Synthesis of gem-Difluoro-3,4-dihydro-2H-pyrans via a TfOH-Catalyzed [4 + 2] Annulation of Difluoroenoxysilanes with α-Cyano Chalcones.

Difluoroenoxysilane, a commonly used difluoroallylating reagent, has attracted considerable attention in recent years. However, its application in the annulation reaction for the construction of fluorinated heterocyclic compounds remains relatively limited. Presented here is the Brønsted acid-catalyzed efficient formal [4 + 2] annulation of difluoroenoxysilanes with α-cyano chalcones. The developed protocol demonstrates tolerance to various substituents under mild reaction conditions, providing a reliable approach to construct gem-difluoro-3,4-dihydro-2H-pyrans in good to excellent yields with high diastereoselectivities.

Oxygen Vacancy-Mediated CuWO4/CuBi2O4 Samples with Efficient Charge Transfer for Enhanced Catalytic Activity toward Photodegradation of Pharmacologically Active Compounds.

Photocatalytic degradation is a promising method for controlling the increasing contamination of the water environment due to pharmacologically active compounds (PHACs). Herein, oxygen vacancy (OV)-modulated Z-scheme CuWO4/CuBi2O4 hybrid systems were fabricated via thermal treatment by loading of CuWO4 nanoparticles with OVs on CuBi2O4 surfaces. The synthesized CuWO4/CuBi2O4 hybrid samples exhibited an enhanced photodegradation ability to remove PHACs under visible-light irradiation. More importantly, an optimized sample (10 wt % CuWO4/CuBi2O4) exhibited superior catalytic activity and excellent recycling stability for PHAC photodegradation. In addition, possible degradation paths for PHAC removal over the CuWO4/CuBi2O4 hybrid systems were proposed. The enhanced photocatalytic performance could be attributed to the efficient separation and transfer of photoformed charge pairs via the Z-scheme mechanism. This Z-scheme mechanism was systematically analyzed using trapping experiments of active species, ultraviolet photoelectron spectroscopy, electron spin resonance, and the photodepositions of noble metals. The findings of this study can pave the way for developing highly efficient Z-scheme photocatalytic systems for PHAC photodegradation.

Synthesis of Fluoro 3(2H)-Furanones via a TFA-Catalyzed Dehydrofluorinative Cyclization of 2,2-Difluoro-3-hydroxy-1,4-diketones.

A TFA-catalyzed dehydrofluorinative cyclization of 2,2-difluoro-3-hydroxy-1,4-diketones has been developed in the presence of amines under mild conditions in which the difluorinated substrates are readily prepared according to our reported literature. This protocol provides a rapid construction of fluoro 3(2H)-furanones in good to excellent yields with good functional group tolerance. Easy scale-up synthesis also shows a practical advantage.

Z-scheme MnO2/Mn3O4 heterojunctions with efficient peroxymonosulfate activation for organic pollutant removal.

The exploration of efficient heterogeneous catalysts for persistent organic pollutant removal is extremely attractive. In the present work, MnO2/Mn3O4 photo-Fenton catalysts were designed by a facile hydrothermal route to activate peroxymonosulfate (PMS) under visible light irradiation for organic pollutant degradation. The optimized MnO2/Mn3O4 heterojunction shows excellent Rhodamine B (RhB) removal efficiency, whose apparent kinetic constant is 11.9 and 5.36 times as high as the MnO2 and Mn3O4. Meanwhile, there is a neglectable attenuation in catalytic performance after 5 recycling runs. Based on the active species trapping experiments, the non-radical process contributes more than the radical process during RhB degradation. Moreover, factors including the dosage of PMS, initial RhB concentration, initial pH, the presence of various anions, different organic pollutants, and water sources are investigated. Systematical characterizations reveal that the enlarged specific surface areas and the efficient charge separation aroused from the Z-scheme mechanism are attributed to the enhanced photo-Fenton performance. The present work contributes to the construction of the Mn-based photo-Fenton catalyst with efficient PMS activation capacity for environmental remediation.

