Zongxia Guo

The effective chiral resolution of amino acid racemates has important significance in fields such as medicine and pharmaceuticals. By using phenylalanine as additive, the chiral resolution of aspartic acid racemate was investigated through crystallization method. It reveals that the enantiomeric excess of the crystalline product is affected by the seeding temperature, crystallization temperature, crystallization time, seed dosage, phenylalanine dosage, and the relative supersaturation. Under optimized condition, the average enantiomeric excess could reach 85% after a single crystallization in water. The excess enantiomer of the crystalline product is determined by the configuration of phenylalanine. The enantiomeric excess and the excess enantiomer were confirmed by chiral high performance liquid chromatography. The powder X‐ray diffraction and Fourier transform infrared spectral results show that conglomerate was formed in the crystalline product. Seed and additive both play great role in the chiral resolution. The findings could give inspirations for efficient resolution of aspartic acid racemate into enantiopure compounds.

Radioactive iodine is a harmful pollutant in gaseous nuclear waste that can cause irreversible damage to both humans and the environment. The organic macrocyclic molecules OMM-1 and OMM-2 were synthesized through a Schiff-base reaction and could be handled easily and efficiently. Nitrogen adsorption experiments confirmed the porous structure of the OMM powders. The OMM-1 powder exhibited excellent iodine vapor capture properties, with a maximum adsorption capacity of up to 421.9 wt%. This exceptional iodine vapor capture capability likely arose from the porous structure; furthermore, charge transfer complexes might form between iodine and the aromatic systems containing imine bonds. More importantly, it was found that the iodine adsorption capacity remained as high as 99.5% after repeating the adsorption–desorption experiments 5 times. This research has potential applications and might provide alternative strategies for the treatment of radioactive iodine vapor in nuclear waste gas.

In this work, a one‐step method synthesis of lactide is reported instead of the traditional two‐step method. The selection of a suitable acid catalyst polyphosphoric acid and optimization of reaction conditions result in a yield of 97%. Moreover, this new one‐step strategy eliminates the need for metal catalysts and does not require high‐temperature conditions, thereby avoiding the issue of racemization. The simple one‐step strategy offers a combination of efficiency, sustainability, and product quality improvements, making it a modern, practical approach to lactide synthesis.

One of the challenging issues that hinders the application of single-walled carbon nanotubes (SWCNTs) is the poor solubility and the inevitable formation of bundles. Efforts still need to be made towards solving the problem. Herein, we report a non-covalent strategy to disperse aggregated SWCNTs by aromatic cyclic Schiff bases assisted by ultrasonic techniques. The aromatic cyclic Schiff base (OMM) was synthesized via Schiff base reactions, and the molecular structure was determined by ATR-FT-IR, solid-state ¹³C-NMR, and HRMS. Although the yielded product showed poor solubility in aqueous solution and organic solvents, it could interact with and disperse the aggregated SWCNTs in dimethyl formamide (DMF) under the condition of ultrasound. UV-vis-NIR, FL, Raman spectra, AFM, and TEM, along with computer simulations, provide evidence for the interactions between OMM molecules and SWCNTs and the dispersion thereof. The semiconductive (7,5), (8,6), (12,1), and (9,7)-SWCNTs expressed a preference for dissolution. The capability of dispersion is contributed by π-π, C-H·π, and lone pair (lp)·π interactions between OMM and SWCNTs based on the simulated results. The present non-covalent strategy could provide inspiration for preparing organic cyclic compounds as dispersants for SWCNTs and then facilitate their further utilization.

The self-assembly of a C₃-symmetric molecule benzene-1,3,5-tricarboxylate substituted with methyl cinnamate (BTECM) has been investigated by a reprecipitation method in H₂O and cetyltrimethylammonium bromide (CTAB) aqueous solution, respectively.

