Complexes Of Hydrazones Research Articles

Unveiling the bioactive potential of organotin(IV) complexes of hydrazones: Synthesis, spectral characterization, in vitro and in silico exploration

In the quest of compounds with potent antimicrobial and antioxidant properties, we conducted a comprehensive investigation involving four hydrazone ligands [H2L1–4] (1–4) and their respective sixteen organotin(IV) complexes (5–20) with general formula R″2SnL1–4 [R″ = Me, Et, Bu, Ph]. Various spectroscopic and physicochemical studies were employed for the thorough characterization of the synthesized compounds, which demonstrated the tridentate chelation of ligands via ONO donor domains by Ophenolic, Nazomethine and Oenolic atoms displaying pentacoordinated geometry. Further, the compounds were subjected to bioactivity assays by targeting their in vitro antioxidant and antimicrobial studies. Complex 8 [Ph2SnL1], 12 [Ph2SnL2], 16 [Ph2SnL3], 19 [Bu2SnL4] and 20 [Ph2SnL4] emerged as particularly noteworthy antimicrobials, exhibiting a higher level of inhibition having minimum inhibition concentration (MIC) value in the range of 0.0042–0.0095 µmol/mL. Among them, complex 20 exhibited superior activity with MIC values of 0.0042 µmol/mL against C. albicans and S. aureus, surpassing the standard drugs ciprofloxacin (0.0047 µmol/mL) and fluconazole (0.0051 µmol/mL). Additionally, all the compounds showed notable radical scavenging activity, and the activity of complexes increases in the order Ph2SnL1−4 (1.93–3.68 µM) > Bu2SnL1−4 (2.26–4.15 µM) > Et2SnL1−4 (2.91–4.97 µM) > Me2SnL1−4 (3.49–5.10 µM) (DPPH assay). Furthermore, In silico studies including Molecular docking, Density Functional Theory (DFT), Molecular Electrostatic Potential (MESP), Absorption, Distribution, Metabolism, Excretion and Toxicity ADMET) analysis highlighted the significance of highly potent antimicrobial compounds (4, 17–20) as potential drug candidates. Each compound exhibited binding affinity with protein binding site, including carbon-hydrogen bonds, conventional hydrogen bonds, alkyl interactions and pi-alkyl interactions. Compound 20 exhibited a superior docking score of −137.644 kcal/mol at the active site of C. albicans (PDB ID: 4HOE). The binding energy of the compounds followed the order: 20 (−11.6577 eV) < 19 (−11.3193 eV) < 18 (−9.23989 eV) < 17 (−8.23386 eV) < 4 (−7.01131 eV) and coincided well with the findings of experimental research. In summary, this comprehensive research underscores the substantial biological activity of the synthesized compounds and their promising potential for future applications in drug development.

Transition metal complexes of hydrazones as potential antimicrobial and anticancer agents: A short review.

Hydrazones display an interesting profile of biological activities, which includes mainly antimicrobial and antiproliferative properties. Hydrazones also play an important role in the synthesis of heterocyclic rings and in coordination chemistry. Currently, the synthesis of complexes of hydrazones with transition metals is quite frequently reported in the scientific literature. The interest in this topic is largely due to diverse biological activities of the metal complexes of hydrazones that in some cases are much more effective than hydrazones themselves. This review focuses on the complexes of hydrazones with transition metals which display antibacterial, antitubercular, antifungal and anticancer activities. In the following subchapters devoted to a given activity, an attempt has been made to present the most active complexes of hydrazones, their trends in their activity and application in medicinal chemistry. The paper presents the literature data from 2009 to 2023. This review constitutes a useful guide for the researchers who intend to synthesize and investigate complexes of hydrazones in terms of their antimicrobial and anticancer activities.

