Relativistic effect of iodine in 13C NMR chemical shifts of iodomethanes from quantum chemical calculations within the framework of the full four-component relativistic Dirac—Coulomb scheme

Autor: Leonid B. Krivdin, D. O. Samultsev, Yu. Yu. Rusakov
Rok vydání: 2015
Předmět:
Zdroj: Russian Chemical Bulletin. 64:2756-2762
ISSN: 1573-9171
1066-5285
DOI: 10.1007/s11172-015-1221-y
Popis: 13C NMR shielding constants (chemical shifts) of iodomethanes were calculated within the framework of the full four-component relativistic Dirac—Coulomb scheme. As the number of iodine atoms in the molecule increases, the relativistic counterpart of the 13C NMR chemical shift increases from a few tens to several hundreds of ppm. Calculations of 13C NMR chemical shifts of organoiodine compounds should be performed at the relativistic level using relativistic Dyall’s basis sets dyall.vXz and dyall.xvXz (x = a, c, ac, ae; X = 2, 3, 4) of at least triple-zeta quality or at the correlated non-relativistic level taking into account relativistic corrections. Solvent effects are not of prime importance; however, taking into account the solvent corrections causes the mean absolute error of determination of the 13C NMR chemical shifts to decrease by 1—2 ppm.
Databáze: OpenAIRE
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