Effect Of Ion Pair Formation Research Articles

Ion pair formation effects in the reversible electroreduction of nitrobenzene in N,N-dimethylformamide

Ion pair formation effects in the reversible electroreduction of nitrobenzene in N,N-dimethylformamide

The Effects of Ion-pair Formation on the ESR Spectra of the Anion Radicals of 4-Nitropyridine N-Oxide and 4-Nitropyridine

Abstract The effect of potassium ion-pair formation on the ESR spectra of the anion radicals of 4-nitropyridine and its N-oxide (4NPO) was studied at various temperatures lower than room temperature. The hyperfine splitting constant values due to hydrogen, nitrogen, and potassium nuclei were determined by applying the simulation technique. The above value arising from the potassium nucleus, decreased with a decrease in the temperature. Molecular orbital calculations covering the whole system of the 4NPO−–M+ ion pair and employing the McLachlan modification for the spin-density calculation were carried out in order to discuss the configuration of the ion pairs and the temperature dependence of the hyperfine coupling constants. It was reasonably concluded that an alkali metal cation occupies the C2 axis of the anion radicals and is in contact with the nitro-group oxygen atoms (the symmetry of the ion pairs is C2v.). The temperature dependence of the hyperfine splitting constants was explained using the vibrational model of Atherton and Weissman.

Ion pair formation effects in the reversible electroreduction of nitrobenzene in N,N-dimethylformamide

From polarographic measurements pKass values of ion pairs formed by the nitrobenzene radical anion N− and cations M+ have been estimated. Application of the function (R+δ)−1 distinctly improved the empirical relation between E1/2ipf and ionic potentials verifying the assumption of the considerable influence of solvation effects on ion pair formation. This is also supported by a thermocycle treatment of solvation and association of ions and ion pairs.

EPR Studies of the Rotation of Phenyl Rings in Benzophenone Ketyls

Temperature dependence of the EPR spectra of various benzophenone ketyls and related compounds was studied in detail. Complete ranges of spectra from the spectra in the limit of rapid rotation of phenyl ring to the spectra in the limit of slow rotation of phenyl ring were obtained for benzophenone free ions and ion-pair ketyls and explained in terms of Freed–Fraenkel relaxation matrix theory, using a four-jump model. Unequivalent ortho and meta hyperfine splittings, rates, and activation energies for the rotation of phenyl rings were determined. Effects of ion-pair formation and higher aggregation on the rates of rotations of rings have been studied in several systems.

Effect of Ion-Pair Formation on the Rate of Aromatic Substitution.

Effect of Ion-Pair Formation on the Rate of Aromatic Substitution.

A General Equation of the Polarographic Wave Applicable to Solvents of Low Dielectric Constant; Effect of Ion-pair Formation on Half-wave Potentials

A General Equation of the Polarographic Wave Applicable to Solvents of Low Dielectric Constant; Effect of Ion-pair Formation on Half-wave Potentials