[en] Solution passed through a small capillary tube at several kilovolts relative to its surroundings is electrosprayed into a bath gas at slightly above atmospheric pressure to form a dispersion of ions that expands into vacuum through a small sonic orifice. A portion of the resulting supersonic free jet passes through a skimmer carrying ions into a quadrupole mass spectrometer. Previously reported results were obtained with positive ions formed when the capillary was at a positive potential. The present report concerns operation with the capillary at a negative potential to produce negative ions. As in the case of operation in the positive mode ions with varying degrees of solvation can be obtained from a variety of solute species including complex and nonvolatile organic molecules. No fragmentation of parent species is observed as long as electrical discharge is avoided in the gas phase. The presence of electron scavengers in the bath gas raises the potential at which discharge phenomena begin. Differences and similarities relative to operation in the positive mode are discussed

[en] The proton-ligand stability constants of 5-sulphosalicylic acid and stability constant of its complexes with UO₂(II) have been studied by potentiometric and spectrophotometric techniques at various ionic strengths (27deg+-0.1degC). The values of pK (proton-ligand stability constants) and Log k (Metal-ligand stability constants) at different ionic strengths are utilised to estimate the thermodynamic, stability constants at zero ionic strength and to know the exact nature of complexation equilibria. (author)

[en] The complexation studies of Cu(II) and UO₂(II) with o-cresotic and 1-hydroxy 2-naphthoic acids alongwith their acetyl and benzoyl derivatives have been carried out spectrophotometrically at 30+-0.5degC. The measurements indicate that Cu(II) and o-cresotic acid (as well as its acetyl and benzoyl derivatives) react in 1:1 ratio in the pH range 5-5.2 and 1:2 ratio at pH 6-6.2, whereas copper(II) and 1-hydroxy 2-naphthoic acid (as well as its acetyl and benzoyl derivatives) react in 1:2 ratio at pH values > 10. With UO₂(II) ion, the above mentioned ligands indicate the formation of only 1:1 complex in the pH range 2-10. The stability constants of the complexes have been calculated by two alternate procedures. (author)

No abstract available

[en] Cuprous thiocyanate (p-type semiconductor) is found to adsorb thiocyanated cationic dyes to yield high photoresponses in aqueous KCNS. The method of preparation and the performance of dye-sensitized CuCNS photocathodes are discussed. Electrolytic photocells with semiconductor electrodes are attracting attention as economical devices for the conversion of solar energy. The additional advantage of these systems is the possibility of extending the spectral response by sensitization with dyes. It is also known that the dye-sensitized (DS) photocurrent is rather insensitive to impurities and defects in the semiconductor; polycrystalline and amorphous materials with large bandgaps when sensitized yield high photocurrents. The sensitization is effective only if the dye is absorbed at the semiconductor surface. Thus, to produce practically useful DS cells, it is necessary to search for systems where the dye adsorption is optimized. The authors have found that cuprous thiocyanate (a p-type semiconductor) readily adsorbs cationic dyes when CNS- is the anionic ligand. In this paper, they describe observations on DS CuCNS electrodes in aqueous KCNS

[en] The adsorption of cesium on manganese dioxide from aqueous solutions was studied in relation to pertinent variables such as shaking time, pH, composition of aqueous solutions, mass of adsorbent (10 mg - 1 g) and concentration of adsorbate (10^-6 - 5x10^-3M) using a radiotracer technique. The influence of various anions and cations on cesium adsorption was examined. The distribution coefficient of a variety of other elements was determined under similar conditions. The adsorption of cesium obeys a Freundlich-type isotherm over the entire concentration range investigated, whereas the Langmuir-type isotherm is followed at moderate concentrations only. (author)

[en] Mixed ligand chelates of the 1:1 trivalent lanthanoids-EDTA, HEDTA and NTA chelates-1, 2-Dihydroxybenzene (Pyrocatechol) have been investigated at 35degC and 0.2 M ionic strength maintained by NaC10₄. The formation of mixed ligand chelates has been found in all cases. The formation of mixed ligand chelates with EDTA shows the coordination number of lanthanoids to be eight, while the mixed ligand chelates with HEDTA and NTA shows the coordination number to be seven and six respectively. The stability constants of mixed ligand chelates are smaller than the binary complexes. The order of stability constants with respect to primary ligands follows the order NTA>HEDTA>EDTA. With respect to metal ions the stability constants increases with the decrease in ionic radii such as Gd< Er< Yb. (author)

[en] Isotopic exchange behaviour of nickel xanthate is studied in the presence of aniline and three isomeric toluidines at 18degC. The effect of base concentration is also studied on the exchange rate. The results show that the complex is labile in the kinetic sense in the presence of aniline meta and para toluidines. The rate of exchange increases with and para toluidines. The rate of exchange increases with increase in concentration of the base. The complex displays inert behaviour in the presence of o-toluidine and it is ascribed to dominant steric effect. (author)

[en] Recent research accomplishments that elucidate the bonding and reactivity of the actinides are highlighted in this review. Improved syntheses of protactinium and transplutonium metals and compounds have led to determination of physical properties that reveal effects of 5f interactions. Thermodynamic measurements on metals, aqueous ions, and oxides have yielded more systematic understanding of the chemistry of the entire actinide series. Advances in bonding include the preparation of new organoactinide compounds with strong sigma and π metal-carbon and metal-hydrogen bonds; the development of new actinide complexing, sequestering, and extracting agents; and the study of chemical consequences of radioactive decay on oxides and halides. New techniques that impact actinide chemistry are laser fluorescence and photochemistry, radiocoulometry, and pulse radiolysis. Progress has also been made in outlining the basic chemical behavior of the heaviest actinides and the transactinides. (orig.)

[en] The preparation of sodium tetrachloronitridotechnetate Na[sup(99m)TcNCl₄] is described. This complex may be used for the preparation by a substitution route of sup(99m)Tc-radiopharmaceuticals containing a Tc-nitrido(TcN) group. The labelling procedure was demonstrated by the preparation of [sup(99m)TcN]MDP, [sup(99m)TcN]DTPA and [sup(99m)TcN]cysteine. Biological distribution studies in mice of these complexes showed that the presence of nitrido group produced a radiopharmaceutical with different biological behaviour to that produced when conventional reduction methods are used with the same ligand. HPLC studies confirmed that the use of the sup(99m)TcNCl₄^- substitution route produced radiopharmaceuticals of high radiochemical purity. (author)