We report the synthesis and characterization of two hexapole [7]helicenes (H7Hs). Single crystal X-ray diffraction unambiguously confirms the molecular structure. H7H absorbs light, with distinct Cotton effect, from ultraviolet to the near-infrared (λ = 618 nm). Cyclic voltammetry reveals nine reversible redox states, consecutively from -2 to +6. These chiroptical and electronic properties of H7H are inaccessible from helicene's small homologues.

A photocatalytic system containing a perylene bisimide (PBI) dye as a photosensitizer anchored to titanium dioxide (TiO2) nanoparticles through carboxyl groups was constructed. Under solar‐light irradiation in the presence of sacrificial triethanolamine (TEOA) in neutral and basic conditions (pH 8.5), a reaction cascade is initiated in which the PBI molecule first absorbs green light, giving the formation of a stable radical anion (PBI.−), which in a second step absorbs near‐infrared light, forming a stable PBI dianion (PBI2−). Finally, the dianion absorbs red light and injects an electron into the TiO2 nanoparticle that is coated with platinum co‐catalyst for hydrogen evolution. The hydrogen evolution rates (HERs) are as high as 1216 and 1022 μmol h−1 g−1 with simulated sunlight irradiation in neutral and basic conditions, respectively.

Photoinduced charge separation (CS) kinetics are observed to be strongly related to the molecular conformation of the monomeric units in perylene diimide (PDI) dyads, which contain identical or different PDI units linked through N−N covalent bonding. Ultrafast photoinduced intramolecular CS was observed in dichloromethane at room temperature for the dyads containing twisted tetra(phenoxy)-substituted PDI units (1−1 and 1−2), while the dyad containing two identical planar bay-area unsubstituted PDI units (2−2) maintains high fluorescence at the same conditions, although the freeenergy difference (ΔG CS ) for CS is all negative for these dyads. The interchromophore rotation at excited states between the adjacent chromophores in the dyads is a key factor for CS.

Conjugation breaking by “node” structures in donor–node–acceptor (D–n–A)-type molecules conceptually enables facile tuning of their oxidation and reduction behaviors through modification of the donor (D) unit and the acceptor (A) unit independently. Herein, we demonstrate the successful synthesis of a series of D–n–A-type cross-linked polymers, termed poly-4T-PDI, poly-2T3-PDI, and poly-4T3-PDI, by an in situ electrochemical polymerization reaction on the surface of electrodes and their versatile redox properties. These polymers contain oligo-thiophene structures connected with tetrachloronated perylene diimide (PDI) units through the “N node”. The investigation of the redox behaviors of these three polymers clearly indicates that there are two reversible redox waves corresponding to the oxidation–reduction couples of PDI/PDI– and PDI–/PDI2–; however, the redox signal relating to the oligo-thiophene structures completely relies on the number and connection mode of thiophene units. Especially, poly-2T3-PDI possesses a balanced ambipolar characteristic showing approximately equivalent gravimetric capacitances of 299 F g–1 for the n-doping process and 264 F g–1 for the p-doping process, which facilitate the application of such ambipolar polymers as both cathode and anode materials in pseudocapacitors. In addition, electrochemical impedance spectroscopy indicates easy ion diffusion and fast electron transfer in the film of poly-2T3-PDI, which is attributed to the fine porous structure and the conjugated backbone of polythiophene. The current research clearly demonstrates a facile strategy to achieve balanced ambipolar polymers through conjugation breaking by the “node” structure between the electron donor and acceptor units.

A homoditopic molecular host, janusarene, is presented that has two back-to-back compactly arranged nanocavities for guest complexation. The unique two-face structural feature of janusarene allows it to bind and align various guest compounds concurrently, which include spherical pristine fullerene C and planar polycyclic aromatic hydrocarbons (PAHs), such as pyrene, perylene, and 9,10-dimethylanthracene. The host-guest interactions were characterized by single-crystal X-ray diffraction. A pairwise encapsulation of the PAH guests by janusarene enables PAH dimers to be obtained that deliver spectroscopic properties distinct from those of PAHs dissolved in solution, or in the bulk state. A monotopic control host was also synthesized and used to characterize the host-guest complexing behavior in solution.