Zinc Complexes Research Articles

Hydrates of N-(Anthracen-9-ylmethyl)-3-(1H-imidazolium-1-yl)propan-1-ammonium Zinc(II) or Cobalt(II) 2,6-pyridinedicarboxylate: Inter-conversions, assembling and utilities

Different hydrates [(H3anthraimmida)M(26pdc)2]⋅nH2O⋅mCH3OH {(M = Co; n, m = 4, 0 or n, m = 4.5: 0 or n, m = 2, 2 and M = Zn; n, m = 4, 0 or n, m = 1, 1.5) N-(anthracen-9-ylmethyl)-3-(1H-imidazolium-1-yl)propan-1-amommonium cation (H3anthraimmida), 2,6-pyridinedicarboxylates (26pdc)} of N-(anthracen-9-ylmethyl)-3-(1H-imidazolium-1-yl)propan-1-ammonium zinc(II) or cobalt(II) 2,6-pyridinedicarboxylate were crystallized from solutions of same reacting components but each at different concentration. Among these hydrates, the ones having methanol also as solvent of crystallization were metastable, easily transformed to corresponding tetrahydrate. The crystals of the metastable hydrate of zinc complex (monoclinic) transformed to tetrahydrate (triclinic) by halving of unit cell dimension of the metastable form. This transformation was observed under an optical microscope in real time. The transformation of the metastable hydrate of the cobalt complex also resulted the corresponding tetrahydrate. In this case, the unit-cell of the metastable form was doubled than the unit-cell dimension of the corresponding tetrahydrate. The crystals of the metastable form of the zinc complex (monoclinic) transformed to the tetrahydrate (triclinic) though a top-down approach, whereas the crystals of the metastable hydrate of the cobalt complex underwent a bottom-up approach. Diffused light scattering studies have revealed that the average particle sizes of the metastable hydrate of the zinc or cobalt complex dissolved in methanol, were decreased or increased upon addition of water to the solution. The zinc complexes in methanol showed aggregation induced emission enhancement at 415 nm upon addition of water.

DNA cleaver with improved phosphatase and cytotoxic activity of a series of N2O‐based zinc(II) complexes

Three new Zn(II) Schiff base complexes, [ZnLCl2] (1), [ZnLBr2] (2) and [ZnL(SCN)2] (3), have been synthesized by adding Zn(II) salts of chloride and bromide to a compartmental ligand with NNO donor prepared through the simple condensation of pyridine‐2‐carboxaldehyde and a substituted aniline. The complexes have been identified using standard physicochemical methods, and their solid‐state structures have been determined through single‐crystal X‐ray analysis. The phosphatase‐like activity of all three complexes has been investigated using 4‐NPP as the model substrate in a DMSO/water medium. Complex 1 exhibits the highest level of phosphatase activity. The reactivity trend shows that complex 1 > complex 2 > complex 3. A plausible mechanism and the causes underlying the activity trend have been explored through DFT study, ESI‐mass spectra and 31P experiments. Complex 1 shows promising potential for use in gene‐targeted therapeutics due to its remarkable performance in DNA digestion. The excellent DNA cleavage result of complex 1 has led to the investigation of its molecular docking interaction with the liver cancer 2 receptor to study its anti‐liver cancer activity. Furthermore, in vitro anticancer activity of complex 1 also shows excellent antiproliferative activity against hepatocellular carcinoma.

Novel hydroxy-tagged bis-dihydrazothiazole derivatives: Synthesis, antimicrobial capacity and formation of some metal chelates with iron, cobalt and zinc ions

