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Effects on pH based adsorption of nucleic acid bases (thymine and uracil) at two different concentrations 1 x 10-4 M and 1 x 10-5 M on copper, cobalt and silver ferrocyanides were studied over a pH range (1.0 – 10.0) at temperature 30±1ºC. The progress of adsorption was followed spectrophotometrically by measuring the UV absorbance of the nucleic acid base solutions at their corresponding max. Maximum adsorptions were found at neutral pH for both thymine and uracil. Effects of concentrations on adsorption of thymine and uracil on copper, cobalt and silver ferrocyanides were studied in a concentration range 10-4 – 10-5 M at neutral pH 7.0 ± 0.1 and at temperature 30±1°C. The interaction followed the Langmuir type of adsorption in general in the concentration range of 10-4 to 10-5 M of thymine and uracil solution. The uptake of nucleic bases on metal ferrocyanides followed the order of CuFc > AgFc > CoFc for the adsorption of thymine and CuFc > CoFc > AgFc for the adsorption of uracil. Effects of the presence of salts on the adsorption of thymine and uracil on metal ferrocyanides also had been studied. The insoluble metal ferrocyanides’ interaction with biomolecules must have either formed metal complexes or could have enhanced the formation of biopolymers in fluctuating environment.

Present electrophoretic method is based upon the migration of a spot of metal ions on a paper strip at different pHs of background electrolyte. A graph of pH against mobility gives information about the binary complexes and permit to calculate their stability constants. The first and second stability constants of [Hg (II) – isoleucine], [Ni (II) – isoleucine] and [Pb (II) – isoleucine] complexes were found to be (8.80 ± 0.02, 7.52 ± 0.05), (7.27 ± 0.01, 5.86 ± 0.03 and (7.17 ± 0.05, 3.32 ± 0.09) for Hg (II), Ni (II) and Pb (II) complexes, respectively at 0.01 M ionic strength and a temperature of 35°C. The study objectives of present work are (i) Look for the formation of binary complexes between the divalent metal ions and isoleucine (ii) Determine the stability constants of complexes formed (iii) To explore the possibility on applications of said binary complexes in Biology and medicine

Quantitative indication of a complex formation comes from the estimation of the stability or formation constants characterizing the equilibria corresponding to the successive addition of ligands. Paper ionophoresis is used for the study of equilibria in binary complex systems in solution. This method is based on the movement of a spot of metal ion in an electric field at various pH of background electrolyte. A graph of pH versus mobility was used to obtain information on the binary complexes and to calculate its stability constants. At an ionic strength of 0.1 M and 35ºC, the stability constants of ML and ML2 complex species of certain metal ions copper(II), manganese(II), and uranyl(II) with - α-Aminobutenoic acid and hydroxyproline were determined. The stability constants of ML and ML2 complex species of metal(II)-α-aminobutenoic acid and metal(II)– hydroxyproline were found to be [(7.70 ± 0.03, 6.38 ± 0.11), (3.19 ± 0.02, 2.07 ± 0.09), (7.32 ± 0.05, 5.49 ± 0.12)] and [(8.23 ± 0.05, 7.05 ± 0.03), (3.74 ± 0.06, 3.15 ± 0.09), (7.39 ± 0.11, 6.67 ± 0.02)] for copper(II), manganese(II) and uranyl(II) complexes, respectively. The present paper electrophoretic technique has proved to be useful in deciding whether a complex system is formed or not, and if it is formed its stability constants can also be determined.

Environmental contamination is one of the important issues that the world is facing today, it is always expanding and leading to the grave and harmful effect on the Earth. Nanoparticles have a diameter less than 100 nm exhibit new size-dependent properties compared with the bulk material. Engineered nanoparticles (ENPs) have unique characteristics in addition to the high surface area-to-volume ratio, which may increase their toxicity relative to bulk materials. Due to the high volume production of ENPs products such as carbon nanotubes, titanium dioxide, silver, zinc oxide environmental exposure to these compounds is very common. ENPs have their unique properties and applications in the areas of medicine, food& drink, construction, automotive, textiles, energy, electronics, environment etc. The present critical review is focused on the recent development of the applications of ENPs in the environmental remediation and their toxic effects.

