Synthesis and Photophysical Properties of Chiral Diaminodicyanoquinodimethane: Formation Mechanism and Chiroptical Properties

Chirality is fundamental to biological systems and the pharmaceutical industry, yet efficient methods for determining the absolute configuration of chiral compounds remain a challenge. This study reports the synthesis and characterization of chiral diaminodicyanoquinodimethane (DADQ) compounds derived from tetracyanoquinodimethane (TCNQ) and primary amines. Using a combination of NMR, UV-Vis, circular dichroism (CD) spectroscopy, and EPR, we elucidated the formation mechanism of these compounds and explored their optical properties. Furthermore, CD spectra showed a pattern that correlates with their configurations: DADQs with R configuration showed negative CD signals in methanol and DMSO, whereas DADQs with S configuration showed positive CD signals. The DADQs with aromatic side chains reversed their CD signals in relatively nonpolar solvents. These findings indicate that chirality can be effectively transferred from primary amines to DADQ, offering a potential method for determining the absolute configurations of primary amines. The results highlight the promise of chiral DADQ compounds in chiroptical applications and their utility in elucidating the chirality of biologically relevant molecules.