nan Mudasir

DNA binding of iron(II) mixed-ligand complexes containing 1,10-phenanthroline and 4,7-diphenyl-1,10-phenanthroline

Absorption spectroscopy and circular dichroism (CD) have been used to characterize the DNA binding of [Fe(phen)3]2+, [Fe(phen)2(DIP)]2+ and [Fe(phen)(DIP)2]2+ where phen and DIP stand for 1,10-phenanthroline and 4,7-diphenyl-1,10-phenanthroline, respectively. Both [Fe(phen)3]2+ and [Fe(phen)2(DIP)]2+ bind weakly to calf thymus DNA (CT-DNA) in an electrostatic mode, while [Fe(phen)(DIP)2]2+ binds more strongly to CT-DNA, possibly in an intercalation mode. The hypochromicity, red shift and Kb increase in the order [Fe(phen)3]2+ < [Fe(phen)2(DIP)]2+ < [Fe(phen)(DIP)2]2+ in accordance with the increase in size and hydrophobicity of the iron(II) complexes. The thermodynamic parameters obtained suggest that the DNA binding of both [Fe(phen)3]2+ and [Fe(phen)2(DIP)]2+ is entropically driven, while that of [Fe(phen)(DIP)2]2+ is enthalpically driven. A strong CD spectrum in the UV and visible region develops upon addition of CT-DNA into the racemate solution of each iron(II) complex (Pfeiffer effect). This has revealed that a shift in diastereomeric inversion equilibrium takes place in the solution to yield an excess of one of the DNA-complex diastereomers. The striking resemblance of the CD spectral profiles to those of the pure delta-enantiomer indicates that the delta-enantiomer of the iron(II) complexes is preferentially bound to CT-DNA. The mechanism of the development of Pfeiffer CD is proposed on the basis of kinetic studies on the DNA binding of the racemic iron(II) complexes.

DNA binding of iron(II) complexes with 1,10-phenanthroline and 4,7-diphenyl-1,10-phenanthroline: salt effect, ligand substituent effect, base pair specificity and binding strength

The DNA binding of iron(II) mixed-ligand complexes containing 1,10-phenanthroline(phen) and 4,7-diphenyl-1,10-phenanthroline(dip), [Fe(phen)(3)](2+), [Fe(phen)(2)(dip)](2+) and [Fe(phen)(dip)(2)](2+) has been characterized by spectrophotometric titration and melting temperature measurements. The salt concentration dependence of the binding constant has allowed us to dissect the DNA-binding constant and free energy change of each iron(II) complex into the nonelectrostatic and polyelectrolyte contributions. A comparison of the nonelectrostatic components in the binding free energy changes among iron(II) complexes has made it possible to rigorously evaluate the contribution of the ligand substituents to the DNA-binding event. The peripheral substitution of phen by two phenyl groups increases the nonelectrostatic binding constant of the iron(II) complex more than 20 times, which is equivalent to approximately 7.5 kJ mol(-1) of more favorable contribution to the DNA binding. In general, the iron(II) complexes studied have higher affinity towards the more facile A-T sequence than the G-C sequence. This preferential binding may be attributed to the steric effect induced by the ancillary part of the ligands in the course of DNA binding. The binding of disubstituted iron(II) complex to DNA is quite strong as reflected in the modest increase in the denaturation temperature (T(m)) of double helical DNA upon the interaction with the iron(II) complex.

Ion paired chromatography of iron (II,III), nickel (II) and copper (II) as their 4,7-Diphenyl-1,10-phenanthroline chelates

A reversed phase ion-paired chromatographic method that can be used to determine trace amounts of iron (II,III), nickel (II) and copper (II) was developed and applied to the determination of iron (II) and iron (III) levels in natural water. The separation of these metal ions as their 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline) chelates on an Inertsil ODS column was investigated by using acetonitrile-water (80/20, v/v) containing 0.06 M perchloric acid as mobile phase and diode array spectrophotometric detection at 250-650 nm. Chromatographic parameters such as composition of mobile phase and concentration of perchloric acid in mobile phase were optimized. The calibration graphs of iron (II), nickel (II) and copper (II) ions were linear (r > 0.991) in the concentration range 0-0.5, 0-2.0 and 0-4.0 mug ml(-1), respectively. The detection limit of iron (II), nickel (II) and copper (II) were 2.67, 5.42 and 18.2 ng ml(-1) with relative standard deviation (n = 5) of 3.11, 5.81 and 7.16% at a concentration level of 10 ng ml(-1) for iron (II) and nickel (II) and 25 ng ml(-1) for copper (II), respectively. The proposed method was applied to the determination of iron(II) and iron(III) in tap water and sea water samples without any interference from other common metal ions.

