Electro-chromatography in the study of ions

Summary Quantitative estimation of small amounts of nickel (after electrophoretic movement) from the band on the filterpaper is possible with the help of the photo-electric scanner. The error is within ±5%.

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Zusammenfassung Die quantitative Bestimmung kleiner Mengen Nickel ist möglich durch Papierelektrophorese und anschließende photometrische Auswertung der Papierstreifen. Die Ergebnisse sind auf ±5% genau.

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Part III, See H. G. Mukerjee: Z. analyt. Chem. 167, 182 (1959).     

Electro-chromatography in the study of ions

Summary Change of concentration of electrolyte such as sodium chloride, potassium chloride, ammonium chloride and potassium bromide has a marked effect on the direction of migration of Cd. A very cheap set incorporating a number of Durrum'S units suitable for separation of a large number of different types of mixtures of ions has been devised.     

Electro-chromatography in the study of ions

Summary The migration distance in the case of a fast moving ion increases with time, as is to be expected, while in the case of a slow moving ion, it is nearly independent of time. Names of fast moving and slow moving ions and carrier electrolytes are shown in a table.     

Electro-chromatography and the movement of complex ions

It is apparent that, in electro-chromatographic separations, the change of area undergone by the initial spot of test solution plays a part in the final interpretation of results almost as important as the actual movement of the centre of the spot.Several interesting facts have emerged from this research concerning the role of the carrier electrolyte on tlie movement, the spot size, and the stability of complex salts.     

Electro-chromatography in the separation of ions : Separation of third group metals

The ionic migration and migration sequences of the ions of group III, Fe⁺³, Cr⁺³, A1⁺³, Be⁺², Ti⁺⁴, Zr⁺⁴, Th⁺⁴, UO₂⁺²havce been determined in a number of common electrolytes. Owing to their similar behaviour towards ionic migration, besides separations from their binary and ternary mixtures, only a few separations from quaternary mixtures as Zr-Th-U-Be, Zr-Th-U-Al, Zr-Th-Al-Be, Zr-U-Al-Be, Ti-Th-U-Bc, Ti-Th-U-Al, U-Zr-Al-Fe and U-Th-Al-Fe are possible.     

Electro-chromatography in the separation of ions : Part II. Separation of precious metals

An electrochromatographic study of the migration rates and sequences of the precious metals, as Pt⁺⁴, Os⁺⁴, Ir⁺⁴, Ru⁺³, Rh⁺³, Au⁺³ and Pd⁺², on paper strips, reveals that quite a large number of electrolytes effectively separate in distinct zones at least four ions present in microgram amounts in a mixture, when the voltage is maintained at 150 V for 5 hours.     

Electro-chromatography in the separation of ions : Separation of copper and tin group metals

The ionic migration and hence the migration sequences of the ions of the copper and the tin groups have been determined in a number of common electrolytes which act as complexing agents. Separation of several three,- four- and five-coniponent mixtures of copper group elements has been effected. Of the electrolytes, hydrochloric acid, sodium chloride and potassium chloride, the last gives the best and most complete separation of all the copper group ions from a mixture, a potential of 150 V being maintained for 5 h. The metals of the tin group cannot be separated completely from each other under the experimental conditions, only separation from binary mixtures is possbble.     

Electro-chromatography in the separation of ions : Part III. Separation of silver group metals

The migration sequences of silver group ions Ag⁺, Hg₂⁺², Pb⁺²and Ti⁺ have been studied in a number of complex-forming electrolytes. Based on the migration sequences, the ions in a mixture can be separated into distinct zones using a decinormal solution of sodium chloride, potassium chloride or potassium cyanide as the electrolyte. The sequence is Hg — Ag— Pb—Ti, while in KCN at pH 7.0 the sequence becomes Ag—Hg—Pb—Ti.     

Electrochromatography in the study of ions

Summary Bismuth can be quantitatively separated from Hg, Pb, Cu and Cd by paper electrophoresis and from the band on the filter paper, quantitative estimation of Bi is possible with the help of the photo-electric scanner. The error lies within ±5%.

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Zusammenfassung Die quantitative Bestimmung von Wismut und seine Abtrennung von Hg, Pb, Cu und Cd kann durch Papierelektrophorese und anschließende photoelektrische Auswertung der Papierstreifen erfolgen. Der Fehler ist kleiner als ±5%.

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Part IV: See H. G. Mukerjee: Z. analyt. Chem. 184, 170 (1061).

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The abstract of the paper has been communicated, for publication in the Proceedings of the 50th Indian Science Congress.     

