Novel, stimulus-responsive supramolecular structures in the form of fibers, gels, and spheres, derived from an azobenzene-containing benzenetricarboxamide derivative, are described. Self-assembly of tris(4-((E)-phenyldiazenyl)phenyl)benzene-1,3,5-tricarboxamide (Azo-1) in aqueous organic solvent systems results in solvent dependent generation of microfibers (aq DMSO), gels (aq DMF), and hollow spheres (aq THF). The results of a single crystal X-ray diffraction analysis of Azo-1 (crystallized from a mixture of DMSO and H2O) reveal that it possesses supramolecular columnar packing along the b axis. Data obtained from FTIR analysis and density functional theory (DFT) calculation suggest that multiple hydrogen bonding modes exist in the Azo-1 fibers. UV irradiation of the microfibers, formed in aq DMSO, causes complete melting while regeneration of new fibers occurs upon visible light irradiation. In addition to this photoinduced and reversible phase transition, the Azo-1 supramolecules display a reversible, fiber-to-sphere morphological transition upon exposure to pure DMSO or aq THF. The role played by amide hydrogen bonds in the morphological changes occurring in Azo-1 is demonstrated by the behavior of the analogous, ester-containing tris(4-((E)-phenyldiazenyl)phenyl)benzene-1,3,5-tricarboxylate (Azo-2) and by the hydrogen abstraction in the presence of fluoride anions.

The therapeutic interventions or prophylaxis discussed in this review seems to offer promising solutions to tackle SARS. Rather than being complacent about the results, we should envisage how to transform them into drug candidates that may be useful in combating SARS and related viral infections in the future.

Photoredox-catalyzed vicinal chlorotrifluoromethylation of alkene is described. In the presence of Ru(Phen)3Cl2, CF3SO2Cl was used as a source for the CF3 radical and chloride ion under visible light irradiation. Various terminal and internal alkenes were transformed to their vicinal chlorotrifluoromethylated derivatives. Biologically active compounds were applied under the condition to obtain desired products, suggesting that the method could be feasible for late-stage modification in drug discovery.

A combinatorial approach for the colorimetric differentiation of organic solvents is developed. A polydiacetylene (PDA)‐embedded electrospun fiber mat, prepared with aminobutyric acid‐derived diacetylene monomer PCDA‐ABA 1, displays colorimetric stability when exposed to common organic solvents. In contrast, a fiber mat prepared with the aniline‐derived diacetylene PCDA‐AN 2 undergoes a solvent‐sensitive color transition. Arrays of PDA‐embedded microfibers are constructed by electrospinning poly(ethylene oxide) solutions containing various ratios of two diacetylene monomers. Unique color patterns are developed when the conjugated polymer‐embedded electrospun fiber arrays are exposed to common organic solvents in a manner which enables direct colorimetric differentiation of the tested solvents.