Direct Z-scheme 1D/2D WO2.72/ZnIn2S4 hybrid photocatalysts with highly-efficient visible-light-driven photodegradation towards tetracycline hydrochloride removal.

There are increasing environmental concerns of serious pollution from emission of antibiotic wastewater. Herein, a series of direct Z-scheme WO2.72/ZnIn2S4 (WOZIS) hybrid photocatalysts composed of one-dimensional (1D) WO2.72 (WO) nanorods and two-dimensional (2D) ZnIn2S4 (ZIS) nanosheets have been designed and constructed for tetracycline hydrochloride (TCH) degradation without presence of solid-state electron mediators. The crystalline phase, chemical composition, morphology, optical properties and photocatalytic activity of the as-prepared samples were characterized by the XRD, XPS, SEM, HRTEM, BET, UV-vis DRS, and PL. Obviously, all the WOZIS hybrid photocatalysts exhibited significantly enhanced photocatalytic activity towards TCH degradation. Meanwhile, WOZIS-1 sample with WO/ZIS molar ratio of 1:1 showed the highest photocatalytic activity. The significantly enhanced photoactivity of WOZIS hybrid photocatalyst was due to Z-scheme charge separation mechanism based on the build of tight interfacial contacts between WO nanorods and ZIS nanosheets, thereby driving efficient charge separation. Moreover, the high photocatalytic stability of as-prepared WOZIS-1 hybrid sample was revealed through seven successive cycling reactions.

Ruthenium-catalyzed decarboxylative C-S cross-coupling of carbonothioate: synthesis of allyl(aryl)sulfide.

A novel ruthenium-catalyzed decarboxylative cross-coupling of carbonothioate is disclosed. This method provides straightforward access to the corresponding allyl(aryl)sulfide derivatives in generally good to excellent yields under mild conditions and features a broad substrate scope, wide group tolerance and in particular, no need to use halocarbon precursors.

1-[4-(Difluoro-meth-oxy)phen-yl]-N-(3,4-dimeth-oxy-phen-yl)-1H-1,2,4-triazole-3-carboxamide.

Two crystallographically independent mol-ecules, A and B, with similar conformations are present in the asymmetric unit of the title compound, C(18)H(16)F(2)N(4)O(4). In mol-ecule A, the plane of the 1,2,4-triazole ring is tilted relative of the 4-difluoro-meth-oxy-substituted and the 3,4-dimeth-oxy-substituted benzene rings by 6.5 (2) and 16.4 (1)°, respectively. The -CHF(2) group is twisted away from the plane of the benzene ring, with a dihedral angle between the O-C bond of the OCHF(2) group and the plane of the adjacent phenyl ring of 38.6 (3)°. The corresponding parameters for mol-ecule B are 7.7 (1), 9.5 (2) and 25.2 (2)°. In both mol-ecules, the conformations are stabilized by intra-molecular N-H⋯N and C-H⋯O hydrogen bonds. There are also C-H⋯π contacts between the methyl groups and the benzene rings, and π-π stacking inter-actions between the benzene rings of adjacent parallel A mol-ecules [centroid-centroid distance = 3.8942 (17) Å]. π-π inter-actions are also observed between the triazole ring and one of the benzene rings of parallel B mol-ecules [centroid-centroid distance = 3.7055 (16) Å].

1-[4-(Difluoromethoxy)phenyl]-N-(2,3-dimethylphenyl)-1H-1,2,4-triazole-3-carboxamide.

In the mol-ecule of the title compound, C(18)H(16)F(2)N(4)O(2), the 1,2,4-triazole ring forms dihedral angles of 3.6 (2) and 14.9 (6)° with the 4-difluoro-meth-oxy-substituted benzene ring and the 2,3-dimethyl-substituted benzene ring, respectively. The OCHF(2) group is twisted away from the plane of the benzene ring, as shown by the C-O-C-C torsion angle of 145.8 (2)°. The conformation is stabilized by an inter-molecular N-H⋯N hydrogen bond. In the crystal, short C-H⋯O inter-actions lead to chains of mol-ecules.