Moderate DNA and high SARS-CoV-2 spike protein affinity of oxidovanadium(IV) complexes of 2-furoic acid hydrazones: In silico and in vitro approach

The interaction of five neutral heteroleptic octahedral paramagnetic mononuclear oxidovanadium(IV) complexes of general composition [VIVO(bpy)L], where L is a dianionic tridentate ONO-donor hydrazone ligand derived from 2-furoic acid hydrazide and salicylaldehyde and its 5-substituted derivatives with spike protein SARS-CoV-2 was investigated in silico and in vitro. Molecular docking indicates that the complexes have high affinity for SARS-CoV-2 spike protein binding, and that the complex with a nitro substituent on the salicylaldehyde component of the hydrazone ligand has the highest binding potential. The interaction of this complex was examined by spectrofluorimetry utilizing spectrofluorimetric titration, thermodynamic measurements and FRET analysis. The results suggest van der Walls forces and hydrogen bonding as the dominant modes of interaction of the complex with the SARS-CoV-2 spike protein, which is in agreement with theoretical predictions. Molecular docking was further employed to investigate the interaction of vanadium complexes with SARS-CoV-2 omicron variant (BA.1) RBD with human ACE2 protein. The interaction of the complex with CT DNA was investigated using electron spectroscopy and thermodynamic considerations. The complexes showed a moderate affinity for DNA as groove binders. The groove binding was confirmed by molecular docking with B-DNA. Also, druglikness properties of complexes were assessed by SwissADME. The strong antioxidant activity of the complexes, comparable to ascorbic acid, was evaluated by the DPPH method. This is the first experimental research that supports the thesis of molecular docking that vanadium compounds could be druggable against SARS-CoV-2 virus proteins.

Geometry and UV-Vis Spectra of Au3+ Complexes with Hydrazones Derived from Pyridoxal 5'-Phosphate: A DFT Study.

Gold(III) complexes with different ligands can provide researchers with a measure against pathogenic microorganisms with antibiotic resistance. We reported in our previous paper that the UV-Vis spectra of different protonated species of complexes formed by gold(III) and five hydrazones derived from pyridoxal 5'-phosphate are similar to each other and to the spectra of free protonated hydrazones. The present paper focuses on the reasons of the noted similarity in electron absorption spectra. The geometry of different protonated species of complexes of gold(III) and hydrazones (15 structures in total) was optimized using the density functional theory (DFT). The coordination polyhedron of gold(III) bond critical points were further studied to identify the symmetry of the gold coordination sphere and the type of interactions that hold the complex together. The UV-Vis spectra were calculated using TD DFT methods. The molecular orbitals were analyzed to interpret the calculated spectra.

Vanadium(IV) complexes of salicylaldehyde-based furoic acid hydrazones: Synthesis, BSA binding and in vivo antidiabetic potential

Solution synthesis afforded five novel neutral heteroleptic octahedral paramagnetic mononuclear oxidovanadium(IV) complexes of general composition [VO(bpy)L], where L is a dianionic tridentate ONO-donor hydrazone ligand derived from 2-furoic acid hydrazide and salicylaldehyde and its 5-substituted derivatives. Characterization was carried out by elemental analysis, mass spectrometry, infrared, electron, NMR, and EPR spectroscopy, cyclic voltammetry and conductometry. The molecular and crystal structure of the complex with 5-chloro-salicylaldehyde 2-furoic acid hydrazone (2) was determined. The quantum chemical properties of the vanadium complexes were studied at B3LYP and M062X levels with the lanl2dz basis set using Gaussian. Additionally, Swiss-ADME analysis was performed and complex (4), featuring a 5-nitro substituent on the hydrazone ligand, was selected for further investigation. The effects of the in vivo application of the complex on selected biochemical parameters in healthy and diabetic Wistar rats were investigated. Strong antidiabetic effect associated with moderate hypoalbuminemia was observed. Furthermore, the interaction of complexes with BSA was studied by spectrofluorimetry. A significant conformational change of BSA in the presence of vanadium complexes was found. Synchronous fluorescence spectra revealed significant changes in the tyrosine microenvironment of BSA. The FRET analysis was also used and the non-radiative process of energy transfer is elucidated. Thermodynamic data suggest van der Waals forces and hydrogen bonding as predominant binding modes of complexes to BSA.

Interaction of Copper(II) Complexes of Bidentate Benzaldehyde Nicotinic Acid Hydrazones with BSA: Spectrofluorimetric and Molecular Docking Approach.

