title: Dynamic 1H NMR study of the barrier to rotation about the C-N bond in primary carbamates and its solvent dependence.
abstract: The dynamic 1H NMR study of some primary carbamates in the solvents CDCl3 and CD3COCD3 between 183 and 298 K is reported. The free energies of activation, thus obtained (12.4 to 14.3 kcal mol-1), were attributed to the conformational isomerization about the N-C bond. These barriers to rotation show solvent dependence in contrast to the tertiary analogues and are lower in free energy by ca. 2-3 kcal mol-1.
authors.affiliation: Department of Chemistry, University of Sistan & Baluchestan, Zahedan, Iran. modaresi@hamoon.usb.ac.ir
authors.forename: Ali Reza
authors.initials: AR
authors.lastname: Modarresi-Alam
authors.forename: Parisa
authors.initials: P
authors.lastname: Najafi
authors.forename: Mohsen
authors.initials: M
authors.lastname: Rostamizadeh
authors.forename: Hossein
authors.initials: H
authors.lastname: Keykha
authors.forename: Hamid-Reza
authors.initials: HR
authors.lastname: Bijanzadeh
authors.forename: Erich
authors.initials: E
authors.lastname: Kleinpeter