Supersymmetric regulators and supercurrent anomalies

The supercurrent anomalies of the supercurrent $\text{S}$_μ of the supersymmetric Yang-Mills theory in Wess-Zumino gauge are computed using the supersymmetric dimensional regulator of Siegel. It is shown that $\text{γ}{}_{\mathrm{\mu }}\text{S}{}^{\mathrm{\mu }}\text{=0}$ and $\text{?}{}_{\mathrm{\mu }}\text{S}{}^{\mathrm{\mu }}\text{≠0}$ in agreement with an earlier calculation based on the Adler-Rosenberg method. The problem of exhibiting the chiral anomaly and a regulator for local supersymmetry suggests that the interpretation of dimensional reduction in component language is incomplete.     

Regioselective haloaromatization of 1,2-bis(ethynyl)benzene via halogen acids and PtCl2. Platinum-catalyzed 6-pi electrocyclization of 1,2-bis(1'-haloethenyl)benzene intermediates

[reaction: see text] Treatment of 1,2-bis(ethynyl)benzene (1) with aqueous HX (X = Br, I) in hot 3-pentanone (100-105 degrees C, 2 h) afforded 1,2-bis(1'-haloethenyl)benzene species 2-Br and 2-I in 98% and 95% yields, respectively. The hydrochlorination of endiyne 1 failed to proceed at elevated temperature but was implemented efficiently by PtCl2 (5 mol %) in hot 3-pentanone (100 degrees C, 2 h) to give 1,2-bis(1'-chloroethenyl)benzene 2-Cl in 80% yield. In the presence of PtCl2 (5 mol %), these halides 2-Cl,2-Br, and 2-I were subsequently converted to 1-halonaphthalenes 3-Cl, 3-Br, and 3-I in the mother solution via sequential 6-pi electrocyclization and dehalogenation reactions. PtCl2 (5 mol %) also effected direct haloaromatization of endiyne 1 with HX (X = Cl, Br, I) and gave 1-halonaphthalenes 3-Cl, 3-Br, and 3-I in 64-71% yields. This investigation reports the scope and the regioselectivity of haloaromatization of various enediynes catalyzed by PtCl2.     

First snapshot of a nonpolymeric hydrogelator interacting with its gelling solvents

A pyridyl urea based low molecular weight supramolecular hydrogelator has been synthesized; crystallized from its gelling solvents, the single crystal structure of the gelator molecule interacting with its gelling solvents reported herein is the first example in the literature.     

Organic crystals absorb hydrogen gas under mild conditions

We have studied the hydrogen sorption on three well-known organic hosts that possess vacant lattice voids large enough to accommodate H2 molecules.     

Non-stoichiometry induced by differential oxygen/lone pair occupation in chiral bicyclic 1,1'-binaphthoxy cyclodiphosphazanes

Non-stoichiometry and isostructurality in a set of chiral phosphorus compounds as a result of lone pair/oxygen exchange, substantiated by the combined use of 31P NMR spectroscopy and X-ray crystallography, is described.     

Role of aspartic acid in collagen structure and stability: A molecular dynamics investigation

A molecular dynamics (MD) simulation study has been carried out to understand the stability of the triple helical collagen models. The calculations show that the presence of the aspartic acid residue in different positions leads to the local variation in the structure. Analyses of root-mean-square deviation (RMSD), radial distribution function (RDF), puckering effect, dihedral angle variation, hydrogen bond (H-bond), and conformational changes during molecular dynamics simulation reveal that the local perturbation in the sequences, increase in chain flexibility due to removal of five membered rings in the collagen by aspartic acid, change of intermolecular H-bonding pattern, and differences in the association of water are mainly influencing the nature of stabilization of collagen by aspartic acid.     

Recent Development on Spectroscopic Methods for Chiral Analysis of Enantiomeric Compounds

Abstract

Chirality has become a central theme in scientific research and is an important task in the field of analytical chemistry. In the past few decades, demand for chiral recognition and separation has increased due to the importance of chirality in many fields such as pharmaceutics, chemical industry, agriculture, and biological and clinical analysis. A survey of the literature suggests that different spectroscopic methods are applied to achieve the analysis of chiral enantiomeric compounds. This article is intended to focus on chiral analysis and affords a brief overview on chiral analysis of enantiomeric compounds using different spectroscopic methods, such as fluorescence spectroscopy, mass spectrometry, and nuclear magnetic resonance spectroscopy. In this review, primarily the intensive studies of how chiral recognition is achieved and an updated view of the different strategies used up to recognize the chirality of enantiomeric compounds are discussed.