Two copper(II) complexes of 4-chloro- and 4-dimethylaminobenzaldehyde nicotinic acid hydrazones were prepared and characterized by elemental analysis, mass spectrometry, infrared and electron spectroscopy and conductometry. These rare examples of bis(hydrazonato)copper(II) complexes are neutral complex species with copper(II) center coordinated with two monoanionic bidentate O,N-donor hydrazone ligands coordinated in enol-imine form. The interaction of hydrazone ligands and corresponding copper(II) complexes with CT DNA and BSA was investigated. Copper(II) complexes are slightly effective in binding the DNA than pristine hydrazones. The results indicate groove binding or moderate intercalation which are not significantly affected by the nature of substituent at hydrazone ligands. On contrary, affinities of two copper(II) complexes toward BSA significantly differs and depends on the nature of the substituent, however in absence of thermodynamic data difference in nature of binding forces cannot be excluded. The complex bearing electron-withdrawing 4-chloro substituent has larger affinity toward BSA compared to 4-dimethyamino analogue. These findings were theoretically supported by molecular docking study.

Research Progress on the Biological Activities of Metal Complexes Bearing Polycyclic Aromatic Hydrazones

Due to the abundant and promising biological activities of aromatic hydrazones, it is of great significance to study the biological activities of their metal complexes for the research and development of metal-based drugs. In this review, we focus on the metal complexes of polycyclic aromatic hydrazones, which still do not receive much attention, and summarize the studies related to their biological activities. Although the large number of metal complexes in phenylhydrazone prevent them all from being summarized, the significant value of polycyclic aromatic hydrocarbons themselves (such as naphthalene and anthracene) as pharmacophores are also considered. Therefore, the bioactivities of the metal complexes of naphthylhydrazone and anthrahydrazone are focused on, and the recent research progress on the metal complexes of anthrahydrazone by the authors is also included. In terms of biological activities, these complexes mainly show antibacterial and anticancer activities, along with less bioactivities. The present review demonstrates that the structural design and bioactivities of these complexes are fundamental, which also indicates a certain structure-activity relationship (SAR) in some substructural areas. However, a systematic and comprehensive conclusion of the SAR is still not available, which suggests that more attention should be paid to the bioactivities of the metal complexes of polycyclic aromatic hydrazones since their potential in structural design and biological activity remains to be explored. We hope that this review will attract more researchers to devote their interest and energy into this promising area.

Copper(II) Complexes of a New Hydrazones with Aliphatic Groups: Synthesis, Characterisation and Nuclease Activity

Two new copper(II) complexes of bidentate arylhydrazone ligands have prepared and studied. Elemental analysis, SEM-EDS, thermal gravimetric analysis (TGA), powder X-ray diffraction (XRD), and a number of spectroscopic techniques were used to determine the structures of the compounds (FTIR, UV-Vis, 1H and 13C-NMR). Using agarose gel electrophoresis, the DNA cleavage activities of the produced copper complexes were investigated in the absence and presence of hydrogen peroxide. It was also investigated the influence of compound dose on the DNA cleavage process. The results show that in the presence of an oxidant agent, all of the complexes break pBR322 DNA. At the concentration of 10 µM, [Cu(L1)2] converted the supercoil DNA into two forms, while [Cu(L1)2] formed only the nicked form. The mechanistic analyses show that the active oxidative species for DNA breakage is a species generated by hydrogen peroxide and the copper(II) metal. The compounds also cleaveged pBR322 DNA in the absence of H2O2, marginally.

Cu(II), Mn(II) and Zn(II) complexes of hydrazones with a quaternary ammonium moiety: synthesis, experimental and theoretical characterization and cytotoxic activity.

In this paper, Cu(II), Mn(II) and Zn(II) complexes with N,N,N-trimethyl-2-oxo-2-(2-(1-(thiazol-2-yl)ethylidene)hydrazinyl)ethan-1-aminium chloride (HL1Cl) were synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis and DFT calculations. In all three complexes, a ligand (L1) is coordinated in a deprotonated formally neutral zwitterionic form via NNO donor set atoms. Cu(II) and Zn(II) form mononuclear penta-coordinated complexes [CuL1(N3)(CH3OH)]BF4 and [ZnL1(N3)2], respectively, while Mn(II) forms a binuclear [Mn2L12(μ-1,1-N3)2(N3)2]·2CH3OH complex, with unusual distorted trigonal-prismatic geometry around the metal centers. The antimicrobial activity of these complexes was tested against a panel of Gram-negative and Gram-positive bacteria, two yeasts and one fungal strain. The binuclear Mn(II) complex showed antifungal activity of similar intensity to amphotericin B. Based on the results of the brine shrimp test and DPPH radical scavenging activity, the most active Cu(II) and Mn(II) complexes were selected for evaluation of cytotoxic activity against five malignant cancer cell lines (HeLa, A375, MCF7, PC-3 and A549) and one normal cell line HaCaT. Both complexes showed significant activity. It should be pointed out that the activity of the Mn(II) complex against the MCF7 breast cancer cell line is only slightly weaker than that of cisplatin, but with selectivity to the tumor cell line in comparison to normal HaCaT cells, which is non-existent in the case of cisplatin.

