N,N′-Disubstituted phenanthrene-9,10-diimines: synthesis and NMR spectroscopic study

Novel aryl-aryl, alkyl-alkyl, aryl-alkyl N,N′-disubstituted phenanthrene-9,10-diimines were synthesized by condensation of 9,10-phenanthrenequinone with primary amines. The novel two-stage method of synthesis of disubstituted phenanthrene-9,10-diimines with identical or different aryl and alkyl substituents at the nitrogen atom was established. The investigated compounds undergo slow Z-E/E-Z interconversion which was studied by NMR spectroscopy. Thermodynamic parameters of interconversion were obtained by variable temperature NMR spectroscopy.