Chemistry

<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

Shiv Nadar University

This article describes synthesis, characterization and properties of blends of benzoxazine (Bz) monomers, i.e., m-alkylphenyl-3,4-dihydro-2H-benzoxazine (Bz-C), 6,6′-(propane-2,2-diyl)bis(3-phenyl-3,4-dihydro-2H-benzoxazine (Bz-A) and 3-phenyl-3,4-dihydro-2H-benzoxazine-p-carboxylic acid (Bz-pA). Binary blends of Bz-C with Bz-pA, and Bz-A with Bz-pA were prepared by first synthesizing Bz-C or Bz-A followed by the addition of all the ingredients of Bz-pA. In a similar manner, ternary blends of Bz-C, Bz-A and Bz-pA were prepared by first synthesizing Bz-C and subsequent addition of all the ingredients of Bz-A and Bz-pA in one pot. The Bz monomer blends were characterized by 1H-NMR, FTIR spectroscopy, and differential scanning calorimetry. The temperature of onset of curing (T o), due to ring-opening polymerization of Bz was found to decrease significantly by incorporation of carboxyl groups (Bz-pA) showing thereby the catalytic effect of acid functionality. Bz polymers showed good thermal stability and incorporation of Bz-pA in blends resulted in a highly cross-linked network. The interlaminar shear strength of glass fabric reinforced composites and the lap shear strength of metal-metal joints using these resin blends was also investigated. © 2012 Akadémiai Kiadó, Budapest, Hungary.

(SoNS) School of Natural Sciences

World University root node

Journal of Thermal Analysis and Calorimetry

Blends of benzoxazine monomers: Effect of structure and composition on polymer properties

In the area of catalysis, nanoparticles and enzymes are two of the most important systems. By amalgamating the two, we present here proof of the concept that it is possible to prepare a multifunctional catalyst that can carry out a "relay" reaction. The catalyst consists of a surface bound enzyme on a metalcore-silicashell nanoparticle architecture. Here the enzyme catalyzes the 1st reaction and the metal nanoparticles act as a catalyst for the 2nd reaction of the product from the 1st reaction. In particular, we have studied the catalytic activity of glucosidase grafted Au@mSiO2 on 4-nitrophenyl-β-glucopyranoside, where glucosidase will catalyse the 1st step to generate 4-nitrophenol, which acts as a substrate for the next reduction step which is catalysed by the Au nanoparticles present inside the mesoporous silica shell. © 2013 The Royal Society of Chemistry.

Fulltext

RSC Advances

Development of a multifunctional catalyst for a "relay" reaction

Copper(II) complexes [Cu(Fc-aa)(cur)] (1-3) of curcumin (Hcur) and N-ferrocenylmethyl-l-amino acids (Fc-aa), viz., ferrocenylmethyl-l-tyrosine (Fc-TyrH), ferrocenylmethyl-l-tryptophan (Fc-TrpH) and ferrocenylmethyl-l- methionine (Fc-MetH), were prepared and characterized. The DNA photocleavage activity, photocytotoxicity and cellular localization in HeLa and MCF-7 cancer cells of these complexes were studied. Acetylacetonate (acac) complexes [Cu(Fc-aa)(acac)] (4-6) were prepared and used as controls. The chemical nuclease inactive complexes showed efficient pUC19 DNA cleavage activity in visible light. Complexes 1-3 showed high photocytotoxicity with low dark toxicity thus giving remarkable photodynamic effect. FACScan analysis showed apoptosis of the cancer cells. Fluorescence microscopic studies revealed primarily cytosolic localization of the complexes. {\textcopyright} 2013 Elsevier Masson SAS. All rights reserved.

European Journal of Medicinal Chemistry

Photocytotoxicity of copper(II) complexes of curcumin and N-ferrocenylmethyl-l-amino acids

The intramolecular Dötz benzannulation with alkyne-tethered aryloxy Fischer carbenes has been applied to synthesize a nine membered diaryl ether linked macrocyclic library. Insilico tools, that is, shape space analysis was used to assess the diversity of the library, and polar surface area (PSA) of the compounds were deduced to understand the range of their surface electrostatic potential. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Asian Journal of Organic Chemistry

Diversity Oriented Synthesis of Macrocyclic Diaryl Ethers by Dötz Benzannulation

Macroscopic properties of biomolecular systems are a straightforward consequence of time dependent microscopic interactions. Molecular Dynamics (MD) Simulations provide a time dependent microscopic properties of biomolecules, which could not be explained by experimental methods like X-ray crystallography. These specifications enable MD simulations as most widely used computational techniques for the study of dynamical properties of proteins, DNAs and other bio-macromolecules. In the present chapter, we focus the scopes, applicability and major case studies of MD simulations. The chapter also provides some lucid discussions about the pros and cons of free energy pathways like MM-PB (GB)/SA, LIE and other alchemical methods which are frequently used to study the binding mode of several biomolecular complexes. © 2013 by Apple Academic Press, Inc.

