http://hdl.handle.net/123456789/1052 Fri, 12 May 2023 07:57:23 GMT 2023-05-12T07:57:23Z http://hdl.handle.net/123456789/1337 Title: Metal Organic Coordination Networks Comprised of Divalent Metal Centers and Multiatom Carboxylate Linkers Authors: Khullar, S.; Mandal, S.K. Abstract: In the past fifteen years a large number of metal organic coordination networks (MOCNs) has been designed and developed for their diverse structural aesthetics and for a variety of potential applications in catalysis, separation, sensors, gas storage, luminescent materials, ion exchange, magnetism, etc. Formation of infinite one-, two-, and three dimensional (1D, 2D, and 3D) MOCNs requires highly organized structures held together through various interactions, such as metal-donor atom coordinate bonds, strong and/or weak hydrogen bonds, pi-pi stacking of aromatic moieties, C-H…O interactions, etc. This thesis focuses on the strategic design and development of MOCNs through reproducible synthesis under ambient as well as hydrothermal conditions. Over one hundred new MOCNs comprised of divalent transition metal ions, polydentate ancillary ligands and multiatom carboxylate linkers have been synthesized in good to high yields. For making these MOCNs several ancillary ligands (with improved yields and purity) have also been synthesized and characterized. Through systematic studies, such MOCNs with well-defined structures and tunable metrics are obtained. These have diverse structures and topologies, are chemically and thermally stable, have a variety of functions. These are characterized by elemental analysis, FT-IR, Raman and UV-Vis spectroscopy, single crystal and powder X-ray diffraction, and ESI-MS analysis as well as are studied for their redox behavior by cyclic voltammetry, morphology by scanning electron microscopy and thermal properties by thermogravimetric analysis and differential scanning calorimetry. Their photoluminescent properties are established by fluorescence spectroscopy in the solid state. Several of these MOCNs are found to be porous (termed as Metal Organic Frameworks) and have been tested for their water and gas adsorption/desorption abilities. Thu, 03 Jul 2014 00:00:00 GMT http://hdl.handle.net/123456789/1337 2014-07-03T00:00:00Z http://hdl.handle.net/123456789/1336 Title: Description of Radio-Frequency (RF) Pulses in Quadrupolar Nuclei Authors: R, Venkata SubbaRao; Ramachandran, Ramesh Abstract: With the development of technology and improved understanding of nuclear spin-spin interactions and their behavior in static/oscillating magnetic fields, NMR spectroscopy has emerged as a powerful tool for characterizing molecular structure in wide range of systems of chemical, physical and biological relevance. Here in this thesis, employing the concept of effective Hamiltonians, an analytic theory is introduced to describe transitions in a multi-level system in nuclear magnetic resonance (NMR) spectroscopy. Specifically, the discussion is centered towards the treatment of selective and non-selective excitations in static single-crystal and magic angle spinning (MAS) powder sample in quadrupolar spin (I > 1/2) systems. Employing the spherical tensor formalism, effective radio-frequency (RF) Hamiltonians are proposed for describing transitions in I=1, 3/2 and 5/2. The optimum conditions desired for selective excitation in a multi-level system are derived pedagogically from first principles and presented through analytic expressions. As an extension of this approach, multi-quantum (MQ) excitation in quadrupolar systems is discussed. Since MQ NMR spectroscopy of quadrupolar nuclei forms the basis for structural characterization of inorganic solids and clusters, we believe that the analytic theory presented herein would be beneficial both in the understanding and design of MQ NMR experiments. Wed, 19 Jul 2017 00:00:00 GMT http://hdl.handle.net/123456789/1336 2017-07-19T00:00:00Z http://hdl.handle.net/123456789/1335 Title: Studies on Larval Hematopoiesis in Drosophila: the Microenvironment and its Hematopoietic Stem Cells Authors: Dey, Nidhi Sharma; Mandal, L. Abstract: There is no abstract Wed, 19 Jul 2017 00:00:00 GMT http://hdl.handle.net/123456789/1335 2017-07-19T00:00:00Z http://hdl.handle.net/123456789/1334 Title: Characterization of Helicobacter Pylori TlyA as a Membrane-damaging Cytotoxic Protein with Amyloidogenic Property Authors: Lata, K.; Chattopadhyay, K. Abstract: Abstract not available Sun, 04 Sep 2016 00:00:00 GMT http://hdl.handle.net/123456789/1334 2016-09-04T00:00:00Z