scholarly journals Investigation on Spectroscopic, Thermal and Antimicrobial Activity of Newly Synthesized Binuclear Cr(III) Metal Ion Complex

2016 ◽  
Vol 8 (2) ◽  
pp. 181-189 ◽  
Author(s):  
M. R. Islam ◽  
J. A. Shampa ◽  
M. Kudrat-E-Zahan ◽  
M. M. Haque ◽  
Y Reza

Binuclear Cr(III) metal ion complex was synthesized using diphenylacetic acid as primary ligand and 2-methyl pyridine (2-picoline) as secondary ligand. The synthesized complex was characterized by conductivity, FTIR, UV-Vis spectroscopy, magnetic moment and thermogravimetric analysis (TGA). FTIR spectra indicated the coordination of deprotonated diphenylacetic acid and 2-picoline through nitrogen and oxygen. The presence of water molecules inside the coordination sphere of the complex was confirmed from IR spectrum and TGA analysis. Binuclear and octahedral structure of the Cr(III) complex confirmed by TGA, UV-Vis spectroscopy and magnetic moment measurement. The complex showed moderate antibacterial activity with no antifungal activity.

2019 ◽  
Vol 35 (4) ◽  
pp. 1463-1468
Author(s):  
Birendra Kumar ◽  
Rekha Rani ◽  
Dayanand Prasad ◽  
Praveen Kumar Singh ◽  
Amit Kumar ◽  
...  

1-phenylazo-2-nephthol has been synthesized and used for complexation with Cu(II) metal ion along with pyridine, α-picoline, β- picoline, γ-picoline and water as secondary ligands. On the basis of elemental analysis and molar conductivity complexes were formulated as CuL2X [Where L is the prime ligand i.e 1-phenyl-azo-2-nephthol and X is the secondary ligand i.e. pyridine, α-picoline, β-picoline, and H2O.] The magnetic moment of these complexes (1.80 - 1.83 BM) indicates that these complexes are magnetically dilute. The appearance of 3 bands in the electronic spectra of complexes rules out the trigonal bipyramidal (D3h) symmetry arround Cu(II) ion in these complexes rather the electronic spectra favours square pyramidal (C4V) symmetry of these five coordinate complexes. The highest value of 10Dq clearly indicates the greater coordinating ability of α-picoline than pyridine, β-picoline and γ-picoline.


2006 ◽  
Vol 60 (3) ◽  
Author(s):  
W. Ferenc ◽  
B. Cristóvão ◽  
B. Mazurek ◽  
J. Sarzyński

AbstractSome physicochemical properties of 2-chloro-4-nitrobenzoates of Co(II), Ni(II), and Cu(II) were studied. The complexes were obtained as mono-and dihydrates with a metal ion—ligand mole ratio of 1: 2. All complexes are polycrystalline compounds. Their colours depend on the kind of central ion: pink for Co(II) complex, green for Ni(II), and blue for Cu(II) complexes. Their thermal decomposition was studied only in the range of 293 K–523 K because it was found that on heating in air above 523 K 2-chloro-4-nitrobenzoates decompose explosively. Hydrated complexes lose crystallization water molecules in one step. During dehydration process no transformation of the nitro group to nitrito one took place. Their solubilities in water at 293 K are of the orders of 10−3-10−2 mol dm−3. The magnetic moment values of 2-chloro-4-nitrobenzoates determined in the range of 76 K–303 K change from 3.48µB to 3.82µB for Co(II) complex, from 2.24µB to 2.83µB for Ni(II) 2-chloro-4-nitrobenzoate, and from 0.31µB to 1.41µB for Cu(II) complex. 2-Chloro-4-nitrobenzoates of Co(II) and Ni(II) follow the Curie—Weiss law, but the complex of Cu(II) forms dimer.