Until today, microbialinfectionsepitomize a seriousuniversal health threat. Subsequently, developing a potential antimicrobialprototype remains an urgent, global necessity. Despite several reports discussing the biological utility of some bis-thiazoles, the use of bis-dihydrazothiazoles and their corresponding metal chelates as potent antimicrobials, is yet to be explored. The current report outlines an attempt to fill that void by representing a successful synthesis of a new class of bis-dihydrazothiazoles as well as three of their transition metal chelates and their use as potential antimicrobials. This report presents the design of some novel hydroxy-tagged bis-dihydrazothiazoles 6a-e and bis-dihydrazothiazolones 9a-evia the reaction of a bis-aldehyde thiosemicarbazone 3, as a common synthetic precursor, with two groups of hydrazonoyl halide derivatives 4a-e and 7a-e. The chelation affinity of these novel bis-dihydrazothiazoles to behave as neutral tridentate ligands coordinating to the metal ions; Fe(III), Co(II), or Zn(II) through azomethine-N, thiazole-S, and azo-N atoms to form metal complexes with a metal/ligand ratio of 2:1 was confirmed. In-vitro, antimicrobial screening of the novel hydroxy-tagged bis-dihydrazothiazole derivatives, as well as a selected group of their transition metal chelate complexes [M2L], was inspected, and the data weremeasured incomparisonto those of ketoconazole and gentamycin as antimicrobial reference standards. Most bis-dihydrazothiazoles 6a-e and bis-dihydrazothiazolones 9a-e showed decent to excellent antimicrobial activities against the screened microbes, but the chloro-substituted bis dihydrazothiazole derivatives 6c and 9c showed exceptional inhibition of Bacillus subtilis (20 mm), Escherichia coli (25 mm), and Candida albicans (19 mm), and Salmonella typhimurium (19 mm), respectively. Additionally, amongst the three synthesized metal complexes [M2L], only the zinc complex, [Zn2L] showed remarkable inhibition of both Staphylococcus aureus (21 mm) and Salmonella typhimurium (19 mm) compared to the reference standard Gentamycin, and was more potent than the free ligand, 6a itself (no activity and 11 mm respectively). Antimicrobial inspection was assessed by the agar well diffusion assay method against all bacterial and fungal strains. Magnetic moment, diffused reflectance, FT-IR, 1H NMR, molar conductivity, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscope(SEM) were among the many techniques used to elucidate the structures of all novel hydroxy-tagged bis-heterocyclic ligands and their metal chelate complexes.

Preparation and characterization of Arctium lappa L. polysaccharide-Zn(II) complex and evaluation of its immune activity

A novel Arctium lappa L. polysaccharide zinc (ALP-Zn) complex was synthesized with success. The structural characteristics, stability, and in vitro digestive properties of ALP-Zn were studied. Moreover, the immunoreactivity of ALP-Zn on murine bone marrow-derived dendritic cells (BMDCs) was investigated by examining surface molecule expression, cytokine production and endocytosis. The results showed that the weight-average molecular weight (Mw) of ALP-Zn was 60,268 Da. ALP-Zn mainly consisted of fructose, arabinose, galactose, and glucose in a mass ratio of 50.74:27.94:12.49:7.26. Zn-O characteristic peak was identified by fourier transform infrared spectroscopy at 433.42 cm−1, indicating that zinc was successfully complexed with ALP. The stability and in vitro digestive properties suggested that ALP-Zn had good stability and biological acceptability. Furthermore, ALP and ALP-Zn demonstrated excellent immunological effects on dendritic cells (DCs). After being treated with ALP and ALP-Zn, CD80 and CD86 expression on the surface of DCs were increased and DCs maturation was induced. Moreover, ALP and ALP-Zn also significantly reduced DC endocytosis and increased cytokine (IFN-γ, TNF-α, IL-1β and IL-6). As a consequence, ALP-Zn complex could be as a potential zinc supplement with immune properties.

Structure and in vivo psoralen DNA crosslink repair activity of mycobacterial Nei2.

Mycobacterium smegmatis Nei2 is a monomeric enzyme with AP β-lyase activity on single-stranded DNA. Expression of Nei2, and its operonic neighbor Lhr (a tetrameric 3'-to-5' helicase), is induced in mycobacteria exposed to DNA damaging agents. Here, we find that nei2 deletion sensitizes M. smegmatis to killing by DNA inter-strand crosslinker trimethylpsoralen but not to crosslinkers mitomycin C and cisplatin. By contrast, deletion of lhr sensitizes to killing by all three crosslinking agents. We report a 1.45 Å crystal structure of recombinant Nei2, which is composed of N and C terminal lobes flanking a central groove suitable for DNA binding. The C lobe includes a tetracysteine zinc complex. Mutational analysis identifies the N-terminal proline residue (Pro2 of the ORF) and Lys51, but not Glu3, as essential for AP lyase activity. We find that Nei2 has 5-hydroxyuracil glycosylase activity on single-stranded DNA that is effaced by alanine mutations of Glu3 and Lys51 but not Pro2. Testing complementation of psoralen sensitivity by expression of wild-type and mutant nei2 alleles in ∆nei2 cells established that AP lyase activity is neither sufficient nor essential for crosslink repair. By contrast, complementation of psoralen sensitivity of ∆lhr cells by mutant lhr alleles depended on Lhr's ATPase/helicase activities and its tetrameric quaternary structure. The lhr-nei2 operon comprises a unique bacterial system to rectify inter-strand crosslinks.IMPORTANCEThe DNA inter-strand crosslinking agents mitomycin C, cisplatin, and psoralen-UVA are used clinically for the treatment of cancers and skin diseases; they have been invaluable in elucidating the pathways of inter-strand crosslink repair in eukaryal systems. Whereas DNA crosslinkers are known to trigger a DNA damage response in bacteria, the roster of bacterial crosslink repair factors is incomplete and likely to vary among taxa. This study implicates the DNA damage-inducible mycobacterial lhr-nei2 gene operon in protecting Mycobacterium smegmatis from killing by inter-strand crosslinkers. Whereas interdicting the activity of the Lhr helicase sensitizes mycobacteria to mitomycin C, cisplatin, and psoralen-UVA, the Nei2 glycosylase functions uniquely in evasion of damage caused by psoralen-UVA.

