Synthesis of a novel tweezers-type host aiming at chiral discrimination by circular dichroism spectroscopy

Abstract

In order to develop a methodology for chiral discrimination by utilizing complexation-induced circular dichroism (ICD) in host–guest systems, the novel tweezers-type host 1 was synthesized. From UV-VIS and fluorescence emission studies, it was confirmed that the host 1 formed a 1∶1 complex with optically active N,N′-dimethyl-trans-1,2-diaminocyclohexane 16, and the CD spectrum was induced as the concentration of the complex increased. The sign of the Cotton effect induced by (S,S)-16 was opposite to that induced by (R,R)-16, indicating that enantioselective formation of the atropisomer of 1 upon complexation leads to determination of the chirality of the guest by CD. On the other hand, the ICD of 1 upon complexation with the chiral monoamine 17 implied that the axial chirality of 1 was not induced until the host complexed two molecules of 17.