DNA-Binding Properties of Iron(II) Mixed-Ligand Complexes Containing 1,10-Phenanthroline and Dipyrido(3,2-a:2',3'-c)phenazine

An iron(II) mixed-ligand complex with 1,10-phenanthroline (phen) and dipyrido[3,2-a:2’,3’- c]phenazine (dppz), [Fe(phen)2(dppz)]2+, has been synthesized. The DNA-binding properties of the mixed-ligand complex have been studied in terms of equilibrium binding constant, thermodynamic parameter, thermal denaturation as well as Pfeiffer effect upon binding to DNA. The spectrophotometric titration of [Fe(phen)2(dppz)]2+ with calf thymus DNA (ct-DNA) has shown that the iron(II) mixed-ligand complex binds effectively to ct-DNA in an intercalation mode as indicated by remarkable hypochromicity (ca. 36%) and moderate bathochromic shift (8 nm) of the absorption spectra. This intercalative mode is supported by a significant increase (Δ Tm = 21 °C) in the melting temperature (Tm) of ct-DNA at R([complex]/[ct-DNA]) = 1.5. The binding of [Fe(phen)2(dppz)]2+ to ct-DNA is entropically driven as characterized by a positive enthalpy change and a large negative TΔ S term. An intense CD signal in the UV and visible region develops upon addition of ct-DNA to the racemate solution of [Fe(phen)2(dppz)]2+. This has revealed that a shift in diastereomeric inversion equilibrium takes place in the solution to yield an excess of one enantiomer of the DNA-iron(II) complex (Pfeiffer effect). The striking resemblance of the CD spectral profiles to those of the corresponding Δ -enantiomer indicates that Δ -[Fe(phen)2(dppz)]2+ is preferentially bound to ct-DNA

Preparation of crosslinked carboxymethyl chitosan with epichlorohydrin and its use for Pb(II) removal

A modified pectin has been synthesized by reacting/combining -OH group among pectin and chitosan with ECH (Epichlorohydrin) croslinker agent. Chitosan was grafted with acetate to form carboxymetyl chitosan (CMC). The result of this study was Pectin-CMC-ECH film could be greater adsorp Pb(II) ion than chitosan without modified. The structure of Pectin-CMC-ECH film was characterized by Fourier transform infrared (FTIR) spectroscopy. Adsorption experiment were performed in batch processes; Result of the study showed that optimum conditions for the adsorption of Pb(II) on the adsorbent were found at pH 5 with with 93 % of adsorption and adsorption capacity was 42.77 mg/g, contact time 12 hour with 91 % of adsorption and adsorption capacity was 39.74 mg/g. Pectin-CMC-ECH film demonstrate the ability to absorb Pb (II) metal ions was higher than chitosan without modified.

Preparation of TiO2 photocatalyst with the matrix of palm wood (Arenga pinnata) waste in the photodegradation of batik wastewater

The study aimed to the preparation of TiO2 photocatalyst with the matrix from palm wood waste whose has lignin and cellulose content. TiO2 photocatalyst with the matrix from the wastewater of palm wood waste (TiO2/pww) was used as photocatalyst in photodegradation of batik wastewater. TiO2 solid was dissolved in ethanol and aquadest, added with the powder of wood palm waste and stirred with a magnetic stirrer for 16 hours. Then separation was carried out using buchner and filtrate and residue were obtained. The filtrate was disposed and the residue was calcined with various temperatures for 3 hours. The temperatures in this research were 100 °C (TiO2/pww-100); 200°C (TiO2/pww-200); 300°C (TiO2/pww-300). Analysis and characterization of TiO2/wwp were conducted using X-ray diffraction (XRD) and spectrophotometer Fourier Transform Infra Red (FTIR) methods. Photocalalytic TiO2/wwp use the batch system in a reactor with UV light 40 watts, 220 volts and length wave 360 nm the plate magnetic stirrer. Liquid waste batik adds TiO2/wwp with time variation. At XRD analysis showed that the preparation of TiO2/pww could be done on the heating TiO2/pww temperature of 100°C and 200°C. At the temperature of 300°C, it was indicated that the lignocelluloses in palm wood waste were burned, meaning that few lignocelluloses remained. The result of FTIR analysis showed clearly that at the temperature of 300°C, a few spectrum of lignocelluloses remained in palm wood waste, while at a temperature of 100°C and 200°C, spectra of lignocelluloses of palm wood waste remained. The result of photocatalysis test indicated that TiO2/pww could reduce 40%, 72%, 81% and 64% COD for TiO2 (control), TiO2/pww-100, TiO2/pww-200 and TiO2/pww-300, respectively.

