Akihiko Muromatsu

Extraction behaviour of copper(II) and silver(I) with a thiacrown ether carboxylic acid, 2-(3,6,10,13-tetrathiacyclotetradec-1-oxy)hexanoic acid

The extraction behaviour of copper(II) and silver(I) with 2-(3,6,10,13-tetrathiacyclotetradec-1-oxy)hexanoic acid (TTCTOHA) was investigated at 25+/-0.1 degrees C and ionic strength of 0.1. The value of the logarithmic distribution coefficient, logK(DR) of TTCTOHA between octan-1-ol and aqueous phases was determined to be 4.13. Copper(II) was extracted with TTCTOHA into octan-1-ol as CuL(2), where L represents the anionic species of TTCTOHA. The logarithmic extraction constant, logK(ex(10)), was determined at -7.42. Silver(I) was extracted with TTCTOHA into octan-1-ol as AgL and Ag(2)L(2). The logarithmic distribution constant, logK(DC), of AgL was estimated to be 0.49. On the other hand, silver(I) was extracted into 1,2-dichloroethane as AgL and the logarithmic extraction constant, logK(ex(10)), was determined to be -2.24.

Liquid-liquid extraction of platinum(II) with cyclic tetrathioethers.

The liquid-liquid extraction of platinum(II) with 12-, 14- and 16-membered cyclic tetrathioethers from chloride solution was studied. Bromocresol Green ion as a counter anion and 1,2-dichloroethane as an extraction solvent were used. The effect of thiourea on the extraction rate of platinum(II) was examined. Platinum(II) was hardly extracted with macrocyclic tetrathioethers in the absence of thiourea because of the slow extraction rate. The extraction rate of platinum(II) was considerably enhanced by the addition of thiourea. The extraction rate of platinum(II) with 16-membered cyclic tetrathioether was faster than that with 12- and 14-membered ones. Platinum(II) was quantitatively extracted with 16-membered cyclic tetrathioether into 1,2-dichloroethane within 5 h in the presence of thiourea.

Extraction behaviour of silver(I) with some cyclic tetrathioethers

Abstract The extraction behaviour of silver(I) with 12-, 13-, 15- and 16-membered cyclic tetrathioethers (n-ane-S4, where n represents the total number of carbon and sulphur atoms in the cyclic ligand ring) was examined stoichiometrically using the picrate ion (Pic−) for the formation of the ion pair and chloroform and 1,2-dichloroethane as solvents. The composition of the extracted species and the extraction constant were determined. Silver(I) was extracted with these four ligands (L) into chloroform and 1,2-dichloroethane as the ion-pair compound [AgL]+Pic−. The extracted species with these four ligands is different from that previously reported for 14-ane-S4, [AgL2]+Pic−.

Liquid-liquid extraction of copper(II) with cyclic tetrathioethers

Abstract Liquid-liquid extraction of the divalent metal ions manganese(II), cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) with 1,4,8,11-tetrathiacyclotetradecane was examined using the tetraphenylborate ion (TPB − ) for the formation of the ion pairs. Copper(II) was quantitatively extracted into 1,2-dichloroethane, whereas the other metals were hardly extracted. The extraction behaviour of copper(II) with 12–16-membered cyclic tetrathioethers ([ n ]aneS 4 , where n represents the total number of carbon and sulphur atoms int he cyclic ligand ring) was examined. Chloroform and 1,2-dichloroethane were used as extraction solvents. The order of the extractability of copper(II) was as follows: [15]aneS 4 > [16]aneS 4 > [14]aneS 4 > [13]aneS 4 > [12]aneS 4 > at 2.5 × 10 −4 M of ligands, [16] aneS 4 > [15]aneS 4 > [14]aneS 4 > [13]aneS 4 > [12]aneS 4 at 2.5 × 10 −5 M of ligands. The extracted species were examined at ligand concentrations higher than 2.5 × 10 −4 M. Copper(II) was extracted with [13]aneS 4 and [16]aneS 4 as [CuL 2 ] 2+ (TPB − ) 2 and [CuL 4 ] 2+ (TPB − ) 2 depending upon the relative concentration of the ligand to copper(II). Where L represents cyclic tetrathioethers. The extracted species with [14]aneS 4 and [15]aneS 4 were [CuL 2 ] 2+ (TPB − ) 2 and [CuL 4 ] 2+ (TPB − ) 2 , respectively. In case of [12]aneS 4 , the following three species were observed depending upon concentrations of the ligand and TPB − : [CuL 2 (OH)] + TPB − , [CuL 2 ] 2+ (TPB − ) 2 and [CuL 4 ] 2+ (TPB − ) 2 .

Liquid-liquid extraction of copper(I) by cyclic tetrathio ethers

Abstract The liquid-liquid extraction of copper(I) with 12-, 13-, 15- and 16-membered cyclic tetrathio ethers ([ n ]aneS 4 , where n represents the total number of carbon and sulphur atoms in the cyclic ligand ring) was examined stoichiometrically using picrate ion (Pic − ) for the formation of the ion pair. Copper(I) was extracted with four ligands (L) into 1,2-dichloroethane as the ion-pair compound, [Cu(I)L] + Pic − . The extraction constant, K ex , with each ligand was determined. As the ring size of cyclic tetrathio ethers increases, the log K ex values, including that previously reported for [14]aneS 4 , increase from 7.7 to 9.4. The value of Δ log K ex , which represents the increase in log K ex due to the addition of one carbon atom to the macrocyclic ring, was large between [13]aneS 4 and [14]aneS 4 (Δ log K ex =1.0) and small between [14]aneS 4 and [15]aneS 4 (Δ log K ex =0.1).

