Tetrakis(tetrathiafulvalene–tetrathiacrown ether)porphyrazine Triads: Synthesis, Photophysical, and Electrochemical Properties

Abstract

A series of tetrakis(tetrathiafulvalene-tetrathiacrown ether)porphyrazine triads with long and flexible aliphatic side-chains at the periphery have been synthesized and characterized. Electrochemical investigations show two reversible four-electron oxidation waves, one reversible one-electron oxidation wave and two irreversible one-electron reduction waves, which indicates that these triads are good π-electron donors. Selected triad 4a reacted with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F₄TCNQ) to form a charge-transfer complex, which exhibits absorption bands at around 760 and 860 nm. Selected triads 4a and 5a bind silver(I) and mercury(II) ions. In the case of triad 4a, the addition of silver(I) ions led to dimerization of the triad, which fragmented to form monomeric 4:1 host–guest complexes when more than 2 equiv. of the metal ions were added. X-ray scattering at room temperature showed that triad 5c is a highly ordered oblique columnar structure in the bulk state. The crystal structures of the precursors 3b,c were also determined by X-ray diffraction analysis.