Dipole‐Induced Band‐Gap Reduction in an Inorganic Cage

Metal‐doped polyoxotitanium cages are a developing class of inorganic compounds which can be regarded as nano‐ and sub‐nano sized molecular relatives of metal‐doped titania nanoparticles. These species can serve as models for the ways in which dopant metal ions can be incorporated into metal‐doped titania (TiO₂), a technologically important class of photocatalytic materials with broad applications in devices and pollution control. In this study a series of cobalt(II)‐containing cages in the size range ca. 0.7–1.3 nm have been synthesized and structurally characterized, allowing a coherent study of the factors affecting the band gaps in well‐defined metal‐doped model systems. Band structure calculations are consistent with experimental UV/Vis measurements of the Ti_xO_y absorption edges in these species and reveal that molecular dipole moment can have a profound effect on the band gap. The observation of a dipole‐induced band‐gap decrease mechanism provides a potentially general design strategy for the formation of low band‐gap inorganic cages.     

Solvent‐Driven Chiral‐Interaction Reversion for Organogel Formation

For chiral gels and related applications, one of the critical issues is how to modulate the stereoselective interaction between the gel and the chiral guest precisely, as well as how to translate this information into the macroscopic properties of materials. Herein, we report that this process can also be modulated by nonchiral solvents, which can induce a chiral‐interaction reversion for organogel formation. This process could be observed through the clear difference in gelation speed and the morphology of the resulting self‐assembly. This chiral effect was successfully applied in the selective separation of quinine enantiomers and imparts “smart” merits to the gel materials.     

Total Synthesis of (±)‐Clavilactones A,B, and Proposed D through Iron‐Catalyzed Carbonylation–Peroxidation of Olefin

Biologically significant clavilactones A, B, and the previously proposed D have been synthesized through iron‐catalyzed carbonylation–peroxidation of a 1,5‐diene. Three steps from aldehydes, alkenes, and tert‐butylhydroperoxide build up α,β‐epoxy‐γ‐butyrolactone skeleton as a key building block for synthesis of clavilactone family and its derivatives. Based on our results, the structure of the proposed clavilactone D is not correct and requires revision.     

Dual‐Pore Mesoporous Carbon@Silica Composite Core–Shell Nanospheres for Multidrug Delivery

Monodispersed mesoporous phenolic polymer nanospheres with uniform diameters were prepared and used as the core for the further growth of core–shell mesoporous nanorattles. The hierarchical mesoporous nanospheres have a uniform diameter of 200 nm and dual‐ordered mesopores of 3.1 and 5.8 nm. The hierarchical mesostructure and amphiphilicity of the hydrophobic carbon cores and hydrophilic silica shells lead to distinct benefits in multidrug combination therapy with cisplatin and paclitaxel for the treatment of human ovarian cancer, even drug‐resistant strains.     

An Energy Investigation into 1D/2D Oriented‐Attachment Assemblies of 1D Ag Nanocrystals

In the field of oriented‐attachment crystal growth, one‐dimensional nanocrystals are frequently employed as building blocks to synthesize two‐dimensional or large‐aspect‐ratio one‐dimensional nanocrystals. Despite recent extensive experimental advances, the underlying inter‐particle interaction in the synthesis still remains elusive. In this report, using Ag as a platform, we investigate the van der Waals interactions associated with the side‐by‐side and end‐to‐end assemblies of one‐dimensional nanorods. The size, aspect ratio, and inter‐particle separation of the Ag precursor nanorods are found to have dramatically different impacts on the van der Waals interactions in the two types of assemblies. Our work facilitates the fundamental understanding of the oriented‐attachment assembling mechanism based on one‐dimensional nanocrystals.     

Efficient Water Oxidation Catalyzed by Mononuclear Ruthenium(II) Complexes Incorporating Schiff Base Ligands

Four new charge‐neutral ruthenium(II) complexes containing dianionic Schiff base and isoquinoline or 4‐picoline ligands were synthesized and characterized by NMR and ESI‐MS spectroscopies, elemental analysis, and X‐ray diffraction. The complexes exhibited excellent chemical water oxidation activity and high stability under acidic conditions (pH 1.0) using (NH₄)₂Ce(NO₃)₆ as a sacrificial electron acceptor. The high catalytic activities of these complexes for water oxidation were sustained for more than 10 h at low concentrations. High turnover numbers of up to 3200 were achieved. A water nucleophilic attack mechanism was proposed. A Ru^V?O intermediate was detected during the catalytic cycle by high‐resolution mass spectrometry.     