The origin of life processes began with formation of important biomonomers from simpler molecules present in the prebiotic environment and their subsequent condensation to biopolymers. Effects on pH base adsorption of nucleic acid bases (thymine and uracil) at two different concentrations 1 x 10-4 M and 1 x 10-5 M on copper, cobalt and silver ferrocyanides were studied over a pH range (10 – 10.0) at a temperature of 30±1°C. The progress of adsorption were followed spectrophotometrically by measuring the UV absorbance of nucleic acid base solutions at their corresponding ?max. Maximum adsorptions were found at neutral pH for both thymine and uracil. Effects of concentrations on adsorption of thymine and uracil on copper, cobalt and silver ferrocyanides were studied in a concentration range 1 x 10-4 M - 1 x 10-5 M at a neutral pH 7.0 ± 0.1 and at temperature of 30±1°C. The interaction followed the Langmuir type of adsorption in general in the concentration range of 10-4 to 10-5 M of thymine and uracil solution. The uptake of nucleic bases on metal ferrocyanides followed the order of CuFc > AgFc > CoFc for the adsorption of thymine and CuFc > CoFc > AgFc for the adsorption of uracil. Effects of the presence of salts on the adsorption of thymine and uracil on metal ferrocyanides also had been studied. The insoluble metal ferrocyanides’ interaction with biomolecules must have either formed metal complexes or could have enhanced the formation of biopolymers in fluctuating environment. Adsorption of glycine and s- alanine on nickel, cobalt and cadmium ferrocyanides and adsorption of dl - aspartic acid, dl – leucine, dl – lysine and dl – serine on halosite, hectorite, illite, kaolinite, nantronite and montmorillonite clay minerals is also reported.

Los ferrocianuros de cobre, lantano, mercurio, molibdeno, plata, titanio y zinc se sintetizaron y caracterizaron mediante análisis elemental y estudios espectrales. La estabilidad de los ferrocianuros metálicos sintetizados se registró en calor (varias temperaturas), varias concentraciones de ácidos (HCl, H2SO4, HNO3, CH3 COOH) varias concentraciones de bases (NaOH, KOH, NH4OH), y en agua de mar y de grifo. Todas las estabilidades se registraron a temperatura ambiente y de ebullición. La estabilidad de los ferrocianuros metálicos sintetizados también se registró en presencia de radiación visible y ultravioleta. El potencial oxidante y fotosensibilizante de los ferrocianuros metálicos sintetizados se probó con yoduro de potasio y la solución de almidón recién preparada indicó que el ferrocianuro de cobre es un posible oxidante fuerte y fotosensibilizador. Se descubrió que los ferrocianuros de molibdeno, mercurio y tungsteno actúan como oxidante débil y fotosensibilizador. El lantano y el ferrocianuro de zinc no mostraron ningún potencial oxidante y fotosensibilizante.

Removal of p-aminophenol (PAP) and p-nitrophenol (PNP) from aqueous solution have been studied through adsorption on bismuth, lead and manganese ferrocyanides (125 μm British Sieve Standard mesh size) at pH range 1.0–10.0 and room temperature (27 ± 1°C). The progress of adsorption was followed spectrophotometrically by measuring the absorbance of PAP and PNP solutions at their corresponding λmax = 220 and 330 nm, respectively. At neutral pH, PNP was found to more adsorbed than PAP on all three metal ferrocyanides studied. Manganese ferrocyanide and bismuth ferrocyanide were found to have maximum and minimum adsorption, respectively for both adsorbents. The adsorption followed the Langmuir type of adsorption in the concentration range of 10−4 to 10−5 mol/L of PAP and PNP solutions.

Complexation reactions of isoleucine with beryllium(II) and cobalt(II) have been studied in solution phase using paper ionophoretic technique. The stability constants of ML and ML2 complexes of Be(II)—isoleucine and Co(II)—isoleucine systems have been found to be (7.49 ± 0.07, 5.89 ± 0.03) and (4.57 ± 0.11, 2.99 ± 0.09) (logarithm stability constant values), respectively at ionic strength of 0.1 mol L−1 and a temperature of 35°C.

