Facile construction of fully sp2-carbon conjugated two-dimensional covalent organic frameworks containing benzobisthiazole units

Developing a facile strategy for the construction of vinylene-linked fully π-conjugated covalent organic frameworks (COFs) remains a huge challenge. Here, a versatile condition of Knoevenagel polycondensation for constructing vinylene-linked 2D COFs was explored. Three new examples of vinylene-linked 2D COFs (BTH-1, 2, 3) containing benzobisthiazoles units as functional groups were successfully prepared under this versatile and mild condition. The electron-deficient benzobisthiazole units and cyano-vinylene linkages were both integrated into the π conjugated COFs skeleton and acted as acceptor moieties. Interestingly, we found the construction of a highly ordered and conjugated D-A system is favorable for photocatalytic activity. BTH-3 with benzotrithiophene as the donor with a strong D-A effect exhibited an attractive photocatalytic HER of 15.1 mmol h−1g−1 under visible light irradiation.

Rediscovering the Bacon’s Hydrazine/Phenylhydrazine Mediated Cyclization of 2,2’-Dicarbonylbi(hetero)aryls: Construction of (5-Azo)-/Indazolo[2,3-a]quinolines

The hydrazine/phenylhydrazine mediated reductive dicarbonyl coupling reactions have been carried out under mild condition to arrive the construction of polycyclic aromatic compounds and azo-substituted polyaromatic compounds having a broad substrate...

One-pot Synthesis of Multi-substituted Conjugated Dienones by Trapping Allene Carbocation with Active Ylides

An Rh (II)/boron reagents co-catalyzed unprecedent transformation was established for a rapid construction of multi-substituted conjugated dienones under a mild condition by trapping allene carbocations with oxonium ylides from simple...

Poly(1-halogen-2-phenylacetylenes) Containing Tetraphenylethene Unit: Polymer Synthesis, Unique Emission Behaviours and Application in Explosive Detection

Pd-based catalysts have shown high activity in the polymerization of 1-chloro-2-phenylacetylene monomers in mild condition, but it is still a challenge to find synthetic routes to the polymers with high...

Preparation and Characterization of Novel Polymer-Based Heterogeneous MPg-C3N4 Catalyst and Its Application in Multi-Component Reactions

Magnetic polyvinyl alcohol-based g-C3N4 composite (MPg-C3N4) was synthesized as a heterogeneous catalyst. It was characterized by various analyses such as FT-IR, XRD, FE-SEM, TGA, EDX, and VSM. For showing the catalytic merits of MPg-C3N4, it was used in the synthesis of acridinedione and 4H-chromene derivatives in a highly efficient yield. Various aldehyde derivatives were used to show the merits of the MPg-C3N4. High yield, short reaction time, easy separation, mild condition reaction, simple purification, non-toxic solvents, and reusability are the advantages of using polymer-based heterogeneous MPg-C3N4 catalyst to synthesize acridinedione and 4H-chromene derivatives. Also, the intended products were purified by simple crystallization.

Nature of the Interplay Between Periodontal Diseases and COVID-19

The coronavirus disease 2019 (COVID-19) is mostly a mild condition, however, in some patients, it could progress into a severe and even fatal disease. Recent studies have shown that COVID-19 infection and severity could be associated with the presence of periodontitis, one of the most prevalent chronic diseases. This association could be explained by the fact that periodontitis and COVID-19 share some common risk factors that included chronic diseases, such as diabetes and hypertension as well as conditions such as age, sex, and genetic variants. Another possible explanation could be the systemic inflammation and the aspiration of periodontopathogens seen in patients with periodontitis, which could have a synergism with the virus or compromise the reaction of the body against COVID-19. This narrative review explores the nature of these associations, the evidence behind them, and their implications.

Potential of Transforming Sodalite from Synthesis Kaolin with a Mild Condition of the Hydrothermal Method

The hydrothermal synthesis method is one of the successful methods for transforming kaolin into sodalite with various parameters considered. The variation of alkalinity source of 2-3 Molarity of sodium hydroxide and crystallization time (12-16 hours) was considered an important parameter that influences the formation of sodalite. It is reported in this research that the process of synthesizing sodalite to transform into an amorphous stage (Metakaolinization phase) began with beneficiation of kaolin to remove the impurities and calcination by 6500C for four hours. The synthesis was done through an aging process (400C, 24 hours), and the crystallization temperature was 1000C. The kaolin was characterized by XRD, FESEM, FTIR, PSA, TGA, followed with metakaolin by XRD, FESEM, FTIR, and the end-product by XRD, FESEM, FTIR, and PSA. The crystallinity percentage of sodalite slightly increased by increasing the molarity and crystallization time, but quartz remains in the end-product.