ETD at Indian Institute of Science
Repository of Theses and Dissertations of Indian Institute of Science, Bangalore, India. The repository has been developed to capture, disseminate and preserve research theses of Indian Institute of Science.
Inorganic and Physical Chemistry (ipc)
Mostrando recursos 1 - 20 de 99
Rotational Specroscopic And Theoretical Investigations Of Non-conventional Hydrogen Bonds - Aiswarya Lakshmi, P
The nature of interactions within a molecule, i.e. chemical bonding, is well understood today. However, our understanding about intermolecular interactions, which has great relevance in nature, is still evolving. Historically there are two types of intermolecular interactions, van der Waals interaction and hydrogen bonding. However, there has been an upsurge of interest in the halogen bonding and lithium bonding during the last decade. The main emphasis of our research is to understand these interactions in detail, in particular non-conventional hydrogen bond acceptors. In this work, weakly bound complexes are studied using Pulsed Nozzle Fourier Transform Microwave Spectrometer, which has been...
Probing The Equilibrium Geometry Of Weakly Interacting Systems In Solution By Hyper-Rayleigh Scattering - Pandey, Ravindra
Under the electric dipole approximation, second harmonic of the incident light is scattered by a collection of randomly oriented molecular dipoles in solution due to instantaneous orientational fluctuation which is directional. If two such dipoles are correlated in space through intermolecular or other interactions, the intensity of the second harmonic scattered light (SHSL) will be related to the extent of such interactions. If two dipoles are arranged in a particular geometry by design, the geometry will determine the intensity of the SHSL. If a molecule has no dipole moment, the intensity of the SHSL will be less and is only...
Understanding Solvent Effect On Triplet State Structure Of Thioxanthone And Its Derivatives Using Time-Resolved Resonance Raman Spectroscopy - Pandey, Rishikesh
It has long been recognized that course and efficiency of a chemical reaction is largely mediated by the short-lived transient species (excited state or radicals) which are formed as reactive intermediates during a chemical reaction. Subtle changes not only in the bonding and electronic distributions but also in the conformations and geometries of these intermediates have a dramatic influence on the reactivity. A detailed understanding of the structural and dynamical aspects of electronic excited states is therefore essential towards unraveling photoinduced natural processes and for designing novel photonic materials. Time-resolved techniques have been widely used to study the transient species...
Conformational Reorganization Of Hyperbranched And Linear Polymers And Functionalized Porous Polymer Films - Samuel, Ashok Zachariah
The main focus of the research work presented in the thesis is the understanding of structural and conformational reorganizations in hyperbranched and linear polymers. The thesis includes three different investigations: a) the design, synthesis, conformational reorganizations and self-assembly of hyperbranched polymers (HBPs), b) the Raman spectroscopic studies of the melting of polyethylene glycol (PEG), and c) the preparation of functionalized porous polymer films.
HBPs are structurally imperfect analogues of the defect-free branched polymers called dendrimers. Dendrimers prepared using a stepwise polymerization methodology will carry all the unreacted B groups at the periphery and therefore modification of these peripheral units with...
Theoretical Studies Of Electronic Excitation Energy Transfer Involving Some Nanomaterials - Swathi, R S
Electronic Excitation Energy Transfer is an important intermolecular photophysical process that can affect the excited state lifetime of a chromophore. A molecule in an electronically excited state can return to the ground state by radiative as well as non-radiative processes. During the excited state lifetime, if the chromophore (energy donor) finds a suitable species (energy acceptor) nearby with resonant energy levels, it can transfer the excitation energy to that species and return to the ground state. This process is called Electronic Excitation Energy Transfer. When the energy donor is fluorescent, the process is called Fluorescence Resonance Energy Transfer (FRET) ....
Titanium Nitride-Based Electrode Materials For Oxidation Of Small Molecules : Applications In Electrochemical Energy Systems - Musthafa, O T Muhammed
Synopsis of the thesis entitled “Titanium Nitride-Based Electrode Materials for Oxidation of Small Molecules: Applications in Electrochemical Energy Systems” submitted by Muhammed Musthafa O. T under the supervision of Prof. S. Sampath at the Department of Inorganic and Physical Chemistry of the Indian Institute of Science for the Ph.D degree in the faculty of science.
