Cyclized oligomer of tetracyanoquinodimethane-tetrathiafulvalene (TCNQ-TTF): a versatile macrocyclic molecule by DFT calculations

The combination of the electron donor and acceptor into a donor–acceptor system can transform the intermolecular charge transfer (CT) property into the intramolecular CT property, which is of great significance when exploring and expanding the application potential of conductive molecules. This work creatively incorporates tetracyanoquinodimethane (TCNQ, acceptor) and tetrathiafulvalene (TTF, donor) alternately into macrocyclic molecule, resulting in cyclopolymer of TCNQ-TTF (named C[n]QF, n = 4 − 7). The structures of C[n]QF are optimized by using density functional theory (DFT) at the M062X/6-311 g(d) level. DFT calculation results show that C[n]QFs have excellent intramolecular CT capability and multi-redox activity. Their absorption spectra are in the visible light range leading to good light responding properties. The double-walled assembly and host–guest inclusion performance of C[n]QF indicate their remarkable ability as building blocks for supramolecular systems. Based on DFT calculations, C[n]QF are expected to have potential applications in organic photoelectric, electrochemical sensing, and supramolecular materials.