Synthesis, spectroscopic, thermal and antimicrobial studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes with Schiff base derived from 4-amino-3-mercapto-6-methyl-5-oxo-1,2,4-triazine

Coordination complexes of Co(II), Ni(II), Cu(II) and Zn(II) with Schiff base derived from syringaldehyde and 4-amino-3-mercapto-6-methyl-5-oxo-1,2,4-triazine have been synthesized. These complexes have been characterized by elemental analysis, magnetic moment, spectroscopic (IR, Electronic, ¹H NMR, ESR) and thermogravimetric analysis. Magnetic and spectral data suggest octahedral geometry for Co(II), Ni(II) and Zn(II) complexes and square planar for Cu(II) complexes. The presence of coordinated water in metal complexes was confirmed by thermal and IR data. The Schiff base and its metal complexes have been screened for antibacterial (Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli, Staphylococcus aureus) and antifungal activities (Aspergillus niger, A. flavus). A comparison is made between activities of complexes with Schiff base and with the standard antibiotics.     

DNA cleavage and antimicrobial investigation of Co(II), Ni(II), and Cu(II) complexes with triazole Schiff bases: synthesis and spectral characterization

The Co(II), Ni(II), and Cu(II) complexes with Schiff bases derived from 3-substituted-4-amino-5-mercapto-1,2,4-triazole and fluvastatin have been synthesized. Schiff bases exhibited thiol–thione tautomerism and coordinated to metal ion through azomethine nitrogen and thiolate sulphur atoms. Square planar geometry for all the metal complexes of the type ML₂ has been proposed in the light of analytical, spectral (IR, UV–Vis., ESR, and FAB-mass), magnetic, and thermal studies. The antimicrobial studies of Schiff bases and their metal complexes against various antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis) and antifungal (Aspergillus niger, and Pencillium Chrysogenum) species by Minimum Inhibitory Concentration method revealed that, the metal complexes possess more healing antibacterial activity than the Schiff bases. Co(II), Ni(II), and Cu(II) complexes cleave the DNA isolated from A. niger.     

Spectroscopic,antiproliferative and antiradical properties of Cu(II), Ni(II), and Zn(II) complexes with amino acid based Schiff bases

Novel six Cu(II), Ni(II), and Zn(II) complexes with Schiff bases derived from 4-aminobenzoic acid with terephtaldehyde and amino acids (glycine, β-alanine). Structures have been proposed from elemental analysis, UV–Vis, IR, NMR, TGA, DTA, and magnetic measurements. Spectroscopic studies suggest that coordination occurs through azomethine nitrogen, hydroxyl group, and carbonyl oxygen of the ligands to the metal ions. The elemental analyses of the complexes where L is Schiff base ligands, are confined to the stoichiometry of the type M₂L₂(CH₃COO)₂ [M = Cu(II)]; and M₂L(CH₃COO)₂ [M = Ni(II) and Zn(II)]. The cytotoxicity activities of the compounds against human breast carcinoma MCF-7 cell line have been studied. Ligands and their Zn(II) compounds inhibited cell proliferation of MCF-7 cancer cell lines in a dose- and time-dependent manner. The free radical scavenging activity was measured by 1,1-diphenyl-2-picryl-hydrazil. Our results show that the synthesized compounds induced oxidative damage by increasing the lipid peroxidation in yeast since MDA formation was increased, and it could be concluded that the synthesized compounds caused oxidative stress. In addition, the antioxidant activities of the synthesized compounds were very much lower than those of standard antioxidants.     

Synthesis, characterization, and antibacterial activity of the ligands including thiophene/furan ring systems and their Cu(II), Zn(II) complexes

Carboxamide complexes having general formula as [ML]Cl₂·nH₂O (where M?=?Cu(II), Zn(II); n?=?0, 1/2) were synthesized using heterocyclic carboxamide ligands: 1,4-bis[3-(2-thiophenecarboxamido)propyl]piperazine (L¹) and 1,4-bis[3-(2-furancarboxamido) propyl]piperazine (L²). Their structures were characterized with elemental analysis, molar conductivity, magnetic susceptibility, and spectral methods (¹H-NMR, ¹³C-NMR, FT-IR, LC-MS). TGA and DTA curves were also performed. The structure–activity relationship for the ligands was investigated using PM3 semi-empirical method. The antibacterial activities of the carboxamides and their complexes were investigated against bacteria; Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 11230, Bacillus magaterium RSKK 5117, B. cereus RSKK 863, Salmonella enteritidis ATCC 13076, B. subtilis RSKK 244 using microdilution method.     

