Journal of the Chemical Society Perkin Transactions 2 · 1981 · 29 citations · 0 references
Natural SciencesChemistryPhysicsOrganic ChemistryPhysical ChemistrySpectroscopyAb Initio MethodsConformational AnalysisElectronic StructureMolecular Orbital TheoryMolecular SymmetryPhotoelectron SpectroscopyCis ApproachConformational Electronic EffectsConformational EnergeticsConformational Energy TransitionsDipole Moment DeterminationMesomeric EffectsMolecular Conformation PredictionPyrrole Chemistry
The electric dipole moments and HeI photoelectron spectra (p.e.s.) of 2-(2-furyl)pyrrole and 2-(2-thienyl)pyrrole have been measured and analysed. Dipole moment data, in conjunction with theoretical calculations of conformational energy at the ab initio STO–3G level, show that the most likely conformations for these molecules are the fully planar cis and trans, the former being more favourable. This conformational conclusion is supported by the p.e.s. evidence of strong mesomeric interaction between the two rings in both the molecules. Assignments of the p.e.s. bands have been made upon PMO analysis by comparison with those of the parent monocyclic compounds.