Transition metal (II) complexes of hydrazones derived from tetralone: synthesis, spectral characterization, in vitro antimicrobial and cytotoxic studies

A series of transition metal (II) complexes with general formula [M(L1−4)2(H2O)2] (where M = Co(II), Ni(II), Cu(II) and Zn(II)) was synthesized by the reaction of metal(II) acetates with hydrazones [HL1–HL4] obtained from condensation of tetralone with hydrazide derivatives. The characterization of synthesized compounds (1–20) was done by using elemental analysis, different spectral studies (UV–Vis, 1H NMR, 13C NMR, FT-IR, mass, ESR and fluorescence), magnetic susceptibility, molar conductance measurement and thermal (DTA, TGA and DTG) analysis. The characterization results suggested the bidentate nature of the hydrazones, which chelate with the metal ion via nitrogen of (C=N) group and deprotonated carbonyl oxygen in the enolized form, resulting in stable, non-volatile octahedral complexes. The antimicrobial potential of the compounds was evaluated against four bacterial, i.e. (S. aureus, B. subtilis, P. aeruginosa and E. coli), and two fungal species, i.e. (A. niger and C. albicans), by a serial dilution method with complexes 15 and 16 as most active compounds against microbes. All the compounds were also tested for its cytotoxicity (in vitro) against three human cancer cell lines (A549, HeLa and MCF-7) and one normal cell line (L6) by the MTT assay, which focussed on an increased activity of compounds 7 and 15 towards A549, MCF-7 and HeLa cancer cell line with IC50 values ranging from 10.76 to 16.42 μg/mL, and compounds were found to be non-toxic towards L6 cell line as compared to the standard drug doxorubicin. The results demonstrated that complexation enhanced the biological activity of compounds. The synthesized compounds (1–20) were screened for antitumor activities against A549, MCF7, Hela cancer cell lines. Copper complex (7) and (15) was found to be the most active antitumor agent and less toxic against L6—Rat myoblast normal cell line than standard doxorubicin.

Designing, spectroscopic characterization, biological screening and antioxidant activity of mononuclear transition metal complexes of bidentate Schiff base hydrazones

In this article, a series of coordination complexes of Co(II), Ni(II), Cu(II) and Zn(II) metals were prepared by four novel Schiff base ligands (E)-N’-(4-(prop-2-yn-1-yloxy)benzylidene)benzohydrazide (HL1), (E)-4-chloro-N’-(4-(prop-2-yn-1-yloxy)benzylidene)benzohydrazide (HL2), (E)-N’-((2-(benzyloxy)naphthalen-1-yl)methylene)benzohydrazide (HL3), (E)-N’-((2-(benzyloxy)naphthalen-1-yl)methylene)-4-chlorobenzohydrazide (HL4) obtained by the condensation reaction of benzoic acid hydrazide/4-chloro benzoic acid hydrazide with oxy derivatives of 2-hydroxy-1-napthaldehyde/4-hydroxy benzaldehyde. The proposed structure of the complexes have been established by spectroscopic and analytical techniques like C, H, N and metal analysis, FT-IR, 1H and 13C NMR, mass, UV-Vis, EPR, fluorescence, molar conductance, magnetic susceptibility and TGA which concluded that Schiff bases act as bidentate NO donor ligands coordinating through nitrogen atom of azomethine linkage and uninegative oxygen atom of carbonyl group in enolic form and resulting in complexes of the type [M(L1–4)·(CH3COO)·3H2O] in 1:1 molar ratio. The synthesized compounds were screened for their in vitro antimicrobial activities against two gram +ve bacteria i.e. S. aureus and S. gordonii; two gram -ve bacteria i.e. E. coli and P. aeruginosa and two fungal strains i.e. A. niger and C. albicans and found that metal chelates were more noxious than their parent Schiff bases. The copper(II) complex 19 was found to be the highest noxious antimicrobial active compound. The compounds were also assessed for their antioxidant activity and found that the complexes are more potent and show excellent efficiency in decolorizing the DPPH purple colored solution than their free ligands. The complexes 6, 7, 10, 11, 14, 15, 18, 19 were found to be excellent antioxidants and copper(II) complexes were the most potent antioxidant compounds with lowest IC50 values (2.04–2.56 µM)) among all the tested compounds. Total 20 compounds of Schiff bases transition metal complexes were synthesized and characterized. The copper complex (19) was found to be highest antimicrobial against Streptococcus gordonii, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Aspergillus niger, Candida albicans. The copper(II) complex (11) exhibits outstanding and highest antioxidant activity (IC50 = 2.04 µM).