Zinc-Catalyzed Cyclization of Alkynyl Derivatives: Substrate Scope and Mechanistic Insights.

Novel alkyl zinc complexes supported by acetamidate/thioacetamidate heteroscorpionate ligands have been successfully synthesized and characterized. These complexes exhibited different coordination modes depending on the electronic and steric effects of the acetamidate/thioacetamidate moiety. Their catalytic activity has been tested toward the hydroelementation reactions of alkynyl alcohol/acid substrates, affording the corresponding enol ether/unsaturated lactone products under mild reaction conditions. Kinetic studies have been performed and confirmed that reactions are first-order in [catalyst] and zero-order in [alkynyl substrate]. DFT calculations supported a reaction mechanism through the formation of the catalytically active species, an alkoxide-zinc intermediate, by a protonolysis reaction of the Zn-alkyl bond with the alcohol group of the substrate. Based on the experimental and theoretical results, a catalytic cycle has been proposed.

Innovative bis-dihydrazothiazolone derivatives with a 1,4-xylenyl spacer: Design, antimicrobial prospective and construction of several transition metal chelates with iron, cobalt and zinc

Several new xylenyl-spaced bis-dihydrazothiazoles 6a-e and bis-dihydrazothiazolones 9a-e were synthesized by the simple reaction between bis-thiosemicarbazone 3 as a common synthetic scaffold, with two series of hydrazonoyl halides derivatives 4a-e and 7a-d. The chelation ability of these novel bis-dihydrazothiazole derivatives to perform as neutral tridentate ligands and coordinate to transition metal ions; Fe(III), Co(II), or Zn(II) through azomethine-N, thiazole-S, and azo-N atoms to form metal complexes with a metal/ligand ratio of 2:1 was elucidated. Diffused reflectance, magnetic moment, 1HNMR, FT-IR, TGA, and molar conductivity, were used to interpret the structures of all new xylenyl-spaced bis-heterocyclic compounds and their metal chelates. In-vitro, antibacterial and antiviral screening of these innovative xylenyl-spaced bis-dihydrazothiazole derivatives, as well as a selected group of their transition metal chelate complexes [M2L], were inspected, and the data was evaluated in comparison to those of Ketoconazole and Gentamycin as antimicrobial control standards using the agar well diffusion assay protocol against a selected group of fungal and bacterial species. Several compounds displayed respectable to great antimicrobial behavior against the examined microbial species. Bis-dihydrazothiazole 6c, particularly, showed exceptional inhibition of both C. albicans and E. coli. However, bis-dihydrazothiazolone 9b showed excellent inhibition of A. fumigatus. Additionally, amongst the three synthesized metal complexes [M2L], only the zinc complex, [Zn2L] showed remarkable inhibition of both C. albicans and S. typhimurium and was even more potent than the free ligand, 9a itself.

