Zixuan Wang

We report the synthesis of hierarchical structured nanocrystals through an interfacial self-assembly driven microemulsion (μ-emulsion) process. An optically active macrocyclic building block Sn (IV) meso-tetraphenylporphine dichloride (tin porphyrin) is used to initiate noncovalent self-assembly confined within μ-emulsion droplets. In-situ studies of dynamic light scattering, UV-vis spectroscopy, and electron microscopy, as well as optical imaging of reaction processes suggest an evaporation-induced nucleation and growth self-assembly mechanism. The resulted nanocrystals exhibit uniform shapes and sizes from ten to a hundred nanometers. Because of the spatial ordering of tin porphyrin, the hierarchical nanocrystals exhibit collective optical properties resulting from the coupling of molecular tin porphyrin and photocatalytic activities in the reduction of platinum nanoparticles and networks and in photodegradation of methyl orange (MO) pollutants.

L,L-Type and L,D-type (E)-alkene dipeptide isosteres (EADIs) that have unnatural side chains at the alpha-position were synthesized by the combination of stereoselective aziridinyl ring-opening reactions and organozinc-copper-mediated anti-S(N)2' reactions toward a single substrate of gamma,delta-cis-gamma,delta-epimino (E)-alpha,beta-enoate. The utility of this methodology was demonstrated by the stereoselective synthesis of a set of diastereomeric EADIs of L-Arg-L/D-3-(2-naphthyl)alanine (Nal) that is contained in a small CXCR4 antagonist FC131 [cyclo(-D-Tyr-Arg-Arg-Nal-Gly-)]. Furthermore, a (Nal-Gly)-type EADI was synthesized by samarium diiodide (SmI(2))-induced reduction of a gamma-acetoxy-alpha,beta-enoate. Several FC131 analogues, in which these EADIs were inserted for reduction of their peptide character, were synthesized with analogues containing reduced amide-type dipeptide isosteres to investigate the importance of these amide bonds for anti-HIV and CXCR4-antagonistic activity.

An efficient I2-DMSO reagent system-mediated multicomponent reaction strategy for the synthesis of C3-sulfenylated chromones from o-hydroxyaryl methyl ketones, rongalite, and dimethyl sulfoxide has been developed. Notably, the double C-S bond cleavages of rongalite and dimethyl sulfoxide served as key steps in this smooth transformation, affording the C1 unit and sulfur source for the assembly of C3-sulfenylated chromones. Preliminary mechanistic studies indicated that in situ generated HCHO and (2-(2-hydroxyphenyl)-2-oxoethyl)dimethylsulfonium iodine were probably the key intermediates in this transformation.

Soy protein isolate (SPI) can be used as a carrier for essential oils in active packaging with the purpose of inhibiting the growth of spoilage microorganisms on food and extending food storage time. This study assessed the effect of adding thyme essential oil (TEO) on the physical properties, antioxidant activity, and antibacterial properties of thyme essential oil films (TEOF) using SPI as the film-forming matrix. The results indicated that the property of the composite film is improved after adding TEO. Scanning electron microscopy (SEM), infrared spectroscopy and X-ray diffraction (XRD) were used to analyze the better compatibility of the film matrix. Antibacterial experiments showed that the addition of TEO resulted in a stronger inhibitory effect of the composite film on Staphylococcus aureus and Escherichia coli. Furthermore, the results of the cherry tomato packaging test demonstrated that the film with concentration of 2.4 g/100 g TEO had the best preservation effect during storage, which could delay the decay, providing a reference for its application in food packaging.