13C NMR and Force Field Investigations of Hydrindane Conformations

Article abstract of DOI:10.1002/mrc.1270180109

13C NMR shifts of trans- and cis-annelated bicyclo<4.3.0>nonanes with substituents R in position 8 (R = H, OH, Cl, Br) and 1-hydroxy derivatives were analysed on the basis of force field calculated torsional angles using Allinger's MM1 program.Schielding increments for the 6 membered ring agree with corresponding cyclohexane values within +/-0.8 ppm maximal deviation. 13C NMR line shape analysis with cis-hydrindane between 148 and 180 K yielded ΔH* = 37.0 +/- 0.4 kJ mol^-1 and ΔS* = 28 J mol^-1 K^-1 for the topomerization.The force field calculated reaction profile showed ΔH* = 37 kJ mol^-1, in close agreement.