Cu(II) complexes of hydrazones–NSAID conjugates: synthesis, characterization and anticancer activity

The hydrazones of nonsteroidal anti-inflammatory drugs (NSAIDs) diclofenac and ibuprofen are synthesized with aldehydes of pyridine and imidazole and are characterized by 1H, 13C and mass spectroscopy. Cu(II) complexes of hydrazones constructed from these ligands possess square planar geometry for bidentate diclofenac-hydrazone and tridentate ibuprofen-hydrazone conjugates with [Cu(L)2] and [Cu(L)Cl] compositions, respectively. The observed irreversible Cu(II)/Cu(I) redox couple in the range of +0.20 to +0.61 V is due to the substantial distortion in the square-planar geometry. ESR studies indicate the appreciably covalent character within M–L bonding due to extensive delocalization of electron from d x 2 –- y 2 orbital. The hydrazone–NSAID conjugates exhibit substantial cytotoxicity against A-549, HCT-116 and MDA-MB-231 cancer cell lines with ibuprofen-imidazole-hydrazone ligand possessing the lowest IC50 (2.26 µM) amongst the synthesized NSAID-conjugates. Interestingly, its Cu(II) complex also displays excellent anticancer activity against MDA-MB- 231 with IC50 value of 3.58 µM. Such a feature may be ascribed to the synergistic association of Cu(II)–NSAID–hydrazone linkage. Thus, conjugation of NSAID with hydrazone and its complexation with a bioactive metal ion may be regarded as a potential strategy for designing of non-platinum anticancer agents.

Antimycobacterial Activities of Ruthenium(II) Complexes of Hydroxyl Flavone Hydrazones

The Ru(II) complexes of hydrazine derivatives of different 3-hydroxy 4-substituted flavones was synthesized to assess their biological activity. The ligand 2, 4 dinitrophenyl hydrazones of 3-hydroxy 4´-substituted flavones [where 4´-substituents are -OCH3(HL1), -NO2(HL2), NMe2(HL3), Cl (HL4), OCH2Ph (HL5)] were successfully coordinated with Ru(phen)2Cl2 which consists of the formula, [Ru(phen)2(HL1)]Cl2.2.5H2O (M1R), [Ru(phen)2(HL2)]Cl2(M2R), [Ru(phen)2(HL3)]Cl2(M3R), [Ru(phen)2(HL4)]Cl2.1.5H2O (M4R), [Ru(phen)2(HL5)]Cl2.1.5H2O (M5R). All the synthesized complexes were characterized by elemental analysis, IR, 1H-NMR, UV-Vis, and ESI-MS spectroscopic techniques. The geometry optimization of all complexes was carried by using Gaussian-09. All compounds were studied for antimycobacterial activity using Resazurin microtiter plate assay (REMA) followed by colony-forming unit (CFU) count. The metal complexes showed promising activity against M. smegmatis mc2. The DNA interaction of the complexes was also studied. These studies suggest that hydrazine derivatives of 3-hydroxy 4-substituted flavones and their Ru(II) complexes can be good candidates for antimycobacterial drug development studies.

Iron Complexes of an Antiproliferative Aroyl Hydrazone: Characterization of Three Protonation States by Electron Paramagnetic Resonance Methods.

