynamic all –optical switching (SAOS and DAOS) are tested using 473 nm and 532 nm cw low power laser beams.