Cobalt (III) Complexes of thiosemicarbazone derived from 2-acetyl pyridine, 2-acetyl thiophene with alkyl and aryl substituted thiosemicarbazide and their antimicrobial activities (original) (raw)
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International Journal of Scientific Research in Science and Technology, 2023
An interesting series of cobalt(II) complexes of the new ligands: The antipyrinethiosemicarbazones 4[N-(benzalidene) amino]antipyrinethiosemicarbazone (BAAPTS), 4[N-(2-hydroxy-benzalidene)amino]antipyrinethiosemicarbazone (2b), and 4[N-(2-hydroxy-1-naphthalidene)amino]antipyrinethiosemicarbazone (2c) The complexes were discovered to have the typical stoichiometry [CoX2(H2O)(L)] and [Co(L)2](ClO4)2, where X = Cl, NO3, NCS, or CH3COO, and L =2a, 2b, or 2c. Elemental analyses, molar conductivity measurements, molecular weight estimations, magnetic moments at room temperature, infrared, and electronic spectra were used to describe the complexes. The behaviour of each and every thiosemicarbazone is that of neutral tridentate (N, N, S) donor ligands. The perchlorate complexes are 1:2 electrolytes, but the chloro, nitrato, thiocyanato, and acetate complexes are essentially non-electrolytes, according to the conductivity measurements in PhNO2 solution. Studies on thermodynamic behavior were conducted for a few typical complexes, and a decomposition process was suggested. The cobalt(II) complexes of the ligands and their antibacterial and antifungal activities have also been studied, and it has been found that the complexes are more effective bactericides than the ligands.
Cobalt(III) complexes containing pyridoxal N(4)-substituted thiosemicarbazone ligands with the composition [Co(HL 1À2 ÁCl)(HL 1À2 ÁH 2 O)] (1–2) have been synthesized from the reaction of [CoCl 2 (PPh 3) 2 ] and pyridoxal N-methyl-thiosemicarbazone hydrochloride (H 3 L 1 ÁCl)/pyridoxal N-phenyl-thiosemicarbazone hydrochloride (H 3 L 2 ÁCl). The richness of the coordination chemistry of this ligand is highlighted by the modulation of its charge from neutral (H 3 LÁCl) (L) to dianionic (HLÁCl) (L 2À) and monoanionic forms (HLÁH 2 O) (L À) and coordinated as tridentate binegative mode around cobalt(III) ion by forming neutral complex. The new complexes were characterized by various analytical and spectroscopic techniques (IR, electronic, 1 H NMR and ESI-Mass). The X-ray crystal structure of the complex 2, demonstrated distorted octahedral coordination geometry around the metal centre. Further, the investigation of effect of substitution (CH 3 or C 6 H 5) on terminal N(4)-nitrogen of thiosemicarbazone exhibited its influence on the potential binding and cleavage ability with DNA, BSA binding, free radical scavenging and cytotoxicity.
Inorganics
New complexes of trivalent cobalt with substituted thiosemicarbazone ligands having an NNS donor system {HL1 = 4-(4-nitrophenyl)-1-((pyridin-2-yl)methylene)thiosemicarbazide and HL2 = 4-(2,5-dimethoxyphenyl)-1-((pyridin-2-yl)methylene)thiosemicarbazide} were synthesized via the in situ oxidation of divalent cobalt chloride accompanying its addition to the ligands. The complexes C1 and C2 were characterized via elemental (CHNS) analysis and 1H NMR, FT-IR and UV-Vis. spectroscopic data. Further, conductometric studies on the DMF solutions of the complexes indicated their 1:1 nature, and their diamagnetism revealed the low-spin trivalent oxidation state of the cobalt in the complexes. The X-ray diffraction analysis of complex C1 indicated that it crystallizes in the triclinic space group P-1. The metal exhibits an octahedral environment built by two anionic ligands bound via pyridine nitrogen, imine nitrogen and thiol sulfur atoms. The complex is counterbalanced by a chloride ion. In a...
2015
Newly synthesized Copper (II) complexes of semi-and thiosemicarbaziones, derived from condensation with 2-acetyl pyrrole, 2-acetyl pyridine and 2-acetyl thiophene. The isolated solid complexes were characterized by elemental analysis, electronic spectra, infrared spectra, 1 H N.M.R spectra, mass spectra, magnetic susceptibilities and molar conductivity measurements. The redox properties of the complexes were studied cyclic voltammetrically. The complexes were found to form tetrahedral to distorted square planar in geometry. The ligands and isolated complexes were screened for antibacterial and antifungal activities and show appreciable amount of microbial activities.