Tridentate aroyl hydrazones are effective metal chelators in biological settings, and their activity has been investigated extensively for medicinal applications in metal overload, cancer, and neurodegenerative diseases. The aroyl hydrazone motif is found in the recently reported prochelator (AH1-S)2, which has shown antiproliferative proapoptotic activity in mammalian cancer cell lines. Intracellular reduction of this disulfide prochelator leads to the formation of mercaptobenzaldehyde benzoylhydrazone chelator AH1 and to iron sequestration, which in turn impacts cell growth. Herein, we investigate the iron coordination chemistry of AH1 to determine the structural and spectroscopic properties of the iron complexes in the solid state and in solution. A neutral iron(III) complex of 2:1 ligand-to-metal stoichiometry was isolated and characterized fully to reveal two different binding modes for the tridentate AH1 ligand. Specifically, one ligand binds in the monoanionic keto form, whereas the other ligand coordinates as a dianionic enolate. Continuous-wave electron paramagnetic resonance experiments in frozen solutions indicated that this neutral complex is one of three low-spin iron(III) complexes observed depending on the pH of the solution. Electron spin echo envelope modulation (ESEEM) experiments allowed assignment of the three species to different protonation states of the coordinated ligands. Our ESEEM analysis provides a method to distinguish the coordination of aroyl hydrazones in the keto and enolate forms, which influences both the ligand field and overall charge of the complex. As such, this type of analysis could provide valuable information in a variety of studies of iron complexes of aroyl hydrazones, ranging from the investigation of spin-crossover behavior to tracking of their distribution in biological samples.

Probing 2-acetylbenzofuran hydrazones and their metal complexes as α-glucosidase inhibitors

Inhibition of α-glucosidase is one of the important approaches in designing antidiabetic drugs for its role in decrease of the carbohydrates digestion to avoid post-prandial increase in blood sugar levels in diabetic patients. In the present study we designed a novel series of 2-acetylbenzofuran hydrazones (L1-L7) and their metal (II) complexes Cu (II), Co (II), Zn (II) and Mn (II) (8–29) and screened for inhibitory activity against the yeast α-glucosidase. The synthesis of hydrazones incorporated the use of I2 as a catalyst which resulted in excellent yield of 94%. The ligand L3, showed good activity (IC50 = 47.51 ± 0.86 µM) while its metal complex (10) showed potent activity (IC50 = 1.15 ± 0.001 µM) compared to reference acarbose IC50 = 378.25 ± 0.12 µM. Similarly, the Cu (II) complexes with ligands L5 and L6 showed excellent α-glucosidase inhibition (IC50 = 0.15 ± 0.003 12 and 0.21 ± 0.002 µM for 13, respectively) whereas, the metal complexes of Co (II), Mn (II), and Zn (II) showed moderate to poor inhibitory activities against α-glucosidase. The The findings are supported by the ligands and enzyme interactions through molecular docking studies. In conclusion, it is indicated that metal complexes of 2-acetylbenzofuran hydrazones have good potential for research leading to antidiabetic therapies.

Spectral Studies and Antibacterial Activity of Vanadium(III) Complexes of Heterocyclic Hydrazones

Vanadium(III) complexes having the composition VLCl3 [where L = 2-acetylpyridine acetoylhydrazone (APAH), 2-acetylpyridine benzoylhydrazone (APBH), 2-acetylthiophene acetoylhydrazone (ATAH) and 2-acetylthiophene benzoylhydrazone (ATBH)] have been investigated using physico-chemical and analytical techniques. Molar conductivity data suggested that the complexes are neutral. Structures of all the vanadium(III) complexes are determined based on infrared and UV-visible spectral data. Electronic spectra of vanadium(III) complexes show three peaks suggesting octahedral structure. Comparison of vibrational spectra of hydrazones and complexes suggest that the hydrazones act as neutral tridentate ligands. The ligands and their vanadium derivatives are screened for their bacteria destroying activity against pathogenic bacterial strains viz. Gram-negative E. coli, Gram-positive Bacillus, Gram-positive Staphylococcus aureus and Gram-negative P. aureoginosa. Bacteria destroying activities of present complexes are comparable to the activity of the streptomycin. Complexes show more activity than their respective ligands in the case of Gram-positive Bacillus and Gram-negative P. aureoginosa.