Fuel cells have been the focus of interest for many decades because of the ever increasing demands in energy. Towards this direction, there have been considerable efforts to find efficient electrocatalysts to oxidize small organic molecules (SOMs) such as methanol, ethanol, glycerol, hydrazine and borohydride...
Resonance Energy Transfer Using ZnO Nanocrystals And Magnetism In The Mixed Metal Layered Thiophosphates, Mn1-xFexPS3(0≤x≥1) - Rakshit, Sabyasachi
This thesis consists of two parts. The first part deals with the visible emission of ZnO Nanocrystals and its possible application in Resonance Energy Transfer (RET) studies. The second part of the thesis is on the magnetic properties of the layered transition metal Thiophosphates MPS3 (M = Mn, Fe), their solid solutions and intercalation compounds.
Recent advances in semiconductor nanocrystals or quantum dots (QDs) as inorganic fluorophores have pioneered a new direction in the fluorescent based techniques to investigate fundamental processes in lifesciences. Their broad absorption spectra with narrow, Size-tunable emissions with high quantum e±ciency and stability under relative harsh environments...
Graphite Oxide And Graphite Oxide-Based Composites : Physicochemical And Electrochemical Studies - Ramesha, G K
One of the major directions of research in the area of materials science is to impart multifunctionalities to materials. Carbon stands on the top of the list to provide various multifunctional materials. It exists in all dimensions, zero (fullerene), one (carbon nanotube, CNT), two (graphene) and three (graphite) dimensions are very well-known for their versatility in various studies. They are also used in various applications in nanoelectronics, polymer composites, hydrogen production and storage, intercalation materials, drug delivery, sensing, catalysis, photovoltaics etc. Electrical conductivity of carbon can be tuned from insulator (diamond) to semiconductor (graphene) to conductor (graphite) with varying band...
Self-Assembly Of Discrete Molecular Architectures : Design, Synthesis And Characterization - Ghosh, Sushobhan
Stepwise covalent synthesis of large molecules is often time consuming and laborious and thus generally ends in a low yield of the target product. It is also difficult to achieve a large desired product where the controlling force is a non-directional weak interaction. Instead, by utilizing stronger metal-ligand directional coordination bonding approach, one can easily prepare the desired large molecules using appropriate molecular units. Further attractive feature of this approach is the incorporation of functional groups into final structures to make the assemblies functional. It is found that symmetrical polypyridyl and rigid linkers have been used widely in the construction...
Thermal Decomposition Of Haloethanols And Ignition Of JP-10 - Chakravarty, Harish Kumar
In this thesis, the thermal decomposition investigation of haloethanols namely 2-chloroethanol and 2-bromoethanol are reported both experimental and theoretical. Computational calculation of enthalpy of formation haloethanols using isodesmic and atomization reactions has also been reported. Finally, the chemistry of JP-10 ignition has also been investigated using shock tube.
Chapter 1 gives a brief introduction to the experimental shock tube technique. Brief surveys of literature pertinent to haloethanols and JP-10 have also been discussed. The importance of thermal rate coefficient and detection techniques in shock tube chemistry is presented. Details of the theoretical methods used in the determination of thermal rate...
Chemistry Of Ferrocene Conjugates Showing DNA Cleavage And Photocytotoxic Activity - Maity, Basudev
Ferrocene is an important molecule in the field of chemical biology due to its stability, unique redox property and significant lipophilicity for better cellular delivery. The medicinal importance of ferrocene is well recognized after its successful incorporation into breast cancer drug tamoxifen and antimalarial drug chloroquin. Designing ferrocene conjugated transition metal complexes is an interesting area of research in the field of photodynamic therapy, a new modality of light activated cancer treatment. The objective of the present thesis work is to develop photoactive ferrocene conjugates showing DNA photocleavage and photocytotoxic activity.
We have synthesized the ferrocene conjugated imidazophenanthroline derivative which...
