TY - JOUR
T1 - Experimental and theoretical study of the ethoxy group conformational effect on 13C chemical shifts in Ortho-substituted phenetols
AU - Kowalewski, DG
AU - Kowalewski, VJ
AU - Botek, Edith
AU - Contreras, RH
AU - Facelli, JC
PY - 1997
Y1 - 1997
N2 - The 13C chemical shifts of nine 2-X-substituted phenetol derivatives were measured together with the 13C chemical shifts of the corresponding X-monosubstituted benzenes. Using an additivity scheme, the ethoxy cis- and trans-ortho-SCSs (substituent chemical shifts) at C-6 and C-2, respectively, were determined to be shielding effects of 16.5 and 10.9 ppm, respectively, which are close to those determined previously in anisole derivatives. Optimized geometries at the Hartree–Fock level employing a D95** basis set for three different phenetol conformers were obtained and the corresponding chemical shifts of all 13C nuclei were calculated using the same basis set and the CHF-GIAO approach. Results are discussed in terms of different interactions defining different conformations, particularly that between a polar bond and a proximate highly polarizable one.
AB - The 13C chemical shifts of nine 2-X-substituted phenetol derivatives were measured together with the 13C chemical shifts of the corresponding X-monosubstituted benzenes. Using an additivity scheme, the ethoxy cis- and trans-ortho-SCSs (substituent chemical shifts) at C-6 and C-2, respectively, were determined to be shielding effects of 16.5 and 10.9 ppm, respectively, which are close to those determined previously in anisole derivatives. Optimized geometries at the Hartree–Fock level employing a D95** basis set for three different phenetol conformers were obtained and the corresponding chemical shifts of all 13C nuclei were calculated using the same basis set and the CHF-GIAO approach. Results are discussed in terms of different interactions defining different conformations, particularly that between a polar bond and a proximate highly polarizable one.
U2 - 10.1002/(SICI)1097-458X(199706)35:6<351::AID-OMR6>3.0.CO;2-T
DO - 10.1002/(SICI)1097-458X(199706)35:6<351::AID-OMR6>3.0.CO;2-T
M3 - Article
VL - 35
SP - 351
EP - 356
JO - Magnetic Resonance in Chemistry
JF - Magnetic Resonance in Chemistry
IS - 6
ER -