Immobilization of Ag and Pd over a novel amide based covalent organic framework (COF-BASU2) as a heterogeneous reusable catalyst to reduce nitroarenes

Reducing nitroarenes to their amines is among the common and vital reactions with remarkable industrial significance. This study describes an eco-friendly recyclable catalyst for reducing nitroarene. For this purpose, a new strategy was designed to synthesize a new amide-based COF through the reaction between 1,4‑diaminobenzene and trimesic acid (BTC). In this synthesis pathway, BTC is activated with carbonyl diimidazole (CDI), followed by its reaction with 1,4-diaminobenzene. Eventually, the desired COF (i.e., COF-BASU2) is synthesized. Next, it is decorated via silver (Ag) and palladium (Pd) ions to synthesize Ag/COF-BASU2 and Pd/COF-BASU2. The as-synthesized materials are properly characterized through ICP-OES, TG-DTA, FT-IR, EDX, XRD, TEM, and N2 isotherms. The simulation results have suggested a multi layers of two dimensional frameworks of COF-BASU2. Furthermore, Ag and Pb ions have shown to be placed on the surface and between the layers of COF, respectively. Then, we used molecular hydrogen as a reducing agent to investigate the Pd/COF-BASU2′s catalytic activity for nitroaromatic hydrogenation with excellent chemoselectivity and wide scope. In addition, NaBH4 was used as a reductant along with Ag/COF-BASU2 to reduce the nitro group on electronically diversified nitroarenes selectively. The remarkable characteristics of this catalytic system are the great turnover number (TON), considerably high selectivity, good turnover frequency (TOF), high yield, fast and almost complete conversion of nitrobenzene to the desired aniline, and facile and convenient segregation of catalyst and product. According to the obtained results, using Ag/COF-BASU2 offers the highest yields in the shortest reaction time

The methanol extract of red algae, Dichotomaria obtusata, from Persian Gulf promotes in vitro osteogenic differentiation of bone marrow mesenchymal stem cells; a biological and phytochemical study

OBJECTIVES: Osteoporosis is a major public health problem that is appeared with increasing age. This study evaluated the effect of the algae Dichotomaria obtusata methanol extract on osteogenic differentiation of the cultured bone marrow mesenchymal stem cells (BMMSCs) in vitro and analyzed the algae methanol extract to find out the potent beneficial components. METHODS: Dichotomaria obtusata were collected from the coastal area of Bushehr City in the Persian Gulf, Iran. The expression of osteogenesis-related genes was examined using real-time PCR. The formation of calcium deposits in differentiated MSCs was examined by Alizarin R staining. Analyses of algae extract ingredients were performed by gas chromatography-mass spectrometry (GC-MS). KEY FINDINGS: Methanol extract of the algae caused the up-regulation of osteogenic genes that were significant for Osteopontin and Osteocalcin (P < 0.05) and also led to an increase in calcium deposits and matrix mineralization in BMMSCs. The GC-MS analyses of the algae extracts resulted in the identification of steroids and essential fatty acids. CONCLUSION: The results of the study indicated that the methanol extract of D. obtusata may possess significant potentials for the prevention of osteoporosis in vitro

Pd(II)-immobilized on a novel covalent imine framework (COF-BASU1) as an efficient catalyst for asymmetric Suzuki coupling

This study reports the synthesis of a new imine-based covalent organic framework (COF) stabilizer through the reaction between 1,4-phenylenediamine and 4,4′,4″-(benzene-1,3,5-triyltris(oxy))tribenzaldehyde (COF-BASU1). Next, palladium (Pd) species were decorated on the synthesized COF, and the obtained Pd/COF-BASU1 composite was used as a heterogeneous catalyst in the asymmetric Suzuki-Miyaura coupling (SMC) reaction. The easily prepared imine-linked COF-BASU1 possesses a two-dimensional eclipsed layered-sheet structure, making its incorporation with metal ions feasible. Via a simple post-treatment, a Pd(II)-containing COF, Pd/COF-BASU1, was accordingly synthesized, which showed excellent catalytic activity in catalyzing the asymmetric Suzuki-Miyaura coupling reaction with high stereoselectivity. The eclipsed imine structure provide chiral environment to achieve the asymmetric Suzuki-Miyaura coupling reactionplay. Afterward, the chiral high-performance liquid chromatography (HPLC) was conducted to examine the axially chiral products generated through these reactions. These products were separated via the HPLC method. This technique is based on the function of some columns whose packing groups can segregate chiral products. The fabricated nanocatalyst was structurally authenticated using various analytical techniques such as FT-IR, XRD, FE-SEM, TGA, EDS, ICP-AES, and BET. The outcomes indicated that Pd/COF-BASU1 nanocomposite is a suitable catalyst to synthesis axially chiral biaryl derivatives with high stereoselectivity (up to 85.37% ee)