Analyse kernmagnetischer Resonanzspektren vom Typ A2B2 mit Ergebnissen von para-disubstituierten Benzolen, Äthylengruppen und Pyrrol

Abstract

The analysis of A2B2 spectra, especially the assignment of lines is further treated. Explicit expressions for the A4 spectrum as a limiting case of an A2B2 spectrum have been calculated and are listed. The observation of multiple quantum transitions in an A2B2 system is reported. Spin coupling and shielding parameters are given for 30 para-disubstituted benzenes and some other compounds. For pyrrole an improved set of spin coupling parameters could be obtained, making use of the information from C13 satellites. Substituent effects for the meta spin coupling in paradisubstituted benzenes are derived. A correlation with the electronegativity of the substituent is demonstrated and some arguments for a theoretical treatment are discussed.