Quantum chemical calculations of certain compounds of tetra- and pentacoordinated phosphorus by the CNDO method

Conclusions A quantum chemical calculation of six molecules of tetracoordinated phosphorus and five molecules of pentacoordinated phosphorus by the CNDO method permitted an explanation of individual details of the mechanism of certain reactions of these compounds and the variation of their reactivity.Translated from Izvestiya Akademii Nauk SSSR, SeriyaKhimicheskaya, No. 11, pp. 2486–2490, November, 1973.     

Quantum chemical calculations of fluoroethylene molecules by the CNDO and INDO methods

Conclusions A quantum chemical calculation of seven fluoroethylene molecules and two fluorochloroethylene molecules and two fluorochloroethylene molecules by the CNDO and INDO methods has made it possible to explain the experimentally observed change in reactivity and direction of addition reactions at the double bond. The data of a calculation of the relative stability of various isomers also agree with the experimental results.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2199–2202, October, 1973.     

Adsorption of some phosphorus oxy anions on copper

Conclusions The radioactive isotope method was used to study the adsorption of various anions of phosphoric, phosphorous, and hypophosphorous acids on negatively and positively charged copper, and it was shown that the corresponding adsorption values change oppositely to the sums of the absolute values of the charges of all of the atoms of the anion, which were calculated by the CNDO/2 method.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2121–2124, September, 1977.     

Electronic spectra and structure of conjugate acids of carbonyl derivatives of pyrrole

The nature of the ^* transitions in the spectra of neutral molecules of - and -formyl-, acetyl-, and -carbomethoxypyrroles above 210 nm was examined on the basis of an experimental study and calculation by the Pariser-Parr-Pople (PPP) configuration interaction (CI) method. The effect of protonation on the position and intensity of the monotypic transitions was studied. The electronic structures and the energies of the neutral and all of the theoretically possible protonated forms of and -formylpyrroles were calculated within the framework of the CNDO/2 (complete neglect of differential overlap) method. The results of the calculations are in agreement with the experimental data and are in conformity with the greatest energetic advantageousness of protonation of these compounds at the oxygen atom of the carbonyl group.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1221–1228, September, 1977.     

Calculations of magnetic resonance parameters for the protonated nitroxide radical

Electron and magnetic resonance parameters of the protonated H₂NO radical have been calculated by the INDO and CNDO/SP methods for different models. Calculated changes of magnetic resonance parameters on protonation are consistent with experiment. The most appropriate structure has been found to be one in which the proton is in the plane of the radical with r(O?.H⁺) = 1.05 A.Calculated signns of the proton spin density for the models concerned are opposite to those of the spin density on the proton of a ligand involved in the hydrogen bonding for analogous models of hydrogen bond systems formed by the nitroxide radical.In the case of the protonated radical, taking into account the interaction with a solvent molecule leads to more reasonable results for large O?.H⁺ distances.