TY - JOUR
A1 - Kolocouris, Antonios
A1 - Koch, Andreas
A1 - Kleinpeter, Erich
A1 - Stylianakis, Ioannis
T1 - 2-Substituted and 2,2-disubstituted adamantane derivatives as models for studying substituent chemical shifts and C-H-ax center dot center dot center dot Y-ax cyclohexane contacts-results from experimental and theoretical NMR spectroscopic chemical shifts and DFT structures
T2 - Tetrahedron
N2 - The complete H-1 and C-13 NMR chemical shifts assignment for various 2-substituted and 2,2-disubstituted adamantane derivatives 1-38 in CDCl3 solution was realized on the basis of NMR experiments combined with chemical structure information and DFT-GIAO (B3LYP/6-31+G(d,p)-GIAO) calculations of chemical shifts in solution. Substituent-induced C-13 NMR chemical shifts (SCS) are discussed. C-H-ax center dot center dot center dot Y-ax contacts are a textbook prototype of steric hindrance in organic chemistry. The nature of these contacts will be further investigated in this work on basis of new adamantane derivatives, which are substituted at C-2 to provide models for 1,4-C-H-ax center dot center dot center dot Y-ax and 1,5-C-H-ax center dot center dot center dot Y-ax contacts. The B3LYP/6-31+G(d,p) calculations predicted the presence of NBO hyperconjugative attractive interactions between C-H-ax and Y-ax groups along C-H-ax center dot center dot center dot Y-ax contacts. The H-1 NMR signal separation, Delta delta(gamma-CH2), reflects the strength of the H-bonded C-H-ax center dot center dot center dot Y-ax contact. (C) 2015 Elsevier Ltd. All rights reserved.
KW - 2-Substituted adamantane derivatives
KW - 2,2-Disubstituted adamantane derivatives
KW - H-1 NMR
KW - C-13 NMR
KW - B3LYP/6-31+G(d,p) calculations
KW - GIAO calculations
KW - Substituent chemical shifts
Y1 - 2015
UR - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/38995
SN - 0040-4020 (print)
VL - 71
IS - 16
SP - 2463
EP - 2481
PB - Elsevier
CY - Oxford
ER -