Complexation reactions of methionine and penicillamine with copper(II) and cobalt(II) have been studied in the solution phase using a paper ionophoretic technique. This method is based on the movement of a spot of metal ion in an electric field with the complexants added in the background electrolyte at pH 8.5. The concentration of primary ligand methionine was kept constant, while that of the secondary ligand penicillamine was varied. A plot of log[penicillamine] versus mobility was used to obtain information on the mixed complexes and to calculate stability constants. The stability constants of the complexes copper(II)−methionine−penicillamine and cobalt(II)−methionine−penicillamine have been found to be 3.65 ± 0.03 and 3.05 ± 0.07 (logarithm stability constant values), respectively, at a temperature of 35 °C and ionic strength of 0.1 M.

A new method, paper electrophoresis, involving the use of a ionophoretic technique is described for the study of equilibria in binary complex system in solution. The stability constants of ML and ML2 complex species of metal(II)-α-aminobutyric acid and metal(II) — homoserine were found to be [(8.09 ± 0.03, 6.89 ± 0.09) (3.58 ± 0.07, 2.67 ± 0.11) (7.66 ± 0.06, 6.13 ± 0.02)]; [(7.80 ± 0.07, 6.45 ± 0.02) (2.93 ± 0.04, 1.97 ± 0.01) (7.41 ± 0.011, 4.67 ± 0.06)] for copper(II), manganese(II) and uranyl(II) complexes, respectively at an ionic strength 0.1 M and 35°C.

A method involving the use of paper ionophoresis is described for the study of the equilibria in mixed ligand complex systems in solution. Present method is based on the movement of a spot of metal ion under the electric field with the complexants added in the background electrolyte at pH 8.5. The concentration of primary ligand nitrilotriacetate (NTA) was kept constant while that of the secondary ligand methylcysteine was varied. The plot of log [methylcysteine] versus mobility were used to obtain information on the formation of mixed complexes and to calculate its stability constants. The binary equilibria metal(II)-methylcysteine and metal(II)-NTA have also been studied, since this is a prerequisite for the investigation of mixed complexes. The stability constants of the complexes Pb(II)-NTA-methylcysteine and UO2 (II)-NTA-methylcysteine were found to be 3.03 ± 0.05 and 3.42 ± 0.09 (log K values) at ionic strength 0.01 M and a temperature of 35°C.

A mixed complexation reaction of methionine and cysteine with copper(II) and cobalt(II) has been studied in solution phase using the paper electrophoretic technique at ionic strength 0.1 M and a temperature of 35°C. The binary equilibria copper(II)-methionine and cobalt(II)-methionine have also been studied, since this is prerequisite for the investigation of mixed complexes. The stability constants of copper(II)-methionine-cysteine and cobalt(II)-methionine-cysteine mixed complexes were found to be 2.80 ± 0.07 and 2.44 ± 0.11 (logarithm of stability constant values), respectively.

Adsorption of glycine and β-alanine on nickel, cobalt and cadmium ferrocyanides has been studied at neutral pH (7.0 ± 0.01) and room temperature (30 ± 1°C). The progress of adsorption was followed spectrophotometrically by measuring the absorbance of amino acids solution at their corresponding λmax. At neutral pH, β-alanine was found to more adsorbed than glycine on nickel, cobalt and cadmium ferrocyandies. The Langmuir type of adsorption is followed in the concentration range 10−3 to 10−4 M of glycine and β-alanine solution. Results of the present study suggest the possible importance of double metal ferrocyandides in concentrating biomolecules during the course of chemical evolution on the prebiotic earth. This process could conceivably aid in the formation of polymers in fluctuating environments.

Adsorptive interaction of p-aminophenol and p-nitrophenol in the concentration range 10(-4)-10(-5) M and at room temperature (30+/-1 degrees C) was studied with antimony, cadmium, and zirconium ferrocyanides. The interaction followed the Langmuir type of adsorption in general. The p-nitrophenol was found to have greater affinity for the antimony, cadmium, and zirconium ferrocyanides then the p-aminophenol.

have been studied insolution phase using paper electrophoresis technique. The stability constants of the complexes Cu(II)-nitrilotriacetate-penicillamine and Co(II)-nitrilotriacetate- penicillamine have been found to be 6.64 ± 0.03 and5.86 ± 0.05 (logarithm stability constant values), respectively at 35 oC and ionic strength 0.1 M.Key Words : Electrophoretic technique, Stability constants, Copper(II) complexes, Cobalt(II) complexesIntroductionThe complexation data involving body toxic or essentialmetal ions, bioactive ligand, nitrilotriacetate and penicill-amine give insight into many physico-chemical processes.The most important reactions are the processes involvingparticipation of the mercapto group and main biochemicalaspects of these have been reviewed by Jocelyn.

