Showing papers on "Ionic liquid published in 1981"
TL;DR: The light-induced formation of hydrogen in the system H2O-Ru(bpy)32+-mv2+-edta-Pt (mv, inethylviologen) is accompanied by the hydrogenation of mv 2+ to give the 1-methyl-4-(1'-methylpiperidin-4'-yl)pyridinium cation (1) as discussed by the authors.
Abstract: The light-induced formation of hydrogen in the system H2O-Ru(bpy)32+-mv2+-edta-Pt (mv, inethylviologen) is accompanied by the hydrogenation of mv2+ to give the 1-methyl-4-(1'-methylpiperidin-4'-yl)pyridinium cation (1). The production of hydrogen is decreased by factors that favour the formation of this cation. The extent of hydrogenation depends on the pH of the mixture, the amount and type of catalyst present, and the partial pressure of hydrogen during irradiation.
60 citations
TL;DR: In this paper, the enthalpy of pyrrole-2-carboxylate ligand with calcium(II), cobalt (II), nickel (II) and copper(II) cations has been determined by direct calorimetry.
Abstract: Enthalpy of complex formation of pyrrole-2-carboxylate ligand with calcium(II), cobalt(II), nickel(II) and copper(II) cations has been determined by direct calorimetry. By means of the equilibrium constants, Gibbs function and entropy were also obtained. The measurements were carried out in aqueous medium at 25oC and an ionic strength of 1 (NaNO3). The thermodynamic quantities for pyrrole-2-carboxylate, compared with those for pyridine-2-carboxylate obtained previously, lead to the following conclusions. (A) The enthalpy factors which make the metal-pyridinic ligand complexes rather stable are absent in the case of pyrrolic ligand. The absence is probably due to the electronic structure of the pyrrole aromatic ring. (B) The enthalpy data seem to indicate, for the metal complexes of pyrazole and imidazole, a metal-pyridinic nitrogen bond rather than a metal-pyrrolic nitrogen bond.
9 citations
01 Jan 1981
TL;DR: In this paper, it has been suggested that progress in understanding the behavior of concentrated electrolyte solutions will only be made through a consideration of dilute solutions of water in fused salts.
Abstract: This paper is somewhat of a paradox because it is well known that when handling high-temperature solvents, water should be fastidiously avoided! However, it has been suggested recently that progress in understanding the behavior of concentrated electrolyte solutions will only be made through a consideration of dilute solutions of water in fused salts.208, 210 It would appear that this interface is at last being bridged.
6 citations
TL;DR: Binding of aquacopper ion to horse and tuna ferricytochrome c has been investigated over the pH range 2-9 and binding to histidine 33 is consistent with this information, as well as with e.s.r., n.m.r. and visible absorption spectral data.
Abstract: Binding of aquacopper(11) ion to horse and tuna ferricytochrome c has been investigated over the pH range 2-9. Between pH 4 and 7 the principal binding site for horse cytochrome has an intrinsic association constant of 1.8 × 104 1. mol-1 and pKa of 6.5±0.6 at 25oC and ionic strength of 0.1. Binding to histidine 33 is consistent with this information, as well as with e.s.r., n.m.r. and visible absorption spectral data. Other sites also bind copper but with association constants at least a factor of ten smaller. At high pH (> 8) further binding sites predominate.
5 citations
01 Jan 1981
TL;DR: Water is the most important compound in nature and due to its properties and its widespread occurrences, it has much to commend it as a solvent as discussed by the authors. But, this is no longer true at high temperatures.
Abstract: Water is certainly the most important compound in nature. Owing to its properties and its widespread occurrences, it has much to commend it as a solvent. But, this is no longer true at high temperatures. However, molten hydrates are ionic liquids in which the water molecules are one of the components, just as in mixed solvents.
5 citations
TL;DR: In this article, the authors show that 4-phenylbutyl p-nitrobenzenesulfonate solvolyses predominately via the n-route in buffered 2,2,2-trifluoroethanol and 1,1, 1, 3,3,3-hexafluoropropan-2-ol.
Abstract: Kinetic and product studies show that 4-phenylbutyl p-nitrobenzenesulfonate solvolyses predominately via the n-route in buffered 2,2,2-trifluoroethanol and 1,1,1,3,3,3-hexafluoropropan-2-ol; the extent of cyclization in the two solvents is 69 and 99.5%, respectively. In buffered acetic acid, only 3.6% cyclized product is obtained. The advantage of the use of the two fluorinated alcohols for inducing π-participation during solvolysis is thus demonstrated.