Controlling Conformation Of Macromolecules Using Non-Covalent Interaction And Micellization Behaviour Of Isomeric Phenyl Bearing Cationic Surfactants - De, Swati
This thesis contains investigations in two different areas, described under six chapters. Chapter 1 contains a broad introduction to the area of foldamers, while Chapters 2, 3, 4, and 5 deal with various novel classes of synthetic polymers which can form folded structures in solution utilizing different non-covalent interactions. Chapter 6 deals with a distinctly different topic, where the objective was to study the effect of phenyl ring location on the micellization properties of a series of isomeric cationic surfactants.
Synthetic polymers typically adopt a random coil conformation in solution, which is primarily an entropy driven process. So the generation...
Molecularly Imprinted Polymers Based On Fluorescent And Template Binding Cross-Linker - Chakraborty, Twarita
The synthesis of materials with molecular recognition properties has become a topic of great technological and scientific interest. Molecular imprinting is one of the most effective strategies in preparing highly selective synthetic receptors. The technique of molecular imprinting involves the copolymerization of functional and cross-linking monomers in the presence of a molecular template. Following polymerization and subsequent removal of the template, the molecularly imprinted polymer (MIP) retains a “molecular memory” of the template. During rebinding, the resultant polymer shows higher affinity and selectivity towards the molecular template when compared to other structural analogs. Ease of preparation and high thermal and...
Intercalation Of Alkyl Surfactants In Layered Double Hydroxides : The Anchored Bilayer In Dispersions And The Condensed Phase - Naik, Vikrant Vijay
Bilayers formed by molecules that possess long alkyl hydrophobic tails are ubiquitous in the natural world manifesting both in biological systems as well as in chemistry. The lipid bilayer is an integral feature of cell membranes of living systems with functions that are of critical importance to the life of the cell. Long chain amphiphilic surfactant molecules can be introduced within the interlamellar region of layered inorganic host lattices to form anchored alkyl chainbilayerswithinthegalleries.Theintercalatedbilayerbearsastriking resemblance to lipid bilayers. However, unlike lipid bilayers where individual molecules can undergo lateral diffusion and also flip-flop between layers the anchored bilayer is characterized by...
Polynuclear Coordination Assemblies : Synthesis, Crystal Structures And Magnetic Behavior - Sengupta, Oindrila
Construction of polynuclear metal assemblies from discrete 0D clusters to extend 3D networks, comprised of metal ions and bridging organic/inorganic ligands has attracted immense attention, owing to their intriguing network topologies and interesting properties. Proper ligand design and the appropriate choice of the metal center are of vital importance to the design of such polynuclear assemblies. One of the various attributes of polynuclear metal assemblies is magnetism. Magnetic materials can be constructed by incorporating magnetic moment carriers such as paramagnetic metals(V, Cr, Mn, Fe, Co, Ni, Cu) in presence of bridging ligands.
Though, one-atom oxo/hydroxo and two-atom cyanide bridges were...
Electrochemical Supercapacitor Investigations Of MnO2 And Mn(OH)2 - Nayak, Prasant Kumar
Electrical double-layer formed at the electrode/electrolyte interface in combination with electron-transfer reaction can lead to many important applications of electrochemistry, including energy storage devices, namely, batteries, fuel cells and electrochemical supercapacitors. Electrochemical supercapacitors are characterized by their higher power density as compared to batteries and higher energy density than the conventional electrostatic and electrolytic capacitors. Thus, supercapacitors are useful as auxiliary energy storage devices along with primary sources such as batteries or fuel cells for the purpose of power enhancement in short pulse applications. These are expected to be useful in hybrid devices together with batteries or fuel cells, in...
Theoretical Studies Of The Thermodynamics And Kinetics Of Selected Single-Molecule Systems - Chatterjee, Debarati
This thesis is a report of the work I have done over the last five years to study thermodynamic and kinetic aspects of single-molecule behavior in the condensed phase. It is concerned specifically with the development of analytically tractable models of various phenomena that have been observed in experiments on such single-molecule systems as colloids, double-stranded DNA, multi-unit proteins, and enzymes. In fluid environments, the energetics, spatial conformations, and chemical reactivity of these systems undergo fluctuations that can be characterized experimentally in terms of time correlation functions, survival probabilities, mean first passage times, and related statistical parameters. The thesis shows...
Studies On The Cobalt And Complexes Showing Anaerobic DNA Photocleavage