The transformation of trichalcogenasumanene buckybowls into donor–acceptor-type [5-6-7] fused polyheterocycles is disclosed. The strategy involves a highly efficient ring-opening of the flanking benzene upon oxidation at room temperature, and facile ring closure by functional-group transformation. Crystallographic studies indicate that the resulting [5-6-7] fused polyheterocycles possess a planar conformation owing to the release of ring strain by expansion of one of the six-membered flanking rings to the seven-membered one. Additionally, the [5-6-7] fused polyheterocycles bear electron-withdrawing groups, which reduce the HOMO–LUMO energy gap, and display broad absorption bands extending to λ=590 nm. Consequently, these compounds show strong red emission with fluorescence quantum yields of up to 38 %.

The transformation of trichalcogenasumanene buckybowls into donor–acceptor-type [5-6-7] fused polyheterocycles is disclosed. The strategy involves a highly efficient ring-opening of the flanking benzene upon oxidation at room temperature, and facile ring closure by functional-group transformation. Crystallographic studies indicate that the resulting [5-6-7] fused polyheterocycles possess a planar conformation owing to the release of ring strain by expansion of one of the six-membered flanking rings to the seven-membered one. Additionally, the [5-6-7] fused polyheterocycles bear electron-withdrawing groups, which reduce the HOMO–LUMO energy gap, and display broad absorption bands extending to λ=590 nm. Consequently, these compounds show strong red emission with fluorescence quantum yields of up to 38 %.

Tetrathiafulvalene derivatives (TTF1–TTF9) bearing fluorinated phenyl groups attached through the sulfur bridges have been synthesized by employing a copper-mediated C–S coupling reaction of C₆H_5−xF_xI (x=1, 2, 5) and a zinc-thiolate complex, (TBA)₂[Zn(DMIT)₂] (TBA=tetrabutyl ammonium, DMIT=1,3-dithiole-2-thione-4,5-dithiolate), as the key step. Particularly, the selective synthesis of C₆F₅-substituted (TTF8) and C₆F₄-fused (TTF9) TTFs from C₆F₅I is disclosed. The physicochemical properties and crystal structures of these TTFs are fully investigated by UV/Vis absorption spectra, cyclic voltammetry, molecular orbital calculation, and single-crystal X-ray diffraction. The exchange of hydrogen versus fluorine on the peripheral phenyl groups show a notable influence on both the electronic and crystallographic natures of the resulting TTFs: 1) lowering both the HOMO and the LUMO energy levels, 2) modulating the electrochemical properties by regioselective and/or the degree of fluorination, 3) enhancing the driving forces of stacking by multiple fluorine interactions (F⋅⋅⋅S, CF⋅⋅⋅π/π_F, CF⋅⋅⋅FC, and CF⋅⋅⋅H). This work indicates that the decoration with fluorinated phenyls holds promise to produce functional TTFs with novel electronic and aggregation features.

Trichalcogenasumanenes were synthesized on a multigram scale through a two-step approach that takes advantage of non-pyrolytic cyclization and solventless ring contraction. Solid-state structure and photophysical investigations demonstrate that these compounds are promising candidates for electronic materials.

Trichalcogenasumanenes were synthesized on a multigram scale through a two-step approach that takes advantage of non-pyrolytic cyclization and solventless ring contraction. Solid-state structure and photophysical investigations demonstrate that these compounds are promising candidates for electronic materials.

Three dixanthones (1–3) and an unprecedented C_3h-symmetric trixanthone (4) were synthesized through a three-step approach in overall yields above 63 %. These compounds possessed a planar π-conjugated system and formed tight face-to-face columnar stacks, as confirmed by single-crystal structural analysis. In comparison with xanthone, the fluorescence emissions of compounds 1–4 showed significant red-shifts, with improved quantum yields. Moreover, the fluorescence emissions of compounds 1–4 could be modulated in a strongly acidic environment without decomposition, which led to a further red-shift of the emissions, as well as enhancement of the emission intensities. These compounds have potential applications as optoelectronic materials and/or chemosensors.

A library of tetrathiafulvalene (TTF) derivatives (TTF-1–TTF-47) bearing aryl groups attached through sulfur bridges has been created. The peripheral aryl groups exert a significant influence on both the electronic and crystallographic properties of the resulting TTFs. These TTFs display broad absorption bands at 400–500 nm caused by intramolecular charge-transfer transitions between the aryl groups and central TTF core, and their first redox potentials increase with increasing electron-withdrawing ability of the aryl groups. In their crystal structures (22 examples), the central TTF cores adopt various conformations, including chair, half-chair, boat, and planar conformations. Moreover, the peripheral aryl groups exhibit multiple alignment modes with respect to the central TTF core, caused by their rotation about the two CS bonds of the sulfur bridges. The packing motifs of these TTFs depend on both the nature of the aryl groups and their spatial alignment modes. Driven by intermolecular van der Waals forces and π–π interactions between the aryl groups and between the aryl groups and the TTF core, these TTFs adopt various packing structures. As a typical example, TTF-14, an achiral molecule, adopts a helical chain stack through intermolecular atomic close contacts. Moreover, the molecular geometries and packing motifs of these TTFs are sensitive to environmental variation, as exemplified by TTF-28, which adopts three distinct crystal modifications with diverse molecular geometries and stacking modes under different crystallization conditions. This work indicates that these TTFs are potential candidates as electronic materials, as well as functional building blocks for supramolecular assembly.