5 citations
01 Jan 1981
TL;DR: The role of water in the chemistry and the electrochemistry of melts has received some attention, but the effect of water on transport properties in these media has largely been ignored.
Abstract: The considerable solubility of water in ionic liquids, even up to quite high temperatures, is well established. Commercially available solid compounds generally contain at least traces of water, and totally anhydrous melts may often be obtained only after drastic treatment (see Chapter 12 by White, for example). Although the role of water in the chemistry and the electrochemistry of melts has received some attention, the effect of water on transport properties in these media has largely been ignored.
3 citations
TL;DR: In this article, the vibrational spectra of the Ph3Sn- anion, a pyramidal species with C3V symmetry, and the cationic complexes [M(crown)]+, are reported and assigned.
Abstract: Ionic compounds R+SnPh3-, where R = Me4N, (Ph3P)2N, Na(15-crown-5) or K(18-crown-6), are prepared from alkali metal derivatives, Ph3SnM, by reactions in liquid ammonia which yield the products as yellow crystalline solids, soluble in a weakly basic solvent. N.m.r. and vibrational spectra of the Ph3Sn- anion, a pyramidal species with C3V symmetry, and the cationic complexes [M(crown)]+, are reported and assigned.
3 citations
TL;DR: In this paper, the isothermal compressibilities of molten-salt mixtures are discussed in terms of the hard-sphere fluid theory, and a comparison between the experimental and calculated compressibilities conclusions about the applicability of the Hard-Sphere Fluid Theory (HSFT) to molten salt mixtures is given.
3 citations
TL;DR: A series of nine compounds containing quaternary ammonium and substituted pyridinium cations and the bis(4-methylbenzene-1,2-dithiolato)cobaltate(III) complex anion have been prepared and their ion-pair properties studied by lH n.m. spectroscopy as mentioned in this paper.
Abstract: A series of nine compounds containing quaternary ammonium and substituted pyridinium cations and the bis(4-methylbenzene-1,2-dithiolato)cobaltate(III) complex anion have been prepared andtheir ion-pair properties studied by lH n.m.r. spectroscopy. Their concentration association constants in nitrobenzene at 307 K range from 9 to 20. In the pyridinium series of ion pairs, it is concludedfrom the measured isotropic shift ratios that methyl substituents at the meta and para positions favour a geometry where the anion is tilted towards the ring of the cation but the ortho substituents push the anion away from the ring. In the methyltrioctylammonium ion pair, there is linear correlation between the observed isotropic shift of the N-methyl or the N-methylene protons and the dielectric constant of the solvents (E) from 4.56 to 12.3 for the 0.06, 0.09 and 0.12 M solutions. Its implication is discussed in terms of the formation of the ionic clusters of sufficiently large size.
1 citations
TL;DR: In this article, the homogeneous intramolecular isomerization reactions of all the isomers of [Co(dien)2] (ClO4)3 and [Co (dien)(medien)](ClO 4)3 have been studied at 90°C under atmospheric pressure and conditions of high pressure.
Abstract: The homogeneous intramolecular isomerization reactions of all the isomers of [Co(dien)2] (ClO4)3 and [Co(dien)(medien)] (ClO4)3 (dien, diethylenetriamine; medien, 4-methyldiethylenetriamine) have been studied at 90°C under atmospheric pressure and conditions of high pressure. The isomerization reactions are retarded by an increase in pressure, and for a given starting isomer of each system: the various isomerization processes are affected uniformly. For each system, the same equilibrium isomer distribution was obtained regardless of starting isomer or of the pressure conditions of the experiment. The results are interpreted on the basis of a common mechanism for all isomerizations, involving Co-N bond-rupture followed by rearrangement of the resultant five-coordinate species.
01 Jan 1981
TL;DR: The most important part of these electrochemical investigations on sulfur and sulfide compounds in ionic liquids has been performed in two melts: LiCl-KCl and chloroaluminates as discussed by the authors.
Abstract: The most important part of these electrochemical investigations on sulfur and sulfide compounds in ionic liquids has been performed in two melts: LiCl-KCl and chloroaluminates. Therefore, we shall first focus attention on these two media.