Health & Environmental Research Online (HERO)


Print Feedback Export to File
8685536 
Journal Article 
The electronic spectra of N-heteroaromatic systems. Part I. The n→π transitions of monocyclic azines 
Mason, SF 
1959 
Yes 
Journal of the Chemical Society
ISSN: 0368-1769 
1240-1246 
English 
The positions and the intensities of the band in the visible and the ultra-violet spectra of monocyclic azines due to the promotion of an electron from a lone-pair nitrogen orbital to a re-orbital of the ring have been measured for the vapour phase for cyclohexane and aqueous solutions. The frequency of the band is determined primarily by the energy of the benzene-like lowest unoccupied π-orbital of the azine and by ground-state interaction between lone-pair orbitals on different-nitrogen atoms. The intensities of the n→π bands of the azines increase with the "s" character of the lone-pair nitrogen orbitals, but the frequencies of the bands are not greatly affected, owing to orbital-following in the transition.