INFLUENCE OF NICOTINOYLHYDRAZONES AND Ge(IV) AND Sn(IV) COMPLEXES BASED ON THEM ON THE GROWTH OF PHYTOPATHOGENIC FUNGI

Aim. To evaluate the influence of nicotinoylhydrazones with different molecule structure and complexes of Ge(IV) and Sn(IV) based on them on the growth of phytopathogenic fungi. Меthods. 2-hydroxy-1-naphthaldehyde nicotinoylhydrazone and 2-hydroxybenzaldehyde nicotinoylhydrazone and corresponding complexes of Ge(IV) and Sn(IV) were used in the study. Antifungal activity of studied compounds towards phytopathogenic fungi Alternaria alternata (Fr.) Keissl. F11, Botrytis cinerea Pers. F12, Pyrenophora teres Drechsler F13, Fusarium graminearum Schwabe F14, Ceratorhiza cerealis (E.P. Hoeven) R.T. Moore F15, Sclerotinia sclerotiorum (Lib.) de Bary F16 was evaluated by measurement of fungal colony diameter on the 3rd, 7th and 10th day of cultivation, and also by serial dilution method in Sabouraud broth (range of concentrations – from 25 to 100 µM). Results. Evaluation of fungal colony diameters demonstrated that studied compounds at the concentration 25 µM were able to cause significant decrease (by 17–54% compared to control) of growth of pathogen colonies. Also, mycelium development disorders were observed in Sabouraud broth at the presence of 15, 50 and 100 µM of hydrazones and metal-complexes. The most susceptible was C. cerealis F15, which growth was significantly (from 31.8 to 54.6%) inhibited by all the compounds at the concentration 25 µM, and also S. sclerotiorum (5 compounds) and A. alternata – 4 of 6 compounds. The complexes of hydrazones with tin and germanium showed more significant activity and wider antifungal spectrum compared to hydrazones they are based on. Conclusion. Studied hydrazones and based on them complexes of Ge(IV) and Sn(IV) inhibit the growth of phytopathogenic fungi which belong to both ascomycetes (Alternaria alternata, Sclerotinia sclerotiorum) and basidiomycetes (Ceratorhiza cerealis).

Synthesis, structures and magnetic properties of octahedral Co(III) complexes of heteroaromatic hydrazones with tetraisothiocyanato Co(II) anions

Octahedral Co(III) complexes with heteroaromatic hydrazones ((E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-aminium chloride and (E)-2-(1-(thiazol-2-yl)ethylidene)hydrazine-1-carbothioamide) and tetraisothiocyanato Co(II) complex anions have been synthesized, characterized by elemental analysis, IR and NMR spectroscopy, single-crystal X-ray diffraction and magnetic measurements. NMR spectroscopy showed that octahedral Co(III) complex cations of both compounds are stable in DMSO solution. Measured effective magnetic moments, which completely originates from complex anion [Co(NCS)4]2– are practically constant and very close to the expected value for Co2+ ion with spin S = 3/2 and completely quenched orbital angular momentum. Co(III) ions in octahedral complex cations are in a low spin magnetic state with S = 0 and do not contribute to the magnetic signal.

Synthesis, Characterization, DNA Binding and Nuclease Activity of Cobalt(II) Complexes of Isonicotinoyl Hydrazones

Cobalt(II) complexes of isonicotinoyl hydrazones of two series of ligands have been synthesized and characterized on the basis of elemental analyses, molar conductance, magnetic moment, mass, IR, UV spectral data. Electrochemical behavior of ligands and complexes has been investigated by using cyclic voltammetry. Cyclic voltammetric studies reveal that the oxidation/reduction potentials of all complexes are shifted towards positive or negative values than its corresponding ligands. The interactions of these complexes with calf thymus DNA have been studied by using absorption studies. Bathochromic shift and hypochromism suggest that the intercalative mode of binding of complexes with DNA. Their DNA cleavage activity of complexes was studied on double-stranded pBR322 plasmid DNA using gel electrophoresis experiments in the absence and presence of oxidant (H2O2) and reductant (DTT).

ZnII complexes of (1,3-thiazol-2-yl)hydrazones as potential pharmacological agents

Zn^II complexes of (1,3-thiazol-2-yl)hydrazones as potential pharmacological agents