UV-VISIBLE LUMINESCENCE ANALYSIS OF PARA- NITROANALINE

The modification spectra of p-nitroaniline were evidenced by dipolar i nteraction effects and hydrogen bond complexes. This complexation was obtained either with the water traces present as impurity in aprotic s olvents at low temperature, or by direct associations with OH groups i n protic solvent's. It conferred on the molecule a twisted conformatio n in the ground state due to the rotation of the NH2 group around the C-NH2 bond. This important result agrees with an anomalous result obta ined in emission data which shows dependence of fluorescence/phosphore scence intensity ratio (I-f/I-pn on excitation energy. It is explained by mixed rotamers that exhibit this molecule in the ground state. The calculated geometry characteristics for this molecule show the abilit y of some theoretical methods to reproduce accurately the experimental data.