Stability constants of binary Fe(III)–methylcysteine, Cr(III)–methylcysteine and mixed Fe(III)–methylcysteine–cysteine, Cr(III)–methylcysteine–cysteine complexes have been determined by paper electrophoresis at 0.1 M ionic strength and a temperature of 35 °C. The stability constants of Fe(III)–methylcysteine–cysteine and Cr(III)–methylcysteine–cysteine mixed complexes were found to be 6.00±0.07 and 5.05±0.15 (logarithm of stability constant values), respectively.

The adsorption of 2,4-dinitrophenol and 2,4,6-trinitrophenol on copper, zinc, molybdenum and chromium ferrocyanides was studied at different pH and temperature. It was observed that the amount of uptake increases with temperature and the percent adsorption on metal ferrocyanides was a maximum for 2,4,6-trinitrophenol. The Langmuir-type of adsorption is followed in the concentration range 10−3 to 10−4 M for 2,4-dinitrophenol and 2,4,6-trinitrophenol solutions. Thermodynamic parameters of the process have also been evaluated.

A method involving use of paper electrophoresis is described for the study of equilibria in mixed ligand [methyl cysteine-penicillamine] complex systems in solution. The concentration of the primary ligand methyl cysteine was kept constant, while that of secondary ligand penicillamine was varied. The plots of -log [penicillamine] against mobility were used to obtain information on the formation of mixed complex and to calculate its stability constants. The binary equilibria M(III)-methyl cysteine have also been studied since this is a pre-requisite for the investigation of mixed complexes. The stability constants of [Fe(III)- methyl cysteine-penicillamine] and [Cr(III)-methyl cysteine-penicillamine] complexes were found to be 7.40 +/- 0.13 and 4.80 +/- 0.07 (log K values) for Fe(III) and Cr(III) complexes, respectively, at mu = 0.1 mol/L and at a temperature of 35 degrees C.

A method, involving the use of paper electrophoresis is described for the study of the equilibria in mixed ligand complex systems in solution. Plots of -log [methionine] against mobility were used to obtain information on the formation of mixed complexes and to calculate the stability constants. Metal (M)-methionine and M-nitrilotriacetate (NTA) binary equilibria were also studied since this is a prerequisite for the investigation of mixed complexes. The stability constants (log K) of the M-NTA-methionine complexes were found to be 6.02±0.03 and 4.92±0.01 for M=Al(III) and Th(IV), respectively, at μ = 0.1 mol/l and 35°C.

Brij Bhushan TewariDepartment of Chemistry, Faculty of Natural Sciences, University of Guyana,P.O. Box 101110, Georgetown, Guyana (S. America)Received October 5, 2001Stability constants of complexes of aluminium(III) and thorium(IV) with methionine and cysteine have beendetermined by modified paper electrophoretic technique at µ= 0.1 M. The proportion of ionic species ofmethionine and cysteine were varied by changing pH of background electrolyte. The stability constants of thecomplexes metal-methionine-cysteine have been found to be 4.31 ± 0.12 and 5.40 ± 0.19 (log K values) forAl³

Solution equilibria of binary [Fe(III)/Cr(III)–methionine] and mixed [Fe(III)/Cr(III)–methionine–penicillamine] complex systems are investigated by paper electrophoresis. Formation of 1:1:1 mixed ligand complexes is inferred and stability of these complexes were determined at 35°C and ionic strength=0.1 M/l. The stability constants of the complexes, [Fe(III)–methionine–penicillamine] and [Cr(III)–methionine–penicillamine] were found to be 6.80±0.09 and 4.60±0.16 (log K values), respectively.

A method involving the use of paper ionophoresis is described for the study of equilibria in mixed – ligand complex systems in solution. The technique is based on the movement of a spot of metal ion under an electric field with the complexants added to the background electrolyte at pH 8.5. The stability constants of the complexes Pb(II) – nitrilotriacetate – cysteine and UO 2 (II) – nitrilotriacetate – cysteine are found to be 5.35 ± 0.02 and 6.27 ± 0.07 (logarithm of stability constant values) at ionic strength 0.1 M and a temperature of 35 0C. KEY WORDS: Paper ionophoresis, Lead(II) complexes, Uranyl(II) complexes, Nitrilotriacetic acid, Cysteine, Stability constants. Bull. Chem. Soc. Ethiop. 2005, 19(2), 257-265.