Cobalt(III) Complexes with Thiosemicarbazones as Potential anti- Mycobacterium tuberculosis Agents
Journal of the Brazilian Chemical Society, 2014
Complexos de Co III derivados da 2-acetilpiridina N(4)-R tiossemicarbazona (Hatc-R, R = alquil ou aril) foram caracterizados por análise elementar, espectroscopia na região do infravermelho, UV-Visível e 1 H RMN, voltametria cíclica (VC), medidas de condutividade e difração de raios X em monocristal. Os resultados obtidos são consistentes com a oxidação do centro de Co II para Co III após a coordenação N,N,S-tridentada e monoaniônica dos ligantes tiossemicarbazonas, resultando em complexos octaédricos iônicos do tipo [Co(atc-R) 2 ]Cl. Os estudos de eletroquímica mostram dois processos reversíveis, referentes aos pares redox Co III /Co II e Co II /Co I , que são afetados pelo efeito indutivo dos grupos substituintes na posição N4 dos ligantes. Dois complexos de Co III se mostraram satisfatoriamente ativos, com valores de concentração inibitória mínima abaixo de 10 μmol L -1 e um deles apresentou muito baixa citotoxicidade contra células VERO e J774A.1 (IC 50 ), conferindo-lhe altos índices de seletividade (SI > 10).
Journal of Thermal Analysis and Calorimetry, 2014
The synthesis of a potentially bioactive mixedvalence Co III /Co II complex with 2-acetylpyridine Smethylisothiosemicarbazone (HL) ligand is described. The crystal and molecular structure of the formed [Co III L 2 ] [Co II Cl 3 py]ÁMe 2 CO (I) compound (py stands for pyridine) is determined by single-crystal X-ray crystallography. It's thermal decomposition along with the decomposition of the ligand and six structurally related complexes with formulas [CoL 2 ]NO 3 ÁMeOH (1), [CoL 2 ]BrÁMeOH (2), [CoL 2 ] HSO 4 ÁMeOH (3), [CoL 2 ] 2 [Co II (NCS) 4 ] (4), [Co(HL) (L)]I 2 Á2MeOH (5), and [Co(HL)(L)][Co II Cl 4 ]ÁMeOH (6) was determined by simultaneous TG/DSC measurements. The decomposition pattern is evaluated using TG/DTA-MS data. The results were related to the solvent/moisture content and the decomposition mechanism of the compounds. The antimicrobial activity of the ligand and of all the complexes was tested in vitro for selected gram-negative and gram-positive bacteria and fungi. The activity of the ligand against all tested bacteria is comparable with those obtained for standard antibiotics, while it is less active against fungi. Surprisingly, the activity of the complexes is very low. The low antimicrobial activity of the complexes may be in connection with their high thermodynamic and kinetic inertness in solution. The results are also supported by the relatively high thermal stability of the complexes.
Cobalt (III) complexes of formyl-and acetylpyrazine N (4)-substituted thiosemicarbazones
Transition Metal Chemistry, 1997
Cobalt(III) complexes of acetyl-and formylpyrazine N(4)-substituted thiosemicarbazones have been synthesized and characterized by spectral and physical techniques. The crystal structure of the bis{formylpyrazine N(4)-methylthiosemicarbazone}cobalt(III) complex shows the two ligands coordinated in a mer-con®guration, and the orientation of the thiosemicarbazone moiety's N(4)methyl is Z with respect to the thiolato sulfur in both ligands. Included is the crystal structure of the bis-{2-acetylpyridine N(4)-propylthiosemicarbazone}cobalt(III) complex in which the two thiosemicarbazone ligands are also in the mer-con®guration, but one ligand has the propyl group oriented Z with respect to the thiolato sulfur and the other E. Both complexes' bond lengths and bond angles are compared with other cobalt(III) thiosemicarbazone complexes.
Molecules
Herein, we report the synthesis of eight new mononuclear and binuclear Co2+, Ni2+, Cu2+, and Zn2+ methoxy thiosemicarbazone (MTSC) complexes aiming at obtaining thiosemicarbazone complex with potent biological activity. The structure of the MTSC ligand and its metal complexes was fully characterized by elemental analysis, spectroscopic techniques (NMR, FTIR, UV-Vis), molar conductivity, thermogravimetric analysis (TG), and thermal differential analysis (DrTGA). The spectral and analytical data revealed that the obtained thiosemicarbazone-metal complexes have octahedral geometry around the metal center, except for the Zn2+-thiosemicarbazone complexes, which showed a tetrahedral geometry. The antibacterial and antifungal activities of the MTSC ligand and its (Co2+, Ni2+, Cu2+, and Zn2+) metal complexes were also investigated. Interestingly, the antibacterial activity of MTSC- metal complexes against examined bacteria was higher than that of the MTSC alone, which indicates that metal c...
Complexes of 3dn Metal Ions with Thiosemicarbazones: Synthesis and Antimicrobial Activity
Molecules, 2007
The chelating behavior of the thiosemicarbazone derivatives of 2-hydroxy-8-Rtricyclo[7.3.1.0. 2,7 ]tridecane-13-one (where R = H, CH 3 , C 6 H 5 ) towards Co(II), Ni(II) and Cu(II) has been investigated by elemental analysis, molar conductivity measurements, UV-VIS, IR, ESR spectroscopy and thermal studies. It was deduced from the experiments performed that the ligands coordinate to metal ions in different ways -neutral bidentate or mononegative bidentate -depending on the nature of R. Also, if metal acetates are used instead of metal chlorides, the ligands coordinate in a mononegative bidentate fashion, regardless of the nature of R or the thiosemicarbazone type ligand. The antimicrobial activity of the ligands and of the complexes towards samples of Acinetobacter boumanii, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa was determined.