A new spirofluorene-based nonplanar PBI-dyad and its utilization in the film-based photo-production of singlet oxygen

Traditional photosensitizers are predominantly based on various types of polypyrrole macrocycles, which are generally used in homogeneous and/or suspension states. In the present study, a new non-polypyrrole-based photosensitizer(LW-PBI) was developed via the introduction of a nonplanar spirofluorene into a derivative of perylene bisimides(PBI) containing two longalkyl chains. Photophysical studies demonstrated that the compound shows good solubility in common organic solvents, great photochemical stability, and high absorption efficiency in the visible light region. Due to containing of two energetically matchable, independent fluorescent units, the compound as prepared displays strong tendency to form non-fluorescent chargeseparated states under light irradiation in polar solvents. Based on the merits, LW-PBI was examined for its catalytic property in the photo-production of singlet oxygen in film state. Luckily, the compound is an effective photosensitizer in the generation of the active oxygen species as verified by its unique reaction with uric acid(UA). Further studies revealed that the effective photoproduction of singlet oxygen can be also realized via the utilization of a tiny and low-price LED lamp as a light source and as a film support. Detailed studies on the application of the conceptual device as a medical instrument for photodynamic therapy(PDT) are in progress.

Toward Eco-friendly Green Organic Semiconductors： Recent Advances in Spiro[fluorene-9,9＇-xanthene] （SFX）-Based Optoelectronic Materials and Devices

Green organic semiconductors （GOS） have the four-element features, including biomass as stuffs, synthesis with the pot, atom and step economic （PASE） route, eco-friendly fabrication processes in aqueous phase, and recy- clable devices, capturing the trend of organic electronics in the future. Herein, we reviewed the efforts that have been made on GOS by our group. We first made a brief introduction of organic （opto）electronics, followed by the design strategies of GOSs based on spirofluorenes. Concretely, we described the discovery of one-pot protocol to spirofluorenres and a pot-atom-step economic （PASE） platform of spiro[fluorene-9,9＇-xanthene] （SFX） for the mo- lecular design of organic semiconductors, as well as a state-of-the-art nanocrystalline films with eco-friendly pro- cedures. Then, we highlighted the progress on SFX-based organic semiconductors in the organic light-emitting di- ode （OLED） field. Finally, we conducted a summary on SFXs in OLED and an outlook on green semiconductors starting from biomass, via one-pot to spirofluorenes, to water-phase devices.

One-Pot Synthesis of Spiro[fluorene-9,9'-xanthene]Derivatives

As a novel class of spirofluorenes,spirobifluorene(SBF)and spiro[fluo-rene-9,9'-xanthene]derivatives(SFXs)have orthogonal geometric config-uration,spiro-conjugation effect,and rigid steric hindrance,which can be widely used in the fields of synthetic chemistry,materials chemistry and supramolecular chemistry.Due to their facile one-pot synthetic route,and to the variety of molecular designs,SFXs are expected to become new spiro functional materials that replace SBF.In this review,we present the history,development and expansion of SFXs synthesis in one-pot methods,and the advantages and limitations of one-pot synthesis are also dis-cussed.