Alexander V Kisin

Publications (3)7.47 Total impact

• Article: Structural trends of (29) Si-(1) H spin-spin coupling constants across double bond.

  Yury Yu Rusakov, Leonid B Krivdin, Valentina M Nosova, Alexander V Kisin, Valentin G Lakhtin
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  ABSTRACT: The calculations of geminal and vicinal (29) Si-(1) H spin-spin coupling constants across double bond in 15 alkenylmethylsilanes and alkenylchlorosilanes were carried out at the second-order polarization propagator approach level in a good agreement with experiment. Two structural trends, namely, (i) the geometry of the coupling pathway and (ii) the effect of the electrowithdrawing substituent, have been interpreted in terms of the natural J-coupling analysis within the framework of the natural bond orbital approach. Thus, the marked difference between cisoidal and transoidal (29) Si-(1) H spin-spin coupling constants across double bond was accounted for the delocalization contributions including bonding and antibonding Si-C and C-H orbitals, whereas the chlorine effect was explained in terms of the steric contributions including bonding Si-Cl orbitals. Copyright © 2012 John Wiley & Sons, Ltd.
  Magnetic Resonance in Chemistry 08/2012; 50(10):665-71. · 1.44 Impact Factor
• Article: Benchmark calculations of (29) Si-(1) H spin-spin coupling constants across double bond.

  Yury Yu Rusakov, Leonid B Krivdin, Valentina M Nosova, Alexander V Kisin
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  ABSTRACT: Benchmark calculations of geminal and vicinal (29) Si-(1) H spin-spin coupling constants across double bond in three reference alkenylsilanes have been carried out at both DFT and SOPPA levels in comparison with experiment. At the former, four density functionals, B3LYP, B3PW91, PBE0 and KT3, were tested in combination with five representative basis sets. At the latter, three main SOPPA-based methods, SOPPA, SOPPA(CC2) and SOPPA(CCSD), were examined in combination with the same series of basis sets. On the whole, the wavefunction methods showed much better results as compared to DFT, with the most efficient combination of SOPPA/cc-pVTZ-su2 characterized by a mean absolute error of only 0.4 Hz calculated for a set of nine coupling constants in three compounds with a sample span of around 40 Hz.
  Magnetic Resonance in Chemistry 03/2012; 50(4):278-83. · 1.44 Impact Factor
• Article: Structure of complexes formed by dissolution of palladium diacetate in methanol and chloroform. In situ NMR study.

  Valentina M Nosova, Yuri A Ustynyuk, Lev G Bruk, Oleg N Temkin, Alexander V Kisin, Pavel A Storozhenko
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  ABSTRACT: The behavior of palladium diacetate cyclic trimer [Pd(OAc)(2)](3) (1) upon its dissolution in methanol and wet chloroform was studied by (1)H and (13)C NMR including 2D-HSQC and 2D-DOSY techniques. Upon dissolution, trimer 1 reacts with methanol and is completely transformed first into the methoxo complex Pd(3)(μ-OMe)(OAc)(5) (2), which already at -18 °C undergoes a slow exchange of second bridging acetate ligand between the same palladium atoms to form the symmetric dimethoxo complex Pd(3)(μ-OMe)(2)(OAc)(4), the maximum relative concentration of which reaches 20-30 mol % of initial loading trimer 1. Along with the dimethoxo complex, both soluble and insoluble polynuclear palladium clusters are gradually formed at -18 °C, and their total amount reaches up to 60% of the starting Pd(2+) loading. The increase of temperature to 27 °C results in the reduction of palladium(II) to Pd metal by methanol, which is oxidized and transformed into formaldehyde hemiacetal and methyl formate. Upon dissolution in wet chloroform, trimer 1 is reversibly hydrolyzed to the hydroxo complex Pd(3)(μ-OH)(OAc)(5) (10) in ratio 1/10 ≈ 3/1. The temperature decrease and addition of acetic acid shift the equilibrium in this system toward trimer 1, and addition of water shifts it in the opposite direction. Addition of methanol to the equilibrium mixture of 1 and 10 results in the fast exchange of bridging acetate in trimer 1 by the μ-OMe group. Substitution of the μ-OH ligand by μ-OMe in 10 occurs in parallel but more slowly. Complex 2 formed in both cases is more stable in chloroform than in methanol.
  Inorganic Chemistry 09/2011; 50(19):9300-10. · 4.60 Impact Factor