Triphenylamine-based rhombimine macrocycles with solution interconvertable conformation

Abstract

Three imine macrocycles having rhomboidal shape were synthesized in good yields by [2+2] cyclocondensation reaction between equimolar quantities of (R,R)-1,2-diaminocyclohexane and 4,4′-bisformyl triphenylamine derivatives. The macrocycles structure was assigned by electrospray ionization mass spectrometry (ESI-MS), ¹H-NMR, and elemental analysis. UV, FTIR spectroscopy, and TG measurements were also used to characterize and prove the structure of these compounds. A conformational modification arising out of the rotation of triphenylamine group around the flexible cyclohexane-N bonds was observed in solution by ¹H-NMR and UV spectroscopy for all three macrocycles.