
%0 Journal Article
%A Yokoyama, T 
%A Taft, RW 
%A Kamlet, MJ 
%T Resonance and solvent effects on absorption spectra of some 2- and 4-(&#8211;M)-substituted aniline derivatives
%J Australian Journal of Chemistry
%D 1983/04/01
%V 36
%N 4
%P 701-709
%K 
%R https://doi.org/10.1071/CH9830701
%U https://www.publish.csiro.au/paper/CH9830701 
%X The N-H protons of N-methyl-2-X-aniline derivatives remain intramolecularly hydrogen bonded in HBA (hydrogen bond acceptor) solvents where X = COOMe and NO2, but form intermolecular hydrogen bonds to the HBA solvents where X = CN. The order of response of vmax to solvent HBA basicity for the Cl &#8594; C2 bands of N-unsubstituted-2-(-M)-substituted aniline derivatives and the Cl &#8594; C4 bands of 4-(-M)-substituted aniline derivatives follows the orders of the hydrogen bond donor acidities of the amine protons, which are determined primarily by the mesomeric effects of the 2- and 4-substituents. The spectral data indicate that intramolecularly hydrogen bonded 2-(-M)-substituted aniline derivatives are near sp2 hybridized in non-HBA solvents and, unlike several 4-substitute anilines, do not undergo significant rehybridization in HBA solvents. Bath ochromic shifts resulting from hydrogen bonds by corresponding 2- and 4-substituted aniline derivatives to HBA solvents are of similar magnitudes. 