Synthesis of thiacrown ether carboxylic acids and their characteristics as extractants for metal ions

Abstract Two thiacrown ethers with pendant carboxylic acid groups, 3,6,10,13-tetrathiacyclotetradec-1-oxyacetic acid (TTCTOAA) and 2-(3,6,10,13-tetrathiacyclotetradec-1-oxy)hexanoic acid (TTCTOHA), were synthesized and their proton dissociation constants (p K a ) were determined potentiometrically at 25 ± 0.1°C and an ionic strength of 0.1. The p K a values of TTCTOAA and TTCTOHA were 3.97 and 4.05, respectively. The characteristics of thiacrown ether carboxylic acids as extraction reagents for metal ions were examined and compared with those of the neutral thiacrown compound 1,4,8,11-tetrathiacyclotetradecane (TTCT) in the presence of picrate ion for the formation of the ion pair. 1,2-Dichloroethane was used as the extraction solvent. The extractability of metal ions with TTCTOAA was very low. In the case of TTCTOHA, copper(II), silver(I) and copper(I) were extracted into 1,2-dichloroethane. The extractability of silver(I) and copper(I) was lower than that with TTCT and picrate ion. The extraction percentage of silver(I) with TTCTOHA was significantly higher than that of copper(I), whereas hardly any difference in extractability with TTCT was observed between silver (I) and copper(I). Although copper(II), a borderline Lewis acid, was weakly extracted with TTCT and picrate ion, it was extracted well (over 90%) with TTCTOHA into 1,2-dichloroethane. The extraction of copper(II) and silver(I) with TTCTOHA into different organic solvents was examined. The extractability of copper(II) and silver(l) decreased in the order 1-octanol ≈ benzene >; 1,2-dichloroethane and 1-octanol >; 1,2-dichloroethane >; benzene, respectively.

NEW DETECTION METHOD OF α-, β-, AND γ-AMINO ACIDS COUPLED WITH AN ON-LINE PHOTO-CHEMICAL OXIDATION AND TRIS(2,2′-BIPYRIDINE)-RUTHENIUM(III) CHEMILUMINESCENCE

ABSTRACT A new postcolumn detection method for amino acids is proposed. The method is based on the oxidation of analytes to oxalate with subsequent chemiluminescent detection using tris(2,2′-bipyridine)ruthenium(III). A mixing solution of eluate and periodate as an oxidizing agent is delivered to a reaction coil, which is then irradiated with UV light to accelerate the oxidative reaction. The effects of pH, UV irradiation time and temperature on the oxidative reaction were examined. Detection limits of eleven kinds of amino acids in high-performance liquid chromatography ranged from 1 pmol of threonine and phenylalanine to 40 pmol of glycine at a signal-to-noise ratio of 3.

New Chemiluminescence Detection Method of Aliphatic Conjugated Dienes Using Electrogenerated Tris(2,2′‐Bipyridine)Ruthenium(III)

Abstract Tris(2,2′‐bipyridine)ruthenium(III) will undergo a chemiluminescent reaction with an appropriate reducing agent. Organic compounds with conjugated double bonds such as 2,4‐hexadiene and α‐terpinene were tested between a pH of 3 and 7 and found to act as chemiluminescent reducing agents. The chemiluminescent intensities for aliphatic conjugated dienes were dependent upon the pH at which the chemiluminescence reaction was conducted, and intense chemiluminescence was observed in acidic aqueous solutions. It has been shown that the electron‐withdrawing/donating character of the functional group attached to the carbon atoms building conjugated double bonds influences the chemiluminescent efficiency of the reaction. A novel chromatographic method for the determination of aliphatic conjugated dienes based on the chemiluminescent reaction was developed. The lowest detection limit of 0.6 pmol in high‐performance liquid chromatography was found for 2,5‐dimethyl‐2,4‐hexadiene at a signal‐to‐noise ratio of 3. This work (partly) was supported by the Sasakawa Scientific Research Grant from The Japan Science Society.

Studies on the reactions of PtCl2en, cis-Pt(NH3)2Cl2 and their aqua species with adenosine, deoxyadenosine and adenine using ion-pair HPLC

Abstract The reactions of PtCl 2 en or cis -Pt(NH 3 ) 2 Cl 2 and their aqua species with adenine and adenosine were studied by means of ion-pair HPLC. From the chromatograms, it was found that the first binding site of Pt(II) was the N(7) site of adenine under both acidic and neutral conditions. The rates of Pt(II) binding at the (N7) site of adenosine and deoxyadenosine were measured. The rate constants, k 1 , were obtained for the reactions of PtCl 2 en or cis -Pt(NH 3 ) 2 Cl 2 with adenosine and deoxyadenosine at pH 3 and 7 over the temperature range 9–25 °C. The k 1 values were 6.8–7.7 × 10 −4 dm 3 mol −1 s −1 at 25 °C. For the aqua species, the rate of [ cis -Pt(NH 3 ) 2 ClH 2 O] + with adenosine N(7) was measured. The rate constants, k 2 which were found to be smaller than those of hydrolysis, k h , were calculated at pH 3 over the temperature range 25–40 °C. The k 2 value obtained at 25 °C was 1.1 × 10 −2 dm 3 mol −1 s −1 , 15 time larger than k 1 . The activation parameters were also calculated.