Mechanochemical Cascade Synthesis of Zinc Complexes for Catalytic C–S Coupling in One-Pot

Mechanochemical Cascade Synthesis of Zinc Complexes for Catalytic C–S Coupling in One-Pot

Recent development of luminescent chemosensors for the recognition of nitroexplosives based on zinc(II) Schiff base complexes

In this review, we briefly summarize the key aspects of the synthetic strategies for zinc(II) Schiff base complexes, focusing on their photophysical properties such as the origin of luminescence, intensity, lifetime, and quantum yield. Additionally, we discuss the advantages of using luminescent zinc(II) complex-based sensors, the factors underlying their effectiveness as chemosensors for explosive detection, their mechanisms of action, and future outlooks and concerns. Most of the zinc(II) Schiff base complexes reported to date function as turn-off luminescent chemosensors for nitroexplosives. Some zinc(II) complexes discussed in this review demonstrate very high selectivity and sensitivity, with limits of detection (LOD) in the ppb or nM range for picric acid. Additionally, certain zinc(II) complexes can detect picric acid in the solid state through a visible color change observable to the naked eye under ambient light.

Enhanced Thermally Activated Delayed Fluorescence by Sole Coordination: From an Organic Molecule to Its Zinc Complex.

A BPAPTPyC organic molecule containing a sandwich structural chromophore is designed and synthesized to produce blue thermally activated delayed fluorescence (TADF). The chromophore is composed of two di(4-tert-butylphenyl)amino donors and one inserted terpyridyl acceptor hitched at positions 1, 8, and 9 of a single carbazole via the p-phenylene group, in which the multiple space π-π interactions between the donor and acceptor enable the molecule to possess the TADF feature with a high energy emission at 470 nm but a low photoluminescence quantum yield (PLQY) and a small proportion of the delayed component. In contrast, the corresponding Zn(BPAPTPyC)Cl2 complex has a high PLQY and a short lifetime with a red-shifted emission due to the enhanced rigidity and electron accepting ability of the terpyridyl group from coordination. A solution-processed organic light-emitting diode (OLED) based on the complex achieves a maximum external quantum efficiency (EQE) of 17.9% with an emission peak at 585 nm, while an OLED of the organic molecule produces blue emission with a maximum EQE of 2.7%.

Sustainable improvement of rice growth under salinity stress using an endophytic fungus-based biofertilizer

Salinity stress adversely affects rice (Oryza sativa L.) growth, development and overall productivity. Multiple strategies have been implemented to enhance the resilience of rice plants, enabling them to grow better in saline environments. Use of biofertilizers, a sustainable alternative to chemical fertilizers, has gained significant attention in modern agriculture due to their potential to improve soil fertility, enhance crop productivity, and mitigate environmental concerns. Biofertilizers encompass a diverse group of microorganisms, including bacteria, fungi, and algae, which interact with plants through various mechanisms. These beneficial microbes have been reported to convert atmospheric nitrogen into plant-available forms and break down insoluble phosphates and zinc complexes in the soil. Additionally, they can also produce growth regulators, enhance nutrient availability, and protect plants against pathogens. In our previous study, a salt-tolerant endophytic fungus isolated from the halophytic wild rice, Oryza coarctata, was identified as Aspergillus welwitschiae Ocstreb1 by whole genome sequence analysis. During the in-vitro experiments, the endophyte showed several plant growth promoting activities such as, zinc and phosphate solubilization, siderophore, IAA, and ACC-deaminase production, nitrogen fixation, etc. in both normal and 900 mM salt stress. In this study, the endophyte was used to formulate a biofertilizer in combination with talcum powder to enhance the growth and yield of rice plants under salinity stress. This research investigated the effectiveness of the biofertilizer in four distinct salinity tanks under both non-saline and 6 dS/m saline conditions, each containing three different varieties of rice. Treatment of BRRI dhan28 (BD-28), BRRI dhan67 (BD-67) and BRRI dhan87 (BD-87) rice plants with the formulated biofertilizer significantly enhanced their yield in both non-saline and saline conditions. Among the three rice varieties, BD-28 showed the highest significant (p<0.05) yield increase, with 104.20% under normal conditions and 3080.56% under salt stress. BD-67 exhibited a 45.15% increase in normal conditions and 153.64% under salt stress (P<0.05). BD-87 showed a significant yield increase only under salt stress, at 293.63% (p<0.05). From the results of the study, it can be proposed that the formulated biofertilizer is a potential eco-friendly and cost-effective solution to improve cultivation and yield of rice in the highly saline coastal regions of Bangladesh. Bioresearch Commu. 10(2): 1474-1481, 2024 (July)

Bioactive benzhydrazone derived Schiff base and its metal(II) complexes: Synthesis, characterisation, cytotoxicity, DNA binding/cleavage, antimicrobial and antioxidant activity

