A first porphyrin liquid crystal with strong fluorescence in both solution and aggregated states based on the AIE-FRET effect

Biomedical Application of Porphyrin-Based Amphiphiles and Their Self-Assembled Nanomaterials

Porphyrins have been vastly explored and applied in many cutting-edge fields with plenty of encouraging achievements because of their excellent properties. As important derivatives of porphyrins, porphyrin-based amphiphiles (PBAs) not only maintain the advanced properties of porphyrins (catalysis, imaging, and energy transfer) but also possess self-assembly and encapsulation capability in aqueous solution. Accordingly, PBAs and their self-assembles have had important roles in diagnosing and treating tumors and inflammation lesions in vivo, but not limited to these. In this article, we introduce the research progress of PBAs, including their constitution, structure design strategies, and performances in tumor and inflammation lesion diagnosis and treatments. On that basis, the defects of synthesized PBAs during their application and the possible effective strategies to overcome the limitations are also proposed. Finally, perspectives on PBAs exploration are updated based on our knowledge. We hope this review will bring researchers from various domains insights about PBAs.

Non-isothermal cold crystallization of liquid crystalline porphyrins

A series of liquid crystalline porphyrins was synthesized, purified, and characterized. Differential scanning calorimetry (DSC) and hot-stage polarized optical microscopy (HS-POM) revealed that the porphyrins in the series with shorter alkyl arm lengths exhibit kinetic cold crystallization, wherein the molecules spontaneously organize into large, disc-like structures that remain stable upon cooling. Using DSC, the kinetic and thermodynamic parameters related to these materials were determined. Analysis of non-isothermal crystallization revealed the presence of multiple nucleation and growth processes related to cold crystallization.

An Artificial Light-Harvesting System with Controllable Efficiency Enabled by an Annulene-Based Anisotropic Fluid

The development of controllable artificial light-harvesting systems based on liquid crystal (LC) materials, i.e., anisotropic fluids, remains a challenge. Herein, an annulene-based discotic LC compound 6 with a saddle-shaped cyclooctatetrathiophene core has been synthesized to construct a tunable light-harvesting platform. The LC material shows a typical aggregation-induced emission, which can act as a suitable light-harvesting donor. By loading Nile red (NiR) as an acceptor, an artificial light-harvesting system is achieved. Relying on the thermal-responsive self-assembling ability of 6 with variable molecular order, the efficiency of such 6-NiR system can be controlled by temperature. This light-harvesting system works sensitively at a high donor/acceptor ratio as 1000 : 1, and exhibits a high antenna effect (39.1) at a 100 : 1 donor/acceptor ratio. This thermochromic artificial light-harvesting LC system could find potential applications in smart devices employing soft materials.

A “turn-on” fluorescent sensor for cytosine in aqueous media based on diamino-bridged biphenyl acrylonitrile

A “turn-on” fluorescent sensor for cytosine in aqueous media was prepared.

Room-temperature AIE ionic liquid crystals based on diphenylacrylonitrile-imidazole salts

Although various AIE liquid crystals have been studied, AIE ionic liquid crystals (ILCs) are almost unknown to date. In this work, a series of novel AIE ILCs based on diphenylacrylonitrile-imidazole salts bridged by soft spacers with different anions were prepared in yields of 63-80%. The mesomorphic, photophysical and electrochemical properties were investigated systematically to elucidate the relationship between structures and properties. The results implied that they were the first room-temperature AIE ILCs with wide ranges of mesomorphic temperature, good fluorescence emission in both the solid state and mesophase, and stable electrochemical behaviour. The samples with one alkyl chain possessed the SmA₂ mesophase while the samples with two alkyl chains prefered the Col_h mesophase. The larger anions resulted in the bigger layer spacing length for the SmA₂ mesophase and smaller values of n_cell in each slice of Col_h mesophase. The fluorescence quantum yields in the mesophase maintained reasonable values (0.15-0.22), which decreased a little in comparison with that in solid films (0.18-0.26) due to the orderly molecular stacking in the mesophase. The cyclic voltammetry experiments confirmed that all of them possessed similar and stable electrochemical behaviour. This research not only presented the first room-temperature AIE ILCs with excellent mesomorphic, photophysical and electrochemical properties, but also elucidated the relationship between structures and properties to a certain degree, contributing to the further construction of novel AIE ILCs with excellent mesomorphic, photophysical and electrochemical properties.