The new compound 2-O-β-D-fructofuranosylglycerol was isolated from the hexane residue. Also 2-O-methylα-fructofuranoside was isolated for the first time from the fruits of Pyrus amygdaliformis Vill. The chemical structure of isolated carbohydrates were identified using NMR, Mass spectroscopic technique and literature data. The Minimal Inhibitory Concentrations (MIC) of P.amygdaliformis Vill. Hexane, dichloromethane and butanol extracts of fruits were used for the test microorganisms. Hexane extract showed antimicrobial activity against Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis and Salmonella typhimurium with MIC range between 25 -0.39 mg/ml. The most sensitive strain was found to be Klebsiella pneumoniae with MIC value at 0.39 mg/ml in Hexane extract.

In this study, photoinitiated cationic polymerization of epoxy resins by photoinduced electron transfer reactions using four new chromophoric dyes, namely (3E)‐1,1′‐bis(2‐ethylhexyl)‐6,6′‐dipyren‐1‐yl‐3,3′‐biindole‐2,2′(1H,1′H)‐dione (ISOIV), (3′E)‐1,1′′′‐diethyl‐1′,1′′‐bis(2‐ethylhexyl)‐1H,1′′′H‐5,6′:3′,3′′:6′′,5′′′‐quaterindole‐2′,2′′(1′H,1′′H)‐dione (ISOV), (3E)‐6,6′‐bis(9‐ethyl‐9H‐carbazole‐3‐yl)‐1‐[(2R)‐2‐ethylhexyl]‐1′‐[(2S)‐2‐ethylhexyl]‐3,3′‐biindole‐2,2′(1H,1′H)‐dione (ISOVIII) and 3,3′‐(6‐bromokinoksalin‐2,3‐diyl)bis(9‐ethyl‐9H‐carbazole) (TPDC6), and diphenyliodonium hexafluorophosphate (Ph2I+PF6−; DPI) under sunlight is reported. Upon irradiation, photoexcited dye forms an exciplex with DPI. Electron transfer reactions within the exciplex result in the formation of ionic species capable of initiating ring‐opening polymerization of an epoxy resin. It is shown that among the investigated dyes, ISOVIII and TPDC6 exhibited higher initiation efficiency in accordance with their stronger electron‐donating nature due to the presence of carbazole groups. © 2021 Society of Industrial Chemistry.

Controlling thin-film crystallization kinetics of perovskites is vital for the fabrication of highly efficient and stable perovskite solar cells (PSCs). Because of the low solubility of lead halogen derivatives in dimethylformamide solvent and poor film quality, addition of dimethylsulfoxide (DMSO) to the solution as a cosolvent has a great effect on the crystallization kinetics and morphology of perovskite thin films. However, Pb-DMSO and residual DMSO complexes that are difficult to be removed from the structure can lead to structural deformations and stability issues. Here, two different reagents such as benzyl chloride (BCl) and benzyl bromide (BBr) are applied as antisolvents to eliminate these problems utilizing the Kornblum oxidation reactions in the triple-cation perovskite thin films formed by the one-step coating method. Electrochemical impedance spectroscopy (EIS) analysis has been carried out to explain the charge transfer resistances and capacitive behaviors under illuminated conditions. EIS measurements show that washing with BBr antisolvent reduces the charge recombination in PSCs and leads to the best device performance with improved charge transport, yielding a 19.2% power conversion efficiency with a higher open circuit voltage (V oc ) of 1100 mV compared to washing with chlorobenzene (CB) and BCl. Resistances at the low-frequency region in Nyquist complex plots associated with charge recombination resistances were measured to be 1430, 564, and 3000 ohm, which are in good agreement with short circuit currents 23.3, 23.1, and 24.8 mA/cm 2 for devices fabricated with CB, BCl, and BBr, respectively. Removal of the residual DMSO and Pb-DMSO complexes via washing with BBr results in achieving more stable and highly efficient solar cells, which maintained 94% of the initial efficiency after 1 month.

No abstract

Heterocyclic compounds have played significant roles in achieving high performance as hole transport materials (HTMs) for perovskite solar cell (PSC) applications. Various studies have focused on the development of fused heterocyclic conjugated structures for hole transport materials. In this report, three novel π-extended conjugated materials (M1-M3), based on thieno[3,2-b]thiophene (TT) and 4,4′-dimethoxytriphenylamine [TPA(OMe)2], were designed and successfully synthesized via Palladium (0) catalyzed Suzuki coupling reaction. Their optical, electrochemical, and thermal properties were investigated by UV-Vis, fluorescence, cyclic voltammetry, and thermal analysis. The materials were utilized as hole transport materials in p-i-n architecture perovskite solar cells, which displayed performances of open-circuit voltage (Voc) as high as 1,050 mV, a maximum short-circuit current (Jsc) of 16,9 mA/cm2, a maximum fill factor (FF) of 29.3%, and a power conversion efficiency (PCE) of 5.20%. This work demonstrated that thieno[3,2-b]thiophene and TPA(OMe)2-based structures are promising cores for high-performance hole transport materials in perovskite solar cell architecture.

β-D-Fructopyranose (1), D-Xylopyranose (2), D-Mannitol (3), and flavonoids including quercetin-3-α-L-arabinofuranoside (4) and quercetin-3-O-glucopyranoside (5) were isolated from the leaves of Rhododendron luteum for the first time. Isolated compounds were identified using 1D NMR ( 1 H-NMR, 13 C-NMR) and 2D NMR (HMBC, HSQC, COSY) spectroscopic techniques and comparison of the literature data. In our study, relatively high amount of Quercetin-3-O-glucopyranoside was isolated. (4%) As a result, our research showed that leaves of Rhododendron luteum could be a good source of monosaccharide, sugar alcohols and bioactive flavonoid glycosides.

No abstract

No abstract