Bivalent mononuclear transition metal complexes of cobalt, nickel, copper and zinc were synthesized from (E)-2-(1-(2-(2-hydroxybenzoyl)hydrazono)ethoxy)benzoic acid. The FTIR, 1H NMR, 13C NMR, HR-Mass, UV–Vis., EPR, Powder XRD and SEM analysis were employed to investigate the structural features of synthesized compounds. The spectral data confirmed the square planar geometry of the complexes. The EPR spectra of the Cu(II) complex supported the proposed geometry. Powder X-ray diffraction (PXRD) analysis and scanning electron microscopy (SEM) imaging revealed that the complexes consist of nano-sized grains exhibiting a polycrystalline structure. The in vitro antimicrobial efficacy of the compounds was evaluated against various bacterial and fungal strains using the well diffusion method. The in vitro antibacterial activity demonstrated that all synthesized compounds were biologically active, and Zn(II) complex exhibited the highest inhibitory activity against S. aureus (gram-positive bacteria). For antioxidant activity, the free ligand and its metal chelates were evaluated using the standard DPPH method, revealing that the Co(II) complex displayed least inhibitory concentration value (IC50 = 16 ± 2.3 μg/mL) indicating the highest antioxidant activity. DNA interaction studies showed intercalation between complexes and DNA, and the Cu(II) complex exhibited a higher binding affinity of 2.78 ± 0.34 × 105 M−1. The DNA cleavage ability of the compounds was assessed using gel electrophoresis, demonstrating the effective cleavage of the pBR322 plasmid DNA. The Schiff base and its complexes were subjected to an anticancer evaluation against the human breast cancer cell line (MCF-7) using the MTT assay method. The percentage cell inhibition of the compounds was calculated.

Metal Complexes in Biology and Medicine: The System Cadmium (II)/ Iron (II)/ Zinc (II)- α- Aminobutyric Acid

Metal ions play an important role in biological systems. The importance of metal ions to essential functions of living systems and for wellbeing of living organisms is well known. Complexation reactions of α– aminobutyric acid with cadmium (II), iron (II) and zinc (II) have been studied in solution phase using paper ionophoretic technique. The present method is based upon the migration of a spot of metal ion on a paper strip at different pH values of background electrolyte containing 0.01M α -aminobutyric acid. A graph of pH against mobility was used to obtained information in the binary complexes and to calculate its stability constants. The logarithm stability constants of ML and ML2 complexes of α -aminobutyric acid were found to be (4.01 ± 0.02; 2.72 ± 0.01), (3.73 ± 0.03; 2.65 ± 0.09), (4.45 ± 0.02; 2.80 ± 0.03) for cadmium (II), iron (II) and zinc (II) complexes, respectively at ionic strength 0.1 molL-1 and a temperature of 35º C. Metal based drugs bioactivity can be increase by metal chelation, which in turn increase their absorbance and stability. Metal complexes can offer their action such as anti-inflammatory, anti-diabetic, antimicrobial, anticancer and ant thyroid compounds.

Novel tetraaza macrocyclic Schiff base complexes of bivalent zinc: microwave-assisted green synthesis, spectroscopic characterization, density functional theory calculations, molecular docking studies, in vitro antimicrobial and anticancer activities.

In the present manuscript, novel macrocyclic Schiff base complexes [Zn(N4MacL1)Cl2-Zn(N4MacL3)Cl2] were synthesized by the reaction of ZnCl2 and macrocyclic ligands (N4MacL1-N4MacL3) derived from diketone and diamines under microwave irradiation method and conventional method. The structures of the obtained complexes were identified by various spectrometric methods such as Fourier transformation infra-red (FT-IR), nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HR-MS), powder X-ray diffraction, molar conductivity, and UV-vis. The structures of the synthesized compounds were optimized by using the def2-TZV/J and def2-SVP/J Coulomb fitting basis sets at B3LYP level in density functional theory (DFT) calculations. The macrocyclic Schiff base complexes exhibited higher activities against Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus), Gram-negative bacteria (Escherichia coli and Xanthomonas campestris), and fungal strains (Fusarium oxysporum and Candida albicans) in comparison to macrocyclic Schiff base ligands. Furthermore, the newly synthesized macrocyclic compounds were assessed for their anticancer activity against three cell lines: A549 (human alveolar adenocarcinoma epithelial cell line), HT-29 (human colorectal adenocarcinoma cell line), and MCF-7 (human breast adenocarcinoma cell line) using the MTT assay. The obtained results showed that the macrocyclic complex [Zn(N4MacL3)Cl2] displayed the highest cytotoxic activity (2.23 ± 0.25µM, 6.53 ± 0.28µM, and 7.40 ± 0.45µM for A549, HT-29, and MCF-7 cancer cell lines, respectively). Additionally, molecular docking investigations were conducted to elucidate potential molecular interactions between the synthesized macrocyclic compounds and target proteins. The results revealed a consistent agreement between the docking calculations and the experimental data.