Synthesis and in vitro tuberculostatic activity of Co (II), Cu (II) and Ni (II) complexes of dialdehyde starch dithiosemicarbazone

Co (II), Cu (II) and Ni (II) complexes of starch dialdehyde dithiosemicarbazone (DASTSC) of low (approximately 15%) degree of oxidation were prepared and their tuberculostatic activity was tested in vitro against isoniazid-sensitive and isoniazid-resistant strains of Mycobacterium tuberculosis. In 10-week lasting tests the DASTSC complex with Ni (II) was tuberculostatic to a similar extent as was the free ligand, whereas the Co (II) and Cu (II) complexes inhibited the growth of M. tuberculosis more efficiently. It was also proved that the corresponding non-co-ordinated metal salts were inactive to both strains of M. tuberculosis.     

Synthesis,characterization and antimicrobial activity of some mixed ligand Co(II) and Ni(II) complexes

Mixed ligand Co(II) and Ni(II) complexes have been synthesized by using 8-hydroxyquinoline as primary ligand and N- and/or O- donor ligands such as tartaric acid/phenylalanine as secondary ligands. The metal complexes have been characterized on the basis of elemental analysis, electrical conductance, room temperature magnetic susceptibility measurements, spectral and thermal studies. The electrical conductance studies of the complexes in methanol solution at 10(-3) M concentration indicate their non-electrolytic nature. Room temperature magnetic susceptibility measurements are indicative of an octahedral geometry for Co(II) and Ni(II) complexes. Electronic spectra of the complexes show intra-ligand, charge transfer and the crystal field transitions, which are supportive of the proposed octahedral geometries of the complexes. The thermal analysis data of the complexes indicate the presence of crystallization water. The antibacterial and antifungal activities of the complexes have been studied again some of the pathogenic bacteria and fungi. The cup-plate method has been used to study the antibacterial activity of the compounds against C. diphtheriae, E. coli, S. typhi, S. dysentariae, S. aureus and V. cholerae. The results have been compared against those of controls, which were screened simultaneously. The activity is measured by measuring the diameter of the inhibited zone in millimeters (mm). The antifungal activity of the complexes against Candida albicans and Aspergillus niger has been studied by the tube dilution method. The complexes have been screened for acute oral toxicity in rats. The LD50 values have been determined by the method of Litchfield and Wilcoxon.     

Synthesis, characterization, and antimicrobial activity of some new 2-diazo-benzimidazole derivatives and their Ni(II), Cu(II), and Ag(I) complexes

2-Aminobenzimidazole was diazotized and made to react with active methylene compounds viz: ethylcyanoacetate and malanonitrile. The ligands [IIIa and IIIb] were isolated, characterized, and then condensed with Ni(II) chloride, Cu(II) chloride, and Ag(I) nitrate. The ligands and complexes were characterized by elemental analysis, IR, ¹H NMR, ESR, UV–Visible spectral techniques, and along with thermal studies. The antimicrobial activity of the ligands [IIIa (C₁₂H₁₁N₅O₂) and IIIb (C₁₀H₆N₆)] and their metal complexes [IVa–IVf] against bacterial strains and fungal strains were investigated. The antimicrobial activity of the above metals and the ligands were discussed.     

Synthesis,characterization, and anti-rheumatic potential of phthalazine-1,4-dione and its Cu(II) and Zn(II) complexes

Two new metal complexes derived from the reaction of 2-[(2-hydroxybenzoyl) 2,3,4a,5,10,10a-hexahydro-5,10[1′,2′]-benzenobenzo[g]phthalazine-1,4-dione] (HBPD) with Cu(II) and Zn(II) have been synthesized and characterized by using elemental analysis, spectral analysis (UV–Vis, IR, ¹H NMR, ¹³C NMR), conductance, thermal analysis, and magnetic moments. The in vivo collagen-adjuvant arthritis model in rats revealed a significant antioxidant, analgesic, and anti-rheumatic effects for HBPD and its copper and zinc complexes in comparison with standard piroxicam. The results showed that, the investigated Cu and Zn complexes have higher anti-inflammatory activity than the free ligand.     