Nanoscience and Computational Chemistry: Research Progress

Molecular dynamics simulations: Applicability and scopes in computational biochemistry

The activity of gelatin and collagen proteins towards C-C bond formation via Henry (nitroaldol) reaction between aldehydes and nitroalkanes is demonstrated for the first time. Among other variables, protein source, physical state and chemical modification influence product yield and kinetics, affording the nitroaldol products in both aqueous and organic media under mild conditions. Significantly, the scale-up of the process between 4-nitrobenzaldehyde and nitromethane is successfully achieved at 1 g scale and in good yield. A comparative kinetic study with other biocatalysts shows an increase of the first-order rate constant in the order chitosan < gelatin < bovine serum albumin (BSA) < collagen. The results of this study indicate that simple edible gelatin can promote C-C bond forming reactions under physiological conditions, which may have important implications from a metabolic perspective. © 2013 Kühbeck et al; licensee Beilstein-Institut.

Beilstein Journal of Organic Chemistry

C-C bond formation catalyzed by natural gelatin and collagen proteins

An enhanced dielectric permittivity of polyethylene and related polymers, while not overly sacrificing their excellent insulating properties, is highly desirable for various electrical energy storage applications. In this computational study, we use density functional theory (DFT) in combination with modified group additivity based high throughput techniques to identify promising chemical motifs that can increase the dielectric permittivity of polyethylene. We consider isolated polyethylene chains and allow the CH2 units in the backbone to be replaced by a number of Group IV halides (viz., SiF 2, SiCl2, GeF2, GeCl2, SnF 2, or SnCl2 units) in a systematic, progressive, and exhaustive manner. The dielectric permittivity of the chemically modified polyethylene chains is determined by employing DFT computations in combination with the effective medium theory for a limited set of compositions and configurations. The underlying chemical trends in the DFT data are first rationalized in terms of various tabulated atomic properties of the constituent atoms. Next, by parametrizing a modified group contribution expansion using the DFT data set, we are able to predict the dielectric permittivity and bandgap of nearly 30 000 systems spanning a much larger part of the configurational and compositional space. Promising motifs which lead to simultaneously large dielectric constant and band gap in the modified polyethylene chains have been identified. Our theoretical work is expected to serve as a possible motivation for future experimental efforts. © 2013 American Chemical Society.

Journal of Chemical Information and Modeling

New group IV chemical motifs for improved dielectric permittivity of polyethylene

The first high-resolution neutron protein structure of perdeuterated rubredoxin from Pyrococcus furiosus (PfRd) determined using the new IMAGINE macromolecular neutron crystallography instrument at the Oak Ridge National Laboratory is reported. Neutron diffraction data extending to 1.6514;Å resolution were collected from a relatively small 0.714;mm3 PfRd crystal using 2.514;d (6014;h) of beam time. The refined structure contains 371 out of 391, or 95%, of the D atoms of the protein and 58 solvent molecules. The IMAGINE instrument is designed to provide neutron data at or near atomic resolution (1.514;Å) from crystals with volume &lt;1.014;mm3 and with unit-cell edges &lt;10014;Å. Beamline features include novel elliptical focusing mirrors that deliver neutrons into a 2.0 × 3.214;mm focal spot at the sample position with full-width vertical and horizontal divergences of 0.5 and 0.6°, respectively. Variable short- and long-wavelength cutoff optics provide automated exchange between multiple-wavelength configurations (λmin = 2.0, 2.8, 3.314;Å to λmax = 3.0, 4.0, 4.5, ∼2014;Å). These optics produce a more than 20-fold increase in the flux density at the sample and should help to enable more routine collection of high-resolution data from submillimetre-cubed crystals. Notably, the crystal used to collect these PfRd data was 5-10 times smaller than those previously reported. © 2013 International Union of Crystallography Printed in Singapore - all rights reserved. © 2013.

Acta Crystallographica Section D: Biological Crystallography

The IMAGINE instrument: First neutron protein structure and new capabilities for neutron macromolecular crystallography

An electron rich porous metal–organic framework (MOF) has been synthesized, which acts as an effective heterogeneous catalyst for Diels–Alder reactions through encapsulation of the reactants in confined nano-channels of the framework. {\textcopyright} 2013 The Royal Society of Chemistry.

Chemical Communications

An electron rich porous extended framework as a heterogeneous catalyst for diels–alder reactions

Two new anthracene-functionalized fluorescent tris-imidazolium salts have been synthesized, characterized and proven to be selective sensors for picric acid, which is a common constituent of many powerful explosives. Theoretical studies revealed an unusual ground-state electron transfer from picrate anion to the sensor molecules. {\textcopyright} 2013 American Chemical Society.