In Vitro Cytotoxicity of Zinc(II) Complexes: Synthesis, Characterization, and Biological Potential

In Vitro Cytotoxicity of Zinc(II) Complexes: Synthesis, Characterization, and Biological Potential

Hydrothermal syntheses, structures and properties of two zinc complexes based on an azobenzene carboxylate ligand

Abstract Two zinc complexes [Zn(LH)2(phen)] (1) and [Zn(L)(H2O)] n (2) (LH− = 2-hydroxy-5-((3-nitrophenyl)azo)-benzoate, phen = 1,10-phenanthroline) were synthesized by hydrothermal methods and characterized by elemental analysis and IR spectroscopy. Complexes 1 and 2 crystallize in mononuclear and polymeric structures, respectively, where ligands L 2− are coordinated to the zinc ions via their carboxylate and phenolate groups in η 2,μ 2,κ 2 and η 2,μ 2,κ 1 mode, respectively. Introduction of the auxiliary chelating phen ligand results in the chelation of the zinc ions in 1 through both the phen ligand and the carboxylate group of the first LH− anion assisted further by the monodentate carboxylate group of the second LH− anion. In complex 2 the L 2− anions act as tridentate ligands utilizing their carboxylate and phenolate groups to coordinate to three zinc ions. The phenolate oxygen atom bridges two zinc ions resulting in the generation of a layer structure. Fluorescence measurements have indicated that complexes 1 and 2 exhibit similar luminescence emissions around 393 and 387 nm, respectively, which originate from intra-ligand π-π* transitions. The emission intensities were strengthened relative to the sodium complex NaLH owing to the enhancement of the rigidity of the aromatic system through the coordination interactions of the ligands with the more tightly bound zinc ions. Furthermore, the suspension of complex 2 can be used to selectively detect Fe3+ cations via the luminescence quenching process.

Synthesis, structure and biological properties of the zinc(II) complexes with 5-(4-chlorophenyl)-1H-tetrazole and oligopyridine derivatives

In this work, we present six new zinc(II) complexes with the general formulas [Zn2(oligopyridine)2L4] and [Zn(oligopyridine)2L2], where L– = 5-(4-chlorophenyl)-1H-tetrazolate anion, and oligopyridine = 1,10-phenanthroline or 2,2′-bipyridine derivatives (dmphen – 4,7-dimethyl-1,10-phenanthroline, phen – 1,10 phenanthroline, dmbipy – 2,2′-bi-4-picoline, bipy – 2,2′-bipyridine), which have been synthesized with high yield and characterized by IR spectroscopy, elemental, thermogravimetric, single crystal and powder X-ray analyses. A distorted square-pyramidal and octahedral geometry of zinc(II) ion have been demonstrated by single crystal X-ray diffraction analysis. The tetrazolate ligand exhibits two types of coordination: monodentate, and bidentate-bridging via the N(2), N(3) or N(1), N(2) atoms. The behavior of all complexes in solution has been investigated by UV–Vis and the 1H, 13C NMR spectroscopy, conductometry, and mass spectrometry. The antimicrobial study of the compounds has been carried out against E. coli, St. aureus, P. italicum, and C. steinii, and [Zn2(dmbipy)2L4] has been shown to possess significant protistocidal properties. According to the cytotoxicity study,all complexes don’t have cytotoxic properties in 1–100 µM concentration range against tumor human cell lines (larynx carcinoma Hep2, hepatocellular carcinoma HepG2 and breast adenocarcinoma MCF-7) with the exception of complex 5 which has displayed significant cytotoxic effect (LC50 = 19.8 ± 2.4 μM) against Hep2 cells. However, obtained compounds have a pronounced cytostatic effect on all tumor cell lines.