Ni(II), Cu(II), and Zn(II) diethyldithiocarbamate complexes show various activities against the proteasome in breast cancer cells

A series of three complexes with diethyldithiocarbamate ligand and three different metals (Ni, Cu, Zn) was prepared, confirmed by X-ray crystallography, and tested in human breast cancer MDA-MB-231 cells. Zinc and copper complexes, but not nickel complex, were found to be more active against cellular 26S proteasome than against purified 20S proteasome core particle. One of the possible explanations is inhibition of JAMM domain in the 19S proteasome lid.     

Cytotoxic and antimicrobial activities of Cu(II), Co(II), Pt(II) and Zn(II) Complexes with N,O-chelating heterocyclic carboxylates

A series of Cu(II), Co(II), Pt(II) and Zn(II) coordination compounds has been prepared by the reaction of the metal chlorides with pyrazine-2-carboxylic acid, pyridine-2-carboxylic acid, imidazole-4-carboxylic acid, benzimidazole-2-carboxylic acid and 1-methylimidazole-2-carboxylic acid. The complexes were characterized by IR, UV-VIS, elemental analysis, and some by (1) H-NMR, X-ray crystallography, HPLC and LC/MS spectroscopy. All complexes consist of a 2:1 ratio of ligand to metal ion. IR and X-ray crystallography show that coordination is through the nitrogen and carboxylate oxygen donor atoms of the ligand to form chelating rings. DFT calculations predict that the trans-coordinated isomers are thermodynamically more stable than their cis-forms. Only one of five complexes studied by X-ray crystallography, Cu(II) complex of 1-methylimidazole-2-carboxylic acid showed a cis-configured metal ion center. HPLC analysis indicated that Pt(II) complex of 1-methylimidazole-2-carboxylic acid is dominated (>90%) by the trans-configured complex. All other complexes showed one isomer, presumably the trans-form. The cytotoxic activity was investigated in human cancer cell lines in vitro; only the Pt(II) complexes were active. The antimicrobial activity against four bacterial strains and one fungi was estimated by the MIC method and best results were found amongst the Co(II) complexes. These results indicate that trans-coordinated bischelating N,O-heterocyclic carboxylates of Pt(II) are an interesting new class of potential antitumor agents.     

氟苯胺席夫碱及其铜(Ⅱ)、镍(Ⅱ)配合物的合成与抑菌活性研究

目的开发新型抑菌药物.方法以水杨醛和对氟苯胺为原料合成含氟Schiff碱及其Cu(Ⅱ)、Ni(Ⅱ)配合物,并进行了初步抑菌活性研究.结果合成的Schiff碱及其配合物经元素分析、红外光谱等表征其结构组成.结论抑菌活性试验表明,合成的Schiff碱及其配合物对各供试菌株有明显的抑菌活性,抑菌效果有量效关系,其中Schiff的Cu配合物活性最强,并超过了苯甲酸.     

Physicochemical Properties and Pharmacological Activity of Mn(II), Fe(II), Co(II), Cu(II), AND Zn(II) Gluconates

Pharmaceutical Chemistry Journal -     

Synthesis, characterization, and comparative in vitro cytotoxicity studies of platinum(II), palladium(II), and gold(III) methylsarcosinedithiocarbamate complexes

This work reports on the synthesis, characterization, and in vitro cytotoxic activity of some new platinum(II), palladium(II), and gold(III) derivatives of methylsarcosinedithiocarbamate and its S-methyl ester, to study their behavior as potential antitumor agents. The biological activity of these compounds, as determined by growth inhibition and apoptosis induction, has been investigated in both human leukemic promyelocites HL60 and human squamous cervical adenocarcinoma HeLa cell lines, and their activity has been compared to the well-known platinum-based anticancer agent cisplatin. On the basis of these experimental results, [Pd(MSDT)X]n (MSDT = methylsarcosinedithiocarbamate; X = Cl, Br) complexes show a strong dose-dependent growth inhibition of both HL60 and HeLa cells, with IC(50) values slightly higher than those recorded for cisplatin; moreover, [Au(MSDT)X(2)] activity appears significantly higher or, at least, comparable to that of the reference drug. Exposure of both cell lines to [Pd(MSDT)X]n and [Au(MSDT)X(2)] complexes induces apoptosis, as determined by an Apo2.7 assay.