SPECTROSCOPIC STUDIES .18. COMPARATIVE H-1 AND C-13 NMR-STUDY OF ISOELECTRONIC O, S, SE AND TE ARYL ESTERS OF AROMATIC CARBOXYLIC-ACIDS

The 13C resonances of the sp2 hybridized carbon atoms of the isoelectronic substituted O-, S-, Se-, and Te-aryl esters of benzenecarboxylic acids (I-IV) and of the benzenedicarboxylic acid (IX) as well as of the diaryl dichalkogenides V-VII are assigned. The same is done for the aromatic 1H NMR peaks of compounds III, IV, VI and IX. The influence of the chalkogen atoms on the positions of these NMR signals in all isoelectronic series of compounds is discussed. Furthermore parallels in the effects of the four chalkogenes O, S, Se, and Te in the compounds I-VII and IX as well as the four halogens F, Cl, Br, and I in the 4-halotoluenes VIII on the 1H and 13C resonances of the aryl rings directly attached to these elements are described and explained. © 1979.