Even-electron ions: a systematic study of the neutral species lost in the dissociation of quasi-molecular ions

The collision-induced dissociations of the even-electron [M + H](+) and/or [M - H](-) ions of 121 model compounds (mainly small aromatic compounds with one to three functional groups) ionized by electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) have been studied using an ion trap instrument, and the results are compared with the literature data. While some functional groups (such as COOH, COOCH(3), SO(3)H in the negative ion mode, or NO(2) in both the positive and negative ion modes) generally promote the loss of neutrals that are characteristic as well as specific, other functional groups (such as COOH in the positive ion mode) give rise to the loss of neutrals that are characteristic, but not specific. Finally, functional groups such as OH and NH(2) in aromatic compounds do not lead to the loss of a neutral that reflects the presence of these substituents. In general, the dissociation of [M + H](+) and [M - H](-) ions generated from aliphatic compounds or compounds containing an aliphatic moiety obeys the even-electron rule (loss of a molecule), but deviations from this rule (loss of a radical) are sometimes observed for aromatic compounds, in particular for nitroaromatic compounds. Thermochemical data and ab initio calculations at the CBS-QB3 level of theory provide an explanation for these exceptions. When comparing the dissociation behaviour of the even-electron [M + H](+) and/or [M - H](-) ions (generated by ESI or APCI) with that of the corresponding odd-electron [M](+) ions (generated by electron ionization, EI), three cases may be distinguished: (1) the dissociation of the two ionic species differs completely; (2) the dissociation involves the loss of a common neutral, yielding product ions differing in mass by one Da, or (3) the dissociations lead to a common product ion.     

Computational study of isopropylbenzenium ions

A theoretical investigation of the isopropylbenzenium ion system has been carried out with structures determined with B3LYP. Energies are calculated with the high accuracy composite methods, G3 (G3B3) and CBS (CBS-QB3). The main goal has been to resolve the following issue: Are there any stable ion π-electron complexes of the type C(6)H(6)/C(3)H(7)(+) or C(6)H(7)(+)/C(3)H(6) in this system? Two minimum points on the potential energy surface (PES) corresponding to benzenium ion/propene complexes were found. Due to free internal rotation, they represent only one species. The barrier for forming an isopropylbenzenium ion from the complex is low, so the lifetime will be short. Computation of the IR spectrum of the complex shows that there is a very intense absorption line due to C-H stretching, in an otherwise empty region, that may be used to identify the complex, if present. No stable C(6)H(6)/C(3)H(7)(+) complex was found, but a quasi-stable species structurally corresponding to the earlier described stable C(6)H(6)/C(4)H(9)(+) complex was observed. A simplistic explanation why the benzene/isopropyl cation, in contrast to benzene/tert-butyl cation, does not form a stable ion/π-electron complex is given.     

A collisional activation study of ions generated from the molecular ions of 2-phenoxyethyl halides

Collisional activation spectra of ions generated from phenol, [2,2,2]oct-2-en-5,7-dione and site specifically deuterium labelled 2-phenoxyethyl halides, , have shown that 2,4-cyclohexadienone and phenol ions are distinct stable species in the gas phase for ≥ 10^?5 s.     

A computational study of tert-butylbenzenium ions

A computational study of tert-butylbenzenium ions has been performed. Structures and energies of the various isomers and the transition states for their interconversions have been determined. The existence of a stable π-electron complex (called A1) between a tert-butyl cation and a benzene molecule has been confirmed. Other minimum points on the potential energy surface corresponding to π-complexes were found, but the barriers for transforming these complexes into the stable π-electron complex A1 are so low that the transformation into the stable structure can take place at all temperatures. The structures were evaluated at the DFT-B3LYP level of theory. The energies were evaluated with the Gaussian-3 (G3B3) and CBS (CBS-QB3) composite methodologies. A discussion of published experimental data in view of the computational results is given. It is pointed out that it should be possible to show the presence of the π-complex by IR spectroscopy. The computations show that the π-complex has a very strong IR band in an otherwise empty region.     

An mo study of the substituent effect in benzene radical ions

The effect of various types of substituents (X=OH, CH₃, CN, SiH₃) in benzene radical cations and anions have been investigated using INDO-SCF computations with and without π conjugation admitted between the substituent and the adjacent substrate. The inductive effect of the substituent has been found to play a minor role in determining the more stable configuration, the latter being determined in all cases investigated by the π conjugative interactions. A OEMO analysis of such interactions provides a better understanding of the key factors controlling the configuration preferentially stabilized in the various cases.     

Theoretical study of the borane and diborane positive ions

Summary We describe the geometric, electronic and energetic (H _f) properties of B₂H ₆ ⁺ and BH ₃ ⁺ . Comparisons with experimental measurements have also been made with borane, diborane, BH, BH⁺ and BH ₂ ⁺ . All the theoretical calculations have been performed with various basis sets: 6-31G, 6-31G and 6-31⁺G (2d,f). The geometry optimizations are done at the SCF (RHF or UHF), MP2 and MP4 levels.