Conformational and Optical Characteristics of Unidirectionally Twisted Binaphthyl-Bipyridyl Cyclic Dyads

Abstract

An axially chiral binaphthyl-bipyridyl cyclic dyad in which the two units are connected by short −CH₂O– linkers was synthesized. Experimental and theoretical analyses indicate that the (<i>R</i>)-binaphthyl unit in the dyad induces (<i>R</i>)-chirality in the bipyridyl unit, both in the solid state and in solution. It is shown that vibrational circular dichroism (VCD) is useful to determine the twisting pattern of 2,2′-bipyridyl compounds. The dyad shows crystallization-induced emission enhancement (CIEE)