Taming Living Carbocations in Catalytic Direct Conjugate Addition of Simple Alkenes to α,β‐Enones

A Lewis acid in the presence of an anionic phosphate ligand enables the addition of alkenes to α,β‐enones. The ligand facilitates selective β‐proton elimination by suppressing competing pathways, thus leading to vinylation adducts in high yields (up to 99 %) for a broad range of substrates.     

Characterization of chitosan microparticles reinforced cellulose biocomposite sponges regenerated from ionic liquid

The chitosan-microparticles reinforced cellulose biocomposite sponges regenerated from ionic liquid were prepared and characterized. Fourier transform infrared (FTIR) spectroscopy confirmed that the cellulose dissolved in 1-allyl-3-methylimidazolium chloride without derivatization. Chitosan particles as reinforcement were incorporated into the cellulose matrix. FTIR spectra indicated hydrogen bonding between hydroxyl groups of cellulose and chitosan. The biocomposite sponges showed uniform three-dimensional interconnected porous structures. The breaking strength of the sponges increased significantly, from 0.09 to 0.32 MPa with the addition of 1.0 wt% chitosan. The sponges also demonstrated excellent antibacterial activity against S. aureus and E. coli with the average inhibition zone diameters >2 mm and the inhibition rate higher than 80 %. Furthermore, the biocomposite sponges exhibited good moisture penetrability and high porosity. The water uptake ability of the sponge was >25 times of its weight in water with a fast swelling. The chitosan/cellulose composite sponge is expected to be a promising material for potential applications as wound dressing.     

紫外分光光度法同时测定喹啉、吲哚、联苯的含量

采用了紫外分光光度法同时对喹啉、吲哚、联苯3组分的含量进行测定。根据喹啉、吲哚、联苯的紫外吸收光谱特征,确定266,290和313nm 3个波长作为测定波长。研究表明,在0~12 mg/L范围内,浓度和吸光度呈良好线性关系;266,290和313nm波长处喹啉、吲哚、联苯的吸光度具有较好的加和性,适用于多组分的同时测定;喹啉、吲哚、联苯的相对标准偏差分别为1.6%,1.0%,0.76%,采用标准加入法对3种物质进行了回收实验,回收率分别为98.5%~100.6%,97.5%~101.8%,98.8%~102.0%。     

Determination of bisphenol A, 4‐octylphenol,and 4‐nonylphenol in soft drinks and dairy products by ultrasound‐assisted dispersive liquid–liquid microextraction combined with derivatization and high‐performance liquid chromatography with fluorescence detection

A novel hyphenated method based on ultrasound‐assisted dispersive liquid–liquid microextraction coupled to precolumn derivatization has been established for the simultaneous determination of bisphenol A, 4‐octylphenol, and 4‐nonylphenol by high‐performance liquid chromatography with fluorescence detection. Different parameters that influence microextraction and derivatization have been optimized. The quantitative linear range of analytes is 5.0–400.0 ng/L, and the correlation coefficients are more than 0.9998. Limits of detection for soft drinks and dairy products have been obtained in the range of 0.5–1.2 ng/kg and 0.01–0.04 μg/kg, respectively. Relative standard deviations of intra‐ and inter‐day precision for retention time and peak area are in the range of 0.47–2.31 and 2.76–8.79%, respectively. Accuracy is satisfactory in the range of 81.5–118.7%. Relative standard deviations of repeatability are in the range of 0.35–1.43 and 2.36–4.75% for retention time and peak area, respectively. Enrichment factors for bisphenol A, 4‐octylphenol, and 4‐nonylphenol are 170.5, 240.3, and 283.2, respectively. The results of recovery and matrix effect are in the range of 82.7–114.9 and 92.0–109.0%, respectively. The proposed method has been applied to the determination of bisphenol A, 4‐octylphenol, and 4‐nonylphenol in soft drinks and dairy products with much higher sensitivity than many other methods.