Latest ArticlesAn Ir-catalyzed selective mono-sulfamidation of 2-arylquinazolinones has been achieved with a low catalyst loading under mild conditions. A series of regioselective mono-sulfamided 2-arylquinazolinones were obtained in up to 90% yields. Compared with our previous work of constructing di-sulfamidated 2-arylquinazolinones, the mono-sulfamided products could be obtained selectively by changing the ratio of substrates, the loading of catalyst, acid additive, and reaction time.
Nitrous oxide (N2O) is one of the significant greenhouse gases, and partial nitritation-anammox (PNA) process emits higher N2O than traditional nitrogen removal processes. N2O production in PNA mainly occurs in three different pathways, i.e., the ammonia oxidizing bacteria (AOB) denitrification, the hydroxylamine (NH2OH) oxidation and heterotrophic denitrifiers denitrification. N2O emission data vary significantly because of the different operational conditions, bioreactor configurations, monitoring systems and quantitative methods. Under the common operational parameter scopes of PNA, N2O emission via NH2OH oxidation dominates at relatively low dissolved oxygen (DO), low inorganic carbon (IC), high pH or low NO2- concentration, while N2O emission via AOB denitrification dominates at relative higher DO, higher IC, lower pH or higher NO2- concentration. AOB are highly enriched while nitriteoxidizing bacteria (NOB) are rarely found in partial nitritation process, and the order Nitrosomonadales of AOB is the dominant group and N2O producer. Anammox bacteria, AOB and certain amount of heterotrophic denitrifying bacteria are observed in the anammox process, the genus Denitratisoma and the heterotrophic denitrifying bacteria in the deep layer of anammox granules are the dominant N2O generation bacteria. In one-stage PNA reactors, anammox bacteria account for a large fraction of the biomass, AOB account for small portion, and NOB account for even less. The microbial community, diversity and N2O producers in one-stage PNA reactors are similar with those in two-stage PNA reactors. The dominant anammox bacteria, AOB and NOB in PNA are the species Candidatus Brocadia, the genera of Nitrotoga, Nitrospira and Nitrobacter, and the genus Nitrosomonas, respectively. The relations between N2O emission pathways and microbial communities need further study in the future.
CO2-controlled assembly of conjugated polymer and boron nitride (BN) was fabricated via electrostatic and hydrophobic interactions between the BN fiber and conjugated polymer of PFBT containing fluorene units and 2, 1, 3-benzothiadiazole units. CO2, an effective and green stimulus for regulating the assembly of PFBT and BN fibers, leads to an obvious fluorescence variation. Moreover, PFBT enables the assembly with the signal amplification and light-harvesting properties. This work provides a new triggering method to construct intelligent conjugated polymer-based platform, and offers fluorescence monitoring strategy for carbon dioxide capture.
The condensation reaction of ω-aminoalkyleneamide-functionalized pillar[5]arenes with 2-(4-([2, 2':6', 2''-terpyridin]-4'-yl)phenoxy)acetic acid or 4-(4-([2, 2':6', 2''-terpyridin]-4'-yl)phenoxy)butanoic acid in dry chloroform at room temperature under the catalysis of HOBT/EDCl resulted in novel pillar[5]arene diamido-bridged terpyridine derivatives. 1H NMR and 2D NOESY spectra clearly indicated that the interesting [1]rotaxanes were formed by longer alkylene such as propylene, butylene and hexylenediamido chains threading into the cavity of the pillar[5]arene and with larger terpyridine acting as the stopper. However, the shorter ethylenediamido chain only exists outer of cavity of pillar[5]arene and the molecule exist on free form.
A new artificial transmembrane channel molecule bearing dihydrogen phosphate groups has been synthesized. The terminal dihydrogen phosphate groups enable the channel to be highly negatively charged at both ends of the channel structures. The artificial channel could incorporate into the lipid bilayer efficiently under low concentration. The channel displays high NH4+/K+ selectivity due to the electrostatic interaction and hydrogen bonding between NH4+ and the terminal dihydrogen phosphate groups.
Novel highly sensitive chiral organic field-effect transistors (COFET) were developed by directly assembling imidazolium3, 5-dimethylphenylcabamoylated-β-cyclodextrin(Im+-Ph-β-CD)and 3, 5-dimethylphenylcarbamoylated-β-CD (Ph-β-CD) respectively onto the semiconductor layer as sensing units. The Im+-Ph-β-CD/COFET afforded better enantioselectivity and a lowest detection concentration of 10 18 L/mol as well as the potentiality in quantitative analysis of commercial medicines.
Graphene-like C3N4/Ag3PO4 photocatalysts are synthesized by calcination and solutions precipitating method. The obtained g-C3N4/Ag3PO4 composites display excellent photocatalytic activity for the degradation of methylene orange (MO), rhodamine B (RhB) and tetracycline (TC) under visible light irradiation. The solutions containing RhB (10 mg/L) and MO (10 mg/L) can be efficiently degraded within 15 min and 30 min. Especially, nearly 80% of TC (50 mg/L) is degraded within 20 min, which are much better than those of pure g-C3N4 nanosheets and Ag3PO4, implying that strong interaction and reasonable energy band alignment in the contact interface can effectively transfer the carries. Furthermore, the g-C3N4/Ag3PO4 composites exhibit the improved stability, and only a slight decrease is observed after three recycling runs. Moreover, the impact of inorganic ions and PH values on the degradation performance is rather small. The Z-scheme photocatalytic mechanism of the g-C3N4/Ag3PO4 composites based on the active species trapping experimental is proposed. This work demonstrates the promising applications of the g-C3N4/Ag3PO4 composites in environmental issues.
A new and convenient visible-light-induced method has been developed for the synthesis of sulfonylated benzofurans via oxidative cyclization reaction of 1, 6-enynes and arylsulfinic acids. This reaction was carried out under metal-free and mild conditions, in which the C-S, C-C and C=O bonds could be sequentially formed in one pot operation.
Although intelligent hydrogels have shown bright potential application in biomedical fields, they were prepared by conventional methods and still face many serious challenges, such as uncontrollable stimulus-response and low response sensitivity. Recently, RAFT polymerization provides a versatile strategy for the fabrication of intelligent hydrogels with improved stimulus-response properties, owing to the ability to efficiently construct hydrogel precursors with well-defined structure, such as block copolymer, graft copolymer, star copolymer. In this review, we summarized the recent progress on intelligent hydrogels based on RAFT polymerization with emphasis on their fabrication strategies and applications for controlled drug delivery.
The enantioselective total synthesis of the putative structure of versiquinazoline H and three diastereomers has been achieved, which allowed the revision of the stereochemistry of this natural product. This six-step total synthesis relied on the evolution of the strategy that we previously developed, which features a DMDO-triggered tandem reaction. The modification of the lactamization step resulted in a significant improvement of yield that ensured the efficient total synthesis.
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