Terrylene diimide derivatives are pigments for dyes and optoelectric devices. A terrylene diimide derivative N,N'-di(1-undecyldodecyl)terrylene-3,4:11,12-tetracarboxdiimide (DUO-TDI) decorated with long branched alkyl chains on both imide nitrogen atoms was designed and synthesized. The supramolecular assembly behaviors of DUO-TDI in solution and at the liquid-solid interface were both investigated. The assembled nanostructures and photophysical properties of TDI in solution were explored by varying solvent polarity with spectral methods (UV-Vis, FL and FT-IR) and morphological characterization (AFM). Depending on the solution polarities, fibers, disk structures and wires could be observed and they showed diverse photophysical properties. In addition, the interfacial assembly of DUO-TDI was further investigated at the liquid-Highly Oriented Pyrolytic Graphite (HOPG) interface probed by scanning tunneling microscope (STM). Long range ordered monolayers composed of lamellar structures were obtained. The assembly mechanisms were studied for DUO-TDI both in solution and at the interface. Our investigation provides alternative strategy for designing and manipulation of supramolecular nanostructures and corresponding properties of TDI based materials.

The assembly of a peptide-tetrathiophene-peptide (PTP) conjugate has been investigated in mixed solvents, which has different polarities by changing the solvent proportions. It was found that PTP can form fibers in THF/hexane solutions with 40–80%v of hexane. The fibers were stable and did not change on time. On the other hand, PTP formed ordered structures in a mixed solution with the water content from 40 to 60%v. For the as-prepared solutions, two nanostructures vesicles and parallelogram sheets were obtained. The parallelogram sheets could transform into vesicles on time. The fibers showed supramolecular chirality, however, there was no Cotton effect for vesicles and parallelogram sheets. UV-vis, FL, XRD, FT-IR, and CD spectra together with SEM, AFM, TEM were used to characterize the nanostructures and properties of the assemblies. Molecular packing mechanism was proposed based on the experimental data.

Materials with circularly polarized luminescence (CPL) are currently attracting great interest in view of their potential applications. Here, we reported self-assembled organic nanotubes with switchable CPL performance. A photoacid, 8-hydroxy-1,3,6-pyrenetrisulfonate (HPTS), was co-assembled with an amino-terminated dialkyl glutamide (LG or DG) in mixed solvents of DMF and water. The complex of LG (DG)/HPTS self-assembled into nanotube structures in the tested range of mixed solvents and showed CPL emission. Different mixing ratios of DMF to water in the solvent triggered CPL switching between different wavelengths. It was revealed that the switching of CPL resulted from the different emissions of the protonated (ROH) and deprotonated (RO⁻) forms of HPTS, which could be regulated by the solvent polarity. Interestingly, the addition of an acid or base could also switch the fluorescence of LG (DG)/HPTS co-assemblies and the corresponding CPL, leading to an acidity-regulated CPL switch. Thus, through a simple co-assembly strategy, switchable CPL was realized in the self-assembled organic nanotubes via both solvent polarity and acidity.

Porous organic polymers (POPs) have been considered as prominent adsorbents for volatile iodine. So far, both crystalline and amorphous POPs have accomplished excellent iodine capture capability. Considering the difficulty and challenges in preparing perfect crystalline POPs, more explorations into developing versatile amorphous POPs are needed. Herein, amorphous POPs based on the Schiff‐base reaction were designed and synthesized for volatile iodine removal. Four amorphous POPs products named as NDB‐H, NDB‐S, ADB‐HS, and ADB‐S obtained under different solvothermal conditions were investigated in terms of their morphologies, porosity, and their iodine enrichment performance in detail. It is noteworthy that excellent efficiency for removing iodine vapor was acquired for NDB‐S (≈425 wt %), ADB‐HS (≈345 wt %), and ADB‐S (≈342 wt %). Remarkably, NDB‐H exhibited an iodine capture capacity up to ≈443 wt %. Excellent reusability was obtained as well. Amorphous NDB‐H has accomplished an extremely high iodine capture performance, illustrating the great chance to exploit versatile amorphous POPs for iodine enrichment and removal based on Schiff‐base chemistry.