Article révisé par les pairs
Résumé : The sensitivity to solvent effects (α′) of the integrated intensity ACN of the CN stretching band in polycyclic aromatic nitriles is characterised by the slope of the straight line obtained by plotting, solvent by solvent, ΔACN 1 2 = [ACN 1 2(C2Cl4) - ACN 1 2 (solvent)] vs. ΔACN 1 2- values obtained for 2-cyano-naphthalene taken as the molecule of reference. It is shown that there exists a good linear relation between the observed α′-values and the known experimental dipole-moments. Similar plots characteristic of the solvents used were also obtained. The slope of these lines (α) is a measure of the ability of the solvent to induce intensity changes in the νCN vibration. A fair parallelism exists between the α-values and Reichardt's [20] ET-values; specific solvent-solute interactions must however be taken into account. The scope and limitations of these relations are discussed critically. © 1968.