scholarly journals Synthesis of New Five Coordinated Copper(II) and Nickel(II) Complexes of L-Valine and Kinetic Study of Copper(II) with Calf Thymus DNA

2002 ◽  
Vol 9 (1-2) ◽  
pp. 81-90 ◽  
Author(s):  
Aijaz Ahmad Tak ◽  
Farukh Arjmand ◽  
Sartaj Tabassum

Five coordinated novel complexes of CuII and NiII have been synthesized from benzil and 1,3- diaminopropane-CuII/NiII complex and characterized by elemental analysis, i.r., n.m.r., e.p.r, molar conductance and u.v-vis, spectroscopy. The complexes are ionic in nature and exhibit pentaeoordinated geometry around the metal ion. The reaction kinetics of C25H36N5O2CuCl with calf thymus DNA was studied by u.v-vis, spectroscopy in aqueous medium. The complex after interaction with calf thymus DNA shows shift in the absorption spectrum and hypochromicity indicating an intercalative binding mode. The Kobs values have been calculated under pseudo-first order conditions. The redox behaviour of complex C25H36N5O2CuCl in the presence and in the absence of calf thymus DNA in the aqueous solution has been investigated by cyclic voltammetry. The cyclic voitammogram exhibits one quasi-reversible redox wave corresponding to CuII/CuI redox couple with E1/2 values of -0.377 and -0.237 V respectively at a scan rate of 0.1Vs-1 .On interaction with calf thymus DNA, the complex C25H36N5O2CuCl exhibits shifts in both Ep as well as in E1/2 values, indicating strong binding of the complex to the calf thymus DNA.

2021 ◽  
Vol 13 (2) ◽  
pp. 25
Author(s):  
Hamzeh M. Abdel-Halim ◽  
Hutaf M. Baker ◽  
Akef I. Alhmaideen ◽  
Adnan S. Abu-Surrah

Kinetics of oxidation of L-cysteine by new series of substituted ONNO-donor salen-type Schiff base complexes of general formula [MIII(L)Cl] (M = Co, Fe, Cr; L = Schiff base ligand) have been studied in aqueous solutions. Measurements were run at constant temperature (25º C), constant ionic strength (0.20 M), and constant pH (7.0) under pseudo-first order conditions, in which the concentration of cysteine is around two orders of magnitude greater than that of metal complex. The observed rate constant was determined by following the change in absorbance of reaction mixture at a predetermined wavelength with time. Results show that the rate of oxidation depends on the type of metal center, with Co(III) complexes were found to have the highest rates due to higher reduction potential of Co(III). The oxidation rate was also found to depend on steric factor and the electron withdrawing / releasing ability of the ligand bound to the metal ion.


2007 ◽  
Vol 3 (1) ◽  
pp. 133-142 ◽  
Author(s):  
Ishaq Abdullah Zaafarany

Abstract          The kinetics of sol-gel transformation between A13+, La 3+ and Th4+ metal ion electrolytes and sodium alginate sol have been studied complexometrically at various  temperatures. In the presence of a large excess of sodium alginate sol concentration over that of metal ion electrolyte, the pseudo first–order plots of exchange showed sigmoidal curves with two distinct stages. The initial part was relatively fast and curved significantly at early times, followed by a slow decrease in the rates of exchange over longer time periods. The rate constants of gelation showed second-order overall kinetics which was first order in the concentration of both reactants. The thermodynamic parameters have been evaluated and tentative gelation mechanisms consistent with the kinetic results of gelation are suggested. The stability of these ionotropic metal-alginate complexes has been discussed in terms of the coordination geometry and strength of chelated bonds.


RSC Advances ◽  
2014 ◽  
Vol 4 (108) ◽  
pp. 63549-63558 ◽  
Author(s):  
Saptarshi Ghosh ◽  
Pronab Kundu ◽  
Bijan Kumar Paul ◽  
Nitin Chattopadhyay

Binding mode of biologically relevant anionic probe, ANS, with ctDNA is divulged from spectroscopic and molecular docking studies.


2018 ◽  
Vol 22 (09n10) ◽  
pp. 739-750 ◽  
Author(s):  
An-Na Xie ◽  
Zhao Zhang ◽  
Hua-Hua Wang ◽  
Atif Ali ◽  
Dong-Xu Zhang ◽  
...  

A new tin(IV) corrole, 5,10,15-tris(4-methoxycarbonylphenyl) corrole tin(IV) (1-Sn) was synthesized and characterized. The DNA binding, photocleavage and anti-cancer activity were studied and compared with its free-base. The interaction of 1-Sn and its free-base 1 with calf thymus DNA had been investigated by spectroscopic methods, viscosity measurements and molecular docking analysis. The results revealed that 1-Sn and 1 could interact with calf thymus DNA via an outside groove binding mode. Furthermore, although 1 displayed no photonuclease activity, 1-Sn exhibited good photonuclease activity as indicated by agarose gel electrophoresis, and superoxide anion might be the active intermediate for the DNA scission. Finally, 1 was nontoxic but 1-Sn displayed cytotoxicity towards A549 tumor cell lines.


2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Partha Sarathi Guin ◽  
Piyal Das ◽  
Saurabh Das ◽  
Parikshit Chandra Mandal

Hydroxy-9,10-anthraquinones are cheaper alternatives to anthracycline drugs. They closely resemble anthracycline drugs both from a structural and functional viewpoint. Electrochemical behavior of the Ni(II) complex (Na2[Ni(NaLH)2Cl2]⋅2H2O) of sodium 1,4-dihydroxy-9,10-anthraquinone-2-sulphonate (NaLH2), analogue of the core unit of anthracycline anticancer drugs, was studied at physiological pH using cyclic voltammetry. The Ni(II) complex of sodium 1,4-dihydroxy-9,10-anthraquinone-2-sulphonate undergoes diffusion-controlled one-electron reduction that enables performing an electrochemical study on the interaction of the complex with calf thymus DNA. The complex was titrated with increasing concentrations of DNA, and the reduction peak for the unbound complex helped in evaluating binding parameters. Analysis of binding data using nonlinear curve fit in a cyclic voltammetry experiment is the first such attempt. The paper evaluates site size of interaction that also serves as a means to determine stoichiometry of complex formation, between a metal ion and ligand from a DNA interaction study, probably a first of its kind.


2001 ◽  
Vol 56 (3) ◽  
pp. 281-286 ◽  
Author(s):  
Ceyhan Kayran ◽  
Eser Okan

Abstract The kinetics of the thermal substitution of norbornadiene (nbd) by 2,2'-bipyridine (2,2'-bipy) in (CO)4Mo(C7H9) was studied by quantitative FT-IR and UV-VIS spectroscopy. The reaction rate exhibits first-order dependence on the concentration of the starting complex, and the observed rate constant depends on the concentration of both leaving nbd and entering 2,2'-bipy ligand. The mechanism was found to be consistent with the previously proposed one, where the rate determining step is the cleavage of one of the two Mo-olefin bonds. The reaction was performed at four different temperatures (35 -50 °C) and the evaluation of the kinetic data gives the activation parameters which now support states.


2010 ◽  
Vol 114 (13) ◽  
pp. 4686-4691 ◽  
Author(s):  
Fernando Secco ◽  
Marcella Venturini ◽  
Tarita Biver ◽  
Francisco Sánchez ◽  
Rafael Prado-Gotor ◽  
...  

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