Effect of sulfuric acid concentration of bentonite and calcination time of pillared bentonite

An activation of natural clay has been developed. Activation was applied by refluxing the natural bentonite in variation of the sulfuric acid concentration and calcination time of pillared bentonite (PLC). Calcination was applied using oven in microwave 2,45 GHz. Determination of acidity was applied by measuring the amount of adsorbed ammonia and pyridine. Morphological, functional groups and chrystanility characterizations were analyzed using SEM, TEM, FTIR and XRD. Porosity was analyzed using SSA.The results showed that the greater of the concentration of sulfuric acid and calcination time was, the greater the acidity of bentonite as well as the pore diameter were. FTIR spectra showed no fundamental changes in the structure of the natural bentonite, SEM, and TEM images were showing an increase in space or field due to pillarization while the XRD patterns showed a shift to a lower peak. Optimization was obtained at a concentration of 2 M of sulfuric acid and calcination time of 20 minutes, keggin ion of ...

The preparation of polyelectrolyte complexes carboxymethyl chitosan(CMC)-pectin by reflux method as a Pb (II) metal ion adsorbent

Aim of this research is to synthesized a chemically stable polyelectrolyte complexs carboxymetyl chitosan CMC-pectin as Pb(II) ion adsorbent by reflux method. During synthesis process, the optimum mass ratio of CMC and pectin was pre-determined and the active groups of the CMC-pectin complex was characterized by using IR spectrofotometer. Finally, adsorption capacity of the adsorbent material for Pb (II) ions was studied under optimum condition, i.e. adsorbent mass, contact time, and pH. Result shows that CMC could be succesfully combined with pectin to produce CMC-pectin complex. The optimum mass ratio CMC: pectin to form the polyelectrolyte complexs CMC-pectin was 70% : 30%. The active groups identified in the CMC-pectin complex was a hydroxyl (OH) and carboxylate (-COOH) groups. The optimum conditions for Pb (II) ion absoprtion was 10 mg of the adsorbent mass, 75 min of contact time, and pH 5. This material can be effectively used as adsorbents for Pb (II) ions, where up to 91% Pb (II) metal ions was a...

Preparation of Pb(II)-Imprinted-Carboxymethyl Chitosan-Pectin-BADGE Film as Sorbent for Pb(II) Ion

Cross-linked metal-imprinted Carboxymethyl Chitosan-Pectin (CMC-Pec) were prepared from CMC and pectin, using Pb (II) ion as a template and Bisphenol A diglycidil ether (BADGE) as the cross-linking agent. The film was prepared in order to obtain a selective adsorbent for Pb (II) ion. The film was characterized using infrared (IR) spectroscopy. The result showed that the active group of the Pb (II)-imprinted CMC-Pec-BADGE film was hydroxyl group (-OH) and carboxylic (-COOH) as indicated by IR peaks at the wave number 3300-3600 cm-1 and 1600-1800 cm-1, respectively. The Pb (II) adsorption capacity of the Pb (II)-imprinted CMC-Pec-BADGE film was 12.18 mg/g. The film showed a selective adsorption for Pb (II) metal ions compared to the adsorption of Zn (II) and Cu (II) in mole ratio of 1: 1: 1.

LIGAND-EXCHANGE REACTION BETWEEN TRIS(1,10-PHENANTHROLINE)METAL(II) AND TRIS(4,7-DIPHENYL-1,10-PHENANTHROLINE)METAL(II) IONS

Abstract The ligand exchange reaction between [M(phen)3]2+ and [M(DIP)3]2+ (where M is the same and M = FeII or NiII, phen = 1,10-phenanthroline, DIP = 4,7-diphenyl-1,10-phenanthroline) has been investigated by reversed phase ion-paired chromatography (RP-IPC). The effect of pH and solvent on the ligand-exchange reaction is studied by monitoring the variation in chromatograms with time after mixing. The results have shown that the ligand exchange reaction between [M(phen)3]2+ and [M(DIP)3]2+ takes place in the pH range of 3–8 and the rate of reaction for nickel(II) complexes is about two times slower than that for iron(II) complexes. Experiments on the effect of various solvents on the ligand-exchange reaction have revealed that the rate of reaction is enhanced by the solvent in the following order: (CH3)2CO > CHCl3 ≥ CH2Cl2 > CH3CN > CH3OH. Elemental analysis and UV-visible spectroscopy confirmed that the products obtained from the ligand-exchange reaction are mixed-ligand complexes containing phen and DIP ligands, i.e., [M(phen)2(DIP)]2+ and [M(phen)(DIP)2]2+.