Halogen effect on structure and 13C NMR chemical shift of 3,6-disubstituted-N-alkyl carbazoles
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Halogen effect on structure and 13C NMR chemical shift of 3,6-disubstituted-N-alkyl carbazoles. / Radula-Janik, Klaudia; Kupka, Teobald; Ejsmont, Krzysztof; Daszkiewicz, Zdzislaw; Sauer, Stephan P. A.
I: Magnetic Resonance in Chemistry, Bind 51, Nr. 10, 2013, s. 630-635.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Halogen effect on structure and 13C NMR chemical shift of 3,6-disubstituted-N-alkyl carbazoles
AU - Radula-Janik, Klaudia
AU - Kupka, Teobald
AU - Ejsmont, Krzysztof
AU - Daszkiewicz, Zdzislaw
AU - Sauer, Stephan P. A.
PY - 2013
Y1 - 2013
N2 - Structures of selected 3,6-dihalogeno-N-alkyl carbazole derivatives were calculated at the B3LYP/6-311++G(3df,2pd) level of theory and their 13C NMR isotropic nuclear shieldings were predicted using density functional theory (DFT). The model compounds contained 9H-, N-methyl and N-ethyl derivatives. The relativistic effect of Br and I atoms on nuclear shieldings was modeled using the spin-orbit ZORA method. Significant heavy atom shielding effects for the carbon atom directly bonded with bromine and iodine were observed (~ -10 and ~ -30 ppm while the other carbon shifts were practically unaffected). The decreasing electronegativity of the halogen substituent (F, Cl, Br and I) was reflected in both nonrelativistic and relativistic NMR results as decreased values of chemical shifts of carbon atoms attached to halogen (C3 and C6) leading to a strong sensitivity to halogen atom type at 3 and 6 positions of the carbazole ring. The predicted NMR data correctly reproduce the available experimental data for unsubstituted N-alkylcarbazoles.
AB - Structures of selected 3,6-dihalogeno-N-alkyl carbazole derivatives were calculated at the B3LYP/6-311++G(3df,2pd) level of theory and their 13C NMR isotropic nuclear shieldings were predicted using density functional theory (DFT). The model compounds contained 9H-, N-methyl and N-ethyl derivatives. The relativistic effect of Br and I atoms on nuclear shieldings was modeled using the spin-orbit ZORA method. Significant heavy atom shielding effects for the carbon atom directly bonded with bromine and iodine were observed (~ -10 and ~ -30 ppm while the other carbon shifts were practically unaffected). The decreasing electronegativity of the halogen substituent (F, Cl, Br and I) was reflected in both nonrelativistic and relativistic NMR results as decreased values of chemical shifts of carbon atoms attached to halogen (C3 and C6) leading to a strong sensitivity to halogen atom type at 3 and 6 positions of the carbazole ring. The predicted NMR data correctly reproduce the available experimental data for unsubstituted N-alkylcarbazoles.
KW - Faculty of Science
KW - NMR
KW - carbazole
KW - chemical shift
KW - relativistic effects
KW - quantum chemistry
KW - computational chemistry
KW - density functional theory
KW - DFT
U2 - 10.1002/mrc.3992
DO - 10.1002/mrc.3992
M3 - Journal article
C2 - 23922027
VL - 51
SP - 630
EP - 635
JO - Magnetic Resonance in Chemistry
JF - Magnetic Resonance in Chemistry
SN - 0749-1581
IS - 10
ER -
ID: 47286345