2021 ◽  
Vol 437 ◽  
pp. 213741
Author(s):  
Rui-Han Gao ◽  
Ying Huang ◽  
Kai Chen ◽  
Zhu Tao

1970 ◽  
Vol 117 (1) ◽  
pp. 129-137 ◽  
Author(s):  
Sybil M. Snaith ◽  
G. A. Levvy ◽  
A. J. Hay

1. α-Mannosidase from the limpet, Patella vulgata, was purified nearly 150-fold, with 40% recovery. β-N-Acetylglucosaminidase was removed from the preparation by treatment with ethanol. The final product was virtually free from β-galactosidase. 2. Limpet α-mannosidase was assayed at pH3.5 and at this pH it was necessary to add Zn2+ for full activity. At pH5, the enzyme had the same activity in the presence or absence of added Zn2+. 3. On incubation at acid pH, the enzyme underwent reversible inactivation, which was prevented by adding Zn2+. 4. EDTA accelerated inactivation and the addition of Zn2+ at once restored activity. No other cation was found to reactivate the enzyme. 5. Cl- had an unspecific effect on hydrolysis by limpet α-mannosidase. It increased the rate of reaction with substrate. The anion did not prevent or reverse inactivation by EDTA. 6. It is concluded that α-mannosidase is a metalloenzyme or enzyme–metal ion complex, dissociable at the pH of activity, and that it requires Zn2+ specifically.


2019 ◽  
Vol 85 (3) ◽  
pp. 3-19
Author(s):  
Polina Borovyk ◽  
Mariia Litvinchuk ◽  
Anton Bentya ◽  
Svitlana Orysyk ◽  
Yurii Zborovskiy ◽  
...  

The possibility of using N-allylcarbothioamide derivatives as well as products of their iodine- and proton-initiated electrophilic heterocyclizations as chelating agents in complexation reactions with Zn(II) and Ag(I) ions is shown. Processing of the obtained experimental data showed that N-allythioamides of pyrimidinyl (cyclohexenyl) carboxylic acids H2L1 – H2L3 and their proton- and iodo-cyclization products HL4, HL5 containing four nucleophilic reaction centers (two oxygen atoms of the carbonyl and hydroxyl groups and N-, S-carbothioamide groups or N-atoms of the dihydrothiazole moiety) are polydentate ligands capable of coordinating with metal ions to form stable six-membered chelate metallocycles. A series of new chelating mono-, bi- and polynuclear complexes Zn(II) and Ag (I) of the composition [Zn2L1,32]n, [Zn2(HL1-3)2(CH3COO)2], [Ag2(HL1,3)2]n, [Zn(HL1-3)2], [Ag(H2L3)2NO3], [Zn(HL4,5)2], K[Ag(HL4,5)2] were synthesized and isolated in solid state. Their molecular structure was established by methods of elemental chemical analysis, NMR 1H, IR and UV-Vis spectroscopy. At a ratio of M:L 1:2, complexes were isolated in which two ligand molecules H2L1 − H2L3 are coordinated to the metal ion by the sulfur atoms of the carbothioamide group and the oxygen of the mono-deprotonated hydroxyl group. It was established that the products of the proton-/iodocyclization HL4, HL5 in the complex formation pass into the thione tautomeric form with coordination through the oxygen atoms of the deprotonated hydroxyl group and nitrogen atoms of the dihydrothiazole heterocycle. At M:L 1:1, binuclear or polynuclear coordination compounds are formed. It was shown that polymerisation in complexes [Zn2L1,32]n and [Ag2(HL1,3)2]n is due to the formation of Zn−(O2SN)−Zn and Ag−O−Ag polymer chains. Investigation of the solubility of the resulting complexes showed that the polymer complexes are weakly soluble or insoluble in DMSO, DMF, while the mononuclear are soluble in methanol, as well as in water.