Ferromagnetic ZnO nanostructures from an organo zinc complex formulated via Piper Longum L-assisted green synthesis: Multifaceted prospects in photocatalysis, antimicrobial activity, and cell viability studies

Transition metal oxides like ZnO nanostructures are pivotal in various scientific and technological fields due to their chemical stability, high electrochemical coupling efficiency, and broad radiation absorption spectrum. This study offers an in-depth examination of ZnO nanostructures synthesized via the green route using Piper Longum L, emphasizing their photocatalytic efficacy in degrading organic pollutants such as Sulphanilamide and Chromium. The ZnO nanostructures with a rod-like morphology exhibited an average crystallite size of 26 nm and an optical bandgap of 2.8 eV. Solid state structure of ZnO was investigated by Fourier Transform Infrared spectroscopy (FTIR) and X-Ray Diffraction (XRD). Zinc in the synthesized organo zinc complex and zinc oxide was estimated to 324.325 and 133.02 ppm, respectively. The saturation magnetization obtained from Superconducting Quantum Interference Device-Vibrating Sample Magnetometer (SQUID-VSM) for organo zinc complex and ZnO is 2.1 × 10−3 and 1.7 × 10−3 emu/g, respectively. These nanostructures achieved 99 and 93 % degradation of chromium (VI) ions present in solutions of two different concentrations in about 30 and 80 min, respectively, under UV and visible radiation, a remarkable achievement. Almost the same efficiency was maintained during three consecutive runs and then deactivation of the catalyst was observed. Additionally, a rapid 84 % degradation of Sulphanilamide was observed in 42 min, underscoring the potential of ZnO nanostructures as efficient photocatalysts for environmental remediation.

Design amino acids Schiff base ligands and their Cu(II) and Zn(II) complexes as potent anticancer agent on human lung carcinoma, efficient CT-DNA binder, antibacterial and mesomorphic properties

A new mesogenic amino acid Schiff base ligands of the type Potassium (E)-4-((4-(hexadecyloxy)-2-hydroxybenzylidene)amino)butanoate (HL1) and Potassium (E)-6-((4-(hexadecyloxy)-2-hydroxybenzylidene)amino)hexanoate (HL2) and their copper(II) and zinc(II) complexes have been successfully synthesized and characterized by various elemental analyses, UV–visible, FT-IR, 1HNMR , 13CNMR , ESI-MS and thermogravimetric analysis (TGA). Both the ligands were found to exhibit mesophase with multiple textures as revealed from the polarizing optical microscope (POM) and differential scanning calorimetry (DSC). The metal complexes were found to exhibit efficient CT-DNA interaction and antibacterial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli). The complexes were assessed for their in-vitro anticancer efficacy against A549 cell line and findings indicate notable cytotoxicity effect which is comparable to that of standard drug, cisplatin. The Density Functional Theory (DFT) study of the compounds was carried out by using LanL2DZ and 6–31 G (d, p) basis set with meta-hybrid Truhlar's functional M06–2X in order to obtain the optimized geometry.

Structural characterizations of histidine-containing tripeptides complexed with zinc and cadmium dications using IRMPD spectroscopy and theoretical calculations

Metalated gas-phase complexes, M2+(HisAlaAla), M2+(AlaHisAla), and M2+(AlaAlaHis), where M = Zn and Cd, were examined using infrared multiple photon dissociation (IRMPD) spectroscopy with light from a free-electron laser (FEL). These complexes were chosen because they provide model systems for metal binding to proteins. Complementary simulated annealing calculations were performed to determine energetically low-lying conformers and isomers of these structures. Quantum chemical calculations were used to optimize the structures at the B3LYP level of theory using 6-311+G(d,p) and def2-TZVP basis sets for zinc and cadmium complexes, respectively. IRMPD and calculated linear absorption spectra were compared to evaluate which structures are present. Relative energies of the various species were evaluated using single-point energy calculations for low-lying structures at the B3LYP, B3P86, and MP2(full) levels using 6-311+G(2d,2p) and def2-TZVPP basis sets. For species with histidine at a terminal position (AAH or HAA), the conformations that best reproduce the IRMPD spectra are charge-solvated (CS) conformers, where the metal dication binds to the amine and carbonyl groups of the peptide backbone and to the nitrogen of the histidine side chain, along with contributions from an iminol structure for AAH. The species with the histidine in the center position (AHA) adopt an iminol structure, where the metal dication binds to the backbone iminol nitrogens, the α-amine, π-imine, and the carbonyl of the C-terminus.