Photoelectron spectra andab initio calculations of the electronic structure of amino-n-sulfenyl chlorides

The electronic structure of some amino-N-sulfenyl chlorides and related compounds is studied by photoelectron spectroscopy and ab initio calculations. Similar values of IP(n _S ) and IP(n _N ) and the total energy minimum indicate that in stable conformations the n _S and n _N orbitals are orthogonal. These conformers are characterized by an effective n_N-σ _S-Cl ^* interaction. The relationship between the intramolecular shift of charge and ionization potential values and the spatial structure of amino-N-sulfenyl chlorides is analyzed. A. E. Arbuzov Institute of Organic and Physical Chemistry, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 2, pp. 69–73, March–April, 1994. Translated by L. Smolina     

Sorption–Spectrometric Determination of Palladium in Chloride Solutions

A sorption–spectrometric method was developed for the determination of palladium in solutions of complex composition using cellulose filters impregnated with trioctylamine with the subsequent formation of the colored compound of palladium with 4-(2-pyridylazo)resorcinol on the filter. It was demonstrated that conditions for the preconcentration of palladium coincide with conditions for the formation of colored compounds (green and red forms of palladium complexes) in the sorbent phase. The highest selectivity is observed for the formation of the green form; in this case, the determination of palladium is not affected by the interference from large amounts of concomitant elements (macrocomponents of ores). Palladium was determined on filters by diffuse reflectance spectrometry with the calculation of chromaticity characteristics and by a test scale. The detection limits were 0.5 (green form) and 0.3 (red form) g of palladium on the filter. High precision of results of the determination of palladium (RSD < 5%) is attained in a wide range of its concentrations.     

Recyclization of tetranitrodibenzo-18-crown-6 and tetranitrodibenzo-24-crown-8 into monobenzocrown ethers

The benzo-9-crown-3 and benzo-12-crown-4 derivatives are formed by reaction of tetranitrodibenzo-18-crown-6 and tetranitrodibenzo-24-crown-8, respectively, with sodium methoxyethoxide in DMSO at 20C.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1474–1476, November, 1990.     

Electrical conductivity of solutions of the LiIO3-HIO3-H2O system

The electrical conductivity of aqueous LiIO₃ solutions and solutions of the LiIO₃-HIO₃-H₂O system is measured over a wide range of compositions at 25, 50, and 75°C. Isothermal surfaces of electrical conductivity are mapped, and the activation energies of conductivity are calculated. The conductivity isotherms in the LiIO₃-H₂O and HIO₃-H₂O boundary binary systems and in mixed solutions along sections with fixed electrolyte ratios each have a maximum as a function of electrolyte concentration. It is assumed that structure reorganization occurs in solutions in the concentration range corresponding to the peak conductivity. Proton migration features in the solutions in question are considered.     

Existence and uniqueness theorems for A -regular generalized solutions of the first boundary-value problem for (A,674-01674-01674-01) — Elliptic equations

For second-order quasilinear degenerate elliptic equations, having the structure of -elliptic equations in a bounded domain Rⁿ, n2, one establishes theorems of existence and uniqueness for the generalized solutions of the first boundary-value problem, bounded together with their A -derivatives of first order and also of first and second order. The case of linear second-order -elliptic equations are separately considered.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 115, pp. 83–96, 1982.     

Synthetic analogs of active centers of iron-sulfur proteins: Reactions with phosphates

The interaction of synthetic analogs of active centers of iron-sulfur proteins with phosphates of different structures was studied. It was shown that the process involves ligand exchange and obeys the first-order reaction kinetic equation. The most rapid exchange occurred with the most acidic compound diphenyl phosphate.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan' Scientific Center, Russian Academy of Sciences, 420083 Kazan'. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2301–2305, October, 1992.     

Calculated structures of asymmetric modifications of cyanospinels

Structural mechanisms of formation of low-symmetry phases of cyanospinels are described in terms of the phenomenological theory of phase transitions. These are examined for transitions from a spinel structure to two cubic and four rhombohedral phases, induced by automorphic irreducible representations 9-2 and 9-3. Atomic coordinates and the symmetry types of occupied positions in asymmetric phases are determined. Criteria for discrimination between the two as well as between the four phases are formulated. The structures of complex cyanides Tl₂Zn(CN)₄ , K₂Zn(CN)₄, K₂Hg(CN)₄, and Rb₂Hg(CN)₄ are calculated. The displacements and irreducible representations inducing transitions from spinel structures to these phases are determined. Novocherkassk State Technological University. Translated fromZhumal Struktumoi Khimii, Vol. 35, No. 5, pp. 41–49, September–October, 1994. Translated by L. Smolina