Author(s):  
Anjapuli Ponnuvel ◽  
Arumugam Pillai Kala ◽  
Karachalacherevu Seetharamiah Nagaraja ◽  
Chandran Karnan

The polymeric title complex, poly[hexa-μ-aqua-diaquatetra-μ-cyanurato-tetralithium] [Li4(C3H2N3O3)4(H2O)7] n , synthesized at room temperature from an aqueous solution of lithium hydroxide and cyanuric chloride, crystallizes in the triclinic space group P\overline{1}. There are two distinct Li+ cations in the asymmetric unit, one of which, Li1, has distorted trigonal–bipyramidal geometry and is coordinated via oxygen to two cyanurate anions occupying equatorial positions, and three water molecules, two in the axial positions and the third in an equatorial position. One of the axial water ligands and the equatorial water ligand are involved in bridging to a crystallographically equivalent Li1 cation. A centre of inversion lies between the two Li1 cations and the Li1...Li1 distance is 3.037 (5) Å. The remaining axial water ligand bridges to the second Li cation, Li2, which is disordered over two crystallographic sites with approximately equal occupancy, and has an Li1...Li2 distance of 3.438 (7) Å. The terminal Li2 cation is coordinated to three water molecules and an oxygen atom from a cyanuric anion and has a distorted tetrahedral geometry. A three-dimensional network of intermolecular hydrogen bonds involving N—H...O, O—H...O and O—H...N interactions serves to hold the structure together, as confirmed by a Hirshfeld surface analysis. The title compound was further characterized using IR and UV–vis spectroscopy and TG–DTA analysis.


2013 ◽  
Vol 10 (3) ◽  
pp. 597-606
Author(s):  
Baghdad Science Journal

New (pentulose-?-lactone-2,3-enedibenzoate barbituric acid) (L) have been synthesized by reaction of (5-C-dimethyl malonyl-pentulose-?-lactone-2,3-enedibenzoate) with urea in alkaline media (sodium methoxide). (Ca+2, Co+2, Ni+2, Cu+2, Zn+2, Cd+2 and Hg+2) complexes of (pentulose-?-lactone-2,3-enedibenzoate barbituric acid) (L) have been prepared and characterized by (1H and 13CNMR), FTIR, (U.V-Vis) spectroscopy, Atomic absorption spectrophotometer (A.A.S), Molar conductivity measurements and Magnetic moment measurements, and the following general formula has been given for the prepared complexes [MLCl2(H2O)].XH2O, where M = (Ca+2, Co+2, Ni+2, Cu+2, Zn+2, Cd+2, Hg+2), X = five molecules with (Cd+2) complex, L = (pentulose-?-lactone-2,3-enedibenzoate barbituric acid).


2016 ◽  
Vol 72 (10) ◽  
pp. 1412-1416
Author(s):  
Monserrat Alfonso ◽  
Helen Stoeckli-Evans

The title isotypic complexes, bis[μ-5,6-bis(pyridin-2-yl)pyrazine-2,3-dicarboxylato]-κ4N1,O2,N6:O3;κ4O3:N1,O2,N6-bis[diaquamanganese(II)] tetrahydrate, [Mn2(C16H8N4O4)2(H2O)4]·4H2O, (I), and bis[μ-5,6-bis(pyridin-2-yl)pyrazine-2,3-dicarboxylato]-κ4N1,O2,N6:O3;κ4O3:N1,O2,N6-bis[diaquairon(II)] tetrahydrate, [Fe2(C16H8N4O4)2(H2O)4]·4H2O, (II), are, respectively, the manganese(II) and iron(II) complexes of the ligand 5,6-bis(pyridin-2-yl)-pyrazine-2,3-dicarboxylic acid. The complete molecule of each complex is generated by inversion symmetry. Each metal ion is coordinated by a pyrazine N atom, a pyridine N atom, two carboxylate O atoms, one of which is bridging, and two water O atoms. The metal atoms haveMN2O4coordination geometries and the complexes have a cage-like structure. In the crystals of both compounds, the complexes are linked by O—H...O and O—H...N hydrogen bonds involving the coordinating water molecules, forming chains along [100]. These chains are linked by O—H...O hydrogen bonds involving the non-coordinating water molecules, forming layers parallel to (011). The layers are linked by pairs of C—H...O hydrogen bonds and offset π–π interactions, so forming a hydrogen-bonded three-dimensional framework.


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