Organic charge-transfer complexes for the selective accommodation of aromatic isomers using anthracene derivatives and TCNQ

Abstract

Four new organic charge-transfer complexes (Ct1, Ct2, Ct3 and Ct4) were engineered via anthracene derivatives, namely, acetyl-3-phenyl-5-(9-anthryl)-2-pyrazoline/1-acetyl-3-naphthyl-5-(9-anthryl)-2-pyrazoline as donors and tetracyanoquinodimethane as the acceptor by a solution crystallization method. The resulting encapsulated charge-transfer complexes (Ct2–Ct4) characterized by single crystal X-ray diffraction (SCXRD) analysis showed the formation of channels in the supramolecular architecture through various non-covalent interactions. Interestingly, Ct1 demonstrated remarkable selectivity towards p-xylene over the other xylene isomers to form the Ct1·p-xylene inclusion complex. Ct2 and Ct3 contain p-xylene, whereas Ct4 features p-chlorotoulene. Moreover, the closely matched powder X-ray diffraction (PXRD) profile revealed that Ct2 and Ct1·p-xylene are isomorphic.