NUCLEAR-SPIN RELAXATION STUDY OF HYDROGEN-BONDING IN SOLUTIONS OF QUINUCLIDINE

Artikel i vetenskaplig tidskrift, 1984

The intermolecular hydrogen bonds formed by quinuclidine together with different solvents (benzene, chloroform, methanol, trifluoroacetic acid) are studied by using NMR relaxation measurements. The carbon-1 3 and nitrogen-I4 relaxation rates are determined and Woessner's model for dipole relaxation in a symmetric rotor is applied. The different values for the ratio between the rotational diffusion constants RII and R, in different solvents and at different temperatures are discussed in terms of molecular reorientation anisotropy due to hydrogen bonds formed by quinuclidine and the solvent. From the nitrogen-14 relaxation rates the quadrupole coupling constants (QCC) are evaluated and compared with the results of quantum-chemical calculations of electric field gradients performed on model systems.