Nuclear magnetic resonance studies. IV. The analysis of the spectra of two thiophene derivatives

Abstract

Complete analyses of the nuclear magnetic resonance spectra of 5-(but-3-en-1-yny1)-2,2'-bithienyl (I) and α-terthienyl (II) were carried out. The chemical shifts and coupling constants obtained for the ABC systems present are compared with those determined by the approximation method of Hoffman and Gronowitz. This method affords remarkably good chemical shift values for even very strongly coupled systems.