Effect of inclusion complexation on the photophysical behavior of diphenylamine in β-cyclodextrin medium: a study by electronic spectra

Spectral characteristics of diphenylamine (DPA) have been investigated in β-cyclodextrin (β-CDx) solution. The formation of the complex was revealed by UV, steady state and time-resolved fluorescence spectroscopy. The stoichiometry of DPA:β-CDx complex, determined using Benesi-Hildebrand equation and Job's continuous variation method is 1:1. The binding constants calculated from various methods are reported. This inclusion complex formation from DPA and β-CDx was also confirmed by the FT-IR spectral study and SEM image analysis of solid complex prepared by co-precipitation method.     

Asymmetric Synthesis of Simplactones A and B

A new, simple, and short route for the synthesis of simplactones A ( 1 ) and B ( 2 ) was achieved from a synthetically prepared chiral auxiliary, i.e., the Oppolzer camphor‐derived sultam 4 , and (4‐methoxybenzyl)‐protected 3‐hydroxypropanal, in 52 and 48% overall yield, respectively, and with high diastereoselectivity (Schemes 2 and 3).     

Machine learning-based modeling to predict inhibitors of acetylcholinesterase

Molecular Diversity - Acetylcholinesterase enzyme is responsible for the degradation of acetylcholine and is an important drug target for the treatment of Alzheimer’s disease. When this...     

Solvent dependent growth of fibrous and non-fibrous nanocrystalline thin films of ZnO

Zinc oxide thin films were prepared from three different solvents using the sol–gel technique. Zinc acetate was used as the source of Zn, and the solvents ethanol, 2-methoxy ethanol and ethylene glycol were used to prepare the sols. ZnO thin films were deposited on glass microslides by pre-heating dip coated sol layers, following which they were finally annealed at 450 °C for half an hour. The films were characterized using structural, morphological and optical techniques. XRD studies show that the films grown from all the three solvents were single phase, highly oriented (along the c axis) ZnO having the wurzite structure. Optical transmission and photoluminescence spectra confirm the good quality of the ZnO films. SEM and AFM images show that the surfaces of the ZnO films, obtained using the first two (more volatile) solvents, consist of striations or ridges of height around 100–400 nm and are made up of nanoparticles 20–40 nm in size. The surfaces of the films produced from the less volatile third solvent are however smooth and devoid of striations although they are also covered with nanoparticles.     

Natural organic acids promoted Beckmann rearrangement: Green and expeditious synthesis of amides under solvent-free conditions

Naturally occurring organic acids are reported to be highly efficient promoters of the Beckmann rearrangement. Citric, oxalic, tartaric, malic, succinic, malonic, and fumaric acids efficiently promote the Beckmann rearrangement under solvent-free conditions and thermal and microwave irradiation. Tartaric acid was found to be the best promoter of the Beckmann rearrangement under conventional conditions as well as under microwave irradiation. Compared with conventional heating, microwave irradiation provides higher reaction rate and slightly higher yields.     

Heck Reaction: Stereo Selective Synthesis of Trisubstituted Olefins: Useful Intermediates for Anthraquinone Carboxylic Acid Derivatives

Palladium catalyzed arylation of dialkyl itaconate in presence of Pd(OAc)2/PPh₃ as a catalyst, afforded trisubstituted olefins stereo selectively. These alkenes are useful intermediates for the synthesis of anthraquinone carboxylic acid derivatives. A new coumarin is also synthesized using this protocol.     

Impossibility of a continuous phase convention for polarised light

The possibility of extending the well known Poincare sphere representation of polarised light to include phase is considered. Any attempt to define the zero of phase for each vibration represented on the Poincare sphere runs into discontinuities at at least one point. These are shown to be inevitable using a topological argument.