The stability constants of Fe(III) and Cr(III) with methyl cysteine and nitrilotriacetate (NTA) were determined by paper electrophoretic technique. Beside binary ternary complexes have also been studied, in which nitrilotriacetate and methyl cysteine acts as primary and secondary ligand, respectively. The stability constants of mixed ligand complexes metal (M)-nitrilotriacetate-methyl cysteine have been found to be 5.72 ± 0.09 and 5.54 ± 0.11 (log K values) for Fe(III) and Cr(III) complexes, respectively, at 35 o C and ionic strength 0.1 M. KEY WORDS: Paper electrophoresis, Iron(III) complexes, Chromium(III) complexes, Mixed ligand metal complexes, Stability constants, Nitrilotriacetic acid, Methyl cysteine Bull. Chem. Soc. Ethiop. 2004 , 18(1), 29-36.

Stability constants of binary Fe(III)-methylcysteine, Cr(III)-methylcysteine and mixed Fe(III)-methylcysteine-cysteine, Cr(III)-methylcysteine-cysteine complexes have been determined by paper electrophoresis at 0.1 M ionic strength and a temperature of 35 degrees C. The stability constants of Fe(III)-methylcysteine-cysteine and Cr(III)-methylcysteine-cysteine mixed complexes were found to be 6.00 +/- 0.07 and 5.05 +/- 0.15 (logarithm of stability constant values), respectively.

Paper ionophoresis is described for the study of equilibria in a mixed ligand complex system in solution. This method is based on the movement of a spot of metal ion in an electric field with the complexants added in the background electrolyte at pH 8.5. The concentration of the primary ligand (nitrilotriacetate) was kept constant, while that of the secondary ligand (penicillamine) was varied. The stability constants of the metal-nitrilotriacetate-penicillamine complexes have been found to be 6.26 +/- 0.09 and 6.68 +/- 0.13 (log K values) for Al3+ and Th4+ complexes, respectively, at 35 degrees C and ionic strength 0.1 M.

Adsorption of Methylene Blue from aqueous solution on different sieved fractions of nickel andcobalt ferrocyanides have been studied. Nickel, cobalt ferrocyanides were synthesized, characterized.The Langmuir type of adsorption was followed in the concentration range 10-4 to 10-5 M of Methylene Bluesolution. The specific surface areas S of 100-150, 150-200, and 200-250 BSS mesh size sieved fractions were found to be 9.31, 13.69; 12.25, 17.47; and 15.07, 22.62 m2 g-1 for nickel and cobalt ferrocyanides, respectively.

Removal of o-aminophenol and o-nitrophenol from aqueous solution through adsorption on copper zinc, molybdenum, and chromium ferrocyanides were studied in pH range 2-10 at 27deg;C. At pH 7.0 o-nitrophenol adsorbed more than o-aminophenol on all the metal ferrocyanides studied. The Langmuir type of adsorption is followed in the concentration range of 10(-3) to 10(-4) M of o-aminophenol and o-nitrophenol solutions. Copyright 1997 Academic Press. Copyright 1997Academic Press

In coordination compounds studies, a knowledge of the magnitude of the stability constants of complexes is necessary for preliminary quantitative treatment. Described herein is a method that involves the use of advanced ionophoretic technique for the study of the equilibria in binary complex systems in solution. This method is based upon the migration of a spot of the metal ion on a paper strip at different pH values of background electrolyte containing 0.1 M perchloric acid and 0.01 M norvaline. A graph of pH against mobility provides information about the nature of the complexation and helps in calculating stability constants. Using this method, the stability constants of binary complexes metal(II) – norvaline have been determined to be (8.11 ± 0.02, 7.03 ± 0.09); (3.77 ± 0.11, 2.39 ± 0.07) and (7.59 ± 0.05, 6.17 ± 0.04) (log K values) for Cu(II), Mn(II) and UO2(II) complexes, respectively, at 35 ºC.