Modulating confinement space in metal-organic frameworks enables highly selective indole C3-formylation.

Here, Selective C3-formylation of indole was achieved under mild conditions using a metal-organic framework (MOF) catalyst. The confined reaction space within the MOF pores effectively suppressed undesired side reactions and promoted the formation of the targeted product by controlling the reaction pathway. Density functional theory (DFT) calculations corroborated the experimental observations.

A highlightedly improved method for isolating and characterizing calcium oxalate crystals from tubercles of Mammillaria schumannii.

BACKGROUND: Calcium oxalate (CaOx) is the most prevalent and widespread biomineral in plants and is involved in protective and/or defensive functions against abiotic stress factors. It is, however, expected that this function has an extremely significant contribution to growth processes in plants bearing large amounts of CaOx, such as cacti growing in desert environment. RESULTS: In our research, small-sized CaOx crystals (≤ 20 µm) with tetrahedral or spherical shapes were observed to dominate in each epidermal and cortical cell from the tubercles of Mammillaria schumannii, a species from the Cereoideae subfamily, having tubercles (main photosynthetic organs) united with adjacent ones almost into ridges on its stem. Because they have potential significant functions, differential centrifugations after mechanical blending were used to obtain these small-sized CaOx crystals, which extremely tend to adhere to tissue or suspend in solution. And then the combined Scanning Electron Microscope Energy Dispersive System (SEM-EDS) and Raman spectroscopy were further performed to demonstrate that the extracted crystals were mainly CaC2O4·2H2O. Interestingly, spherical druses had 2 obvious abnormal Raman spectroscopy peaks of -CH and -OH at 2947 and 3290 cm-1, respectively, which may be attributed to the occluded organic matrix. The organic matrix was further extracted from spherical crystals, which could be polysaccharide, flavone, or lipid compounds on the basis of Raman spectroscopy bands at 2650, 2720, 2770, and 2958 cm-1. CONCLUSIONS: Here we used a highlightedly improved method to effectively isolate small-sized CaOx crystals dominating in the epidermal and cortical cells from tubercles of Mammillaria schumannii, which extremely tended to adhere plant tissues or suspend in isolation solution. And then we further clarified the organic matrix getting involved in the formation of CaOx crystals. This improved method for isolating and characterizing biomineral crystals can be helpful to understand how CaOx crystals in cacti function against harsh environments such as strong light, high and cold temperature, and aridity.

Utilizing ferrocene for doping iron into graphitic carbon nitride (FeIII/g-C3N4): an internal dual photocatalyst for tandem oxidation/cyclization of toluene to benzimidazoles under visible light conditions.

Recently, doping metals into graphitic carbon nitride (g-C3N4) is considered for environmental applications and organic reactions. In this study, we used ferrocene as a source of Fe3+ to dope iron onto g-C3N4. The scaffold of the internal electric field is presented as an impressive strategy to increase photocatalytic activities. Fe3+ was doped onto graphitic carbon nitride (FeIII/g-C3N4) by the calcination method, which was well characterized by FT-IR, Raman, XRF, XRD, XPS, UV-visible DRS, photo-luminescence (PL), photocurrent, SEM, HR-TEM, EDX, BET, EIS, and cyclic voltammetry analyses. The synthesis of benzimidazole derivatives as pharmaceutically active compounds was introduced by using a suitable method under mild reaction conditions without using a base, oxidant, and other reagents or additives. The modification by using iron had a considerable effect on the optical and electronic characteristics in contrast to g-C3N4. The nanocomposite FeIII/g-C3N4 could be employed as a multifunctional photocatalyst to perform the tandem process, oxidation of toluene, and then cyclization with o-phenylenediamines to prepare benzimidazoles under visible light conditions. The existence of the dynamic equilibrium of Fe3+/Fe2+ helped in significantly improving the activity. By changing the reaction conditions and different control experiments as well as Mott-Schottky plot analysis, the superoxide ion (O2˙-) can be obtained as the reactive species in this reaction. The photocatalytic activity of FeIII/g-C3N4 for this one-pot reaction is also investigated in detail.

High Catalytic Activity of C60 Pdn Encapsulated in Metal-Organic Framework UiO-67, for Tandem Hydrogenation Reaction.

Metal nanoparticles (NPs) stabilized by MOFs are very promising for catalysis, whereas introduction of C60 into MOFs has been very rarely used, and there was no report for their cooperative catalysis in organic syntheses. In this work, C60 @UiO-67 was synthesized by a one-pot method, so that C60 is uniformly distributed on UiO-67 in molecular form. Pd NPs coordinating with C60 have been successfully embedded into the framework. The obtained multifunctional C60 Pdn @UiO-67 catalyst exhibits remarkable synergistic catalytic activity in cascade reactions under mild conditions, where UiO-67 affords Lewis acidity and C60 Pdn offers higher hydrogenation activity relative to solely Pd NPs.