Effect of CH3NH3I/CH3NH3Br precursors on the structural and surface morphology properties of the electrodeposited methylammonium lead–mixed halide perovskite films

Journal of Solid State Electrochemistry - Organometallic halide perovskites have been arisen as a class of multi-purpose materials with exciting applications in optoelectronic devices such as solar...     

Nano-SiO2 catalyzed three-component preparations of pyrano[2,3-d]pyrimidines, 4H-chromenes,and dihydropyrano[3,2-c]chromenes

An efficient one-pot three-component procedure has been developed for the preparation of tetrahydrobenzo[b]pyrans, dihydropyrano[3,2-c]chromenes, and pyrano[2,3-d]pyrimidines using nano-SiO₂ as catalyst in H₂O at 70 °C. This methodology has a number of advantages such as: use of reusable catalyst, easy access, short reaction times, high yields, easy work up and use of non-toxic and green solvent.     

Interaction of an intermediate structure of Bacillus subtilis α-amylase with alkyl-substituted sepharose 4B

An intermediate form of alpha-amylase from Bacillus subtilis was prepared following a previously reported procedure. Stabilization of this protein structure by various additives and its interaction with alkyl-substituted Sepharose 4B (Sepharose-lipid), used to mimic the role of the alkyl chains of the phospholipid bilayer, were investigated. Exposure of hydrophobic clusters in the protein structure on denaturation was indicated by a greater affinity of the intermediate form for interaction with the alkyl chains on the matrix, as compared with the original native structure. Near- and far-ultraviolet circular dichroism studies supported loss of tertiary structure with retention of secondary structure, as expected from molten globular intermediate forms. Based on the results presented, we suggest that interaction of a protein in its native and nonnative forms with an alkyl-substituted matrix may provide useful information regarding its capacity for insertion into and translocation across the biologic membrane.     

A one-pot three-component reactions for the synthesis of fully substituted spiro indeno[1,2-b]quinoxaline derivatives

An efficient and simple approach of the synthesis of some spiro indeno[1,2-b]quinoxalines via a one-pot three-component reaction of 11H-indeno[1,2-b]quinoxalin-11-one, pyrazolone, and malononitrile in the presence of Na₂CO₃ at 70 °C is reported. This reaction has shown to have high atom economy.     

Synthesis of New Multibenzo Oxygen–Sulfur Donor Macrocycles Containing Lactams at Room Temperature

Some new oxygen–sulfur, multibenzo macrocyclic ligands containing amide groups have been prepared using the macrocyclization process with the reaction of 2,2′-thiobis-[4-methyl(2-aminophenoxy)phenyl ether] as a symmetrical diamine with appropriate dicarboxylicacid dichlorides in moderate yields. This macrocyclization led to the formation of di- and tetramide macrocycles. These reactions were routinely carried out at ambient temperature in CH₂Cl₂ as solvent in high dilution without template effect conditions. It is found that sulfur the atom affects the rigidity of the macrocycles and diastereotopicity of nuclei in the ring of these series of macrocyclic compounds.     

A comparison of two formulations of the fin efficiency for straight fins

A formulation of the fin efficiency based on Newton’s law of cooling is compared with a formulation based on a ratio of heat transferred from the fin surface to the surrounding fluid to the heat conducted through the base.The first formulation requires that the solution of the nonlinear fin equations for constant heat transfer coefficient and constant thermal conductivity is known,whilst the second formulation of the fin efficiency requires only that a first integral of the model equation is known.This paper shows the first formulation of the fin efficiency contains approximation errors as only power series and approximate solutions to the nonlinear fin equations have been determined.The second formulation of the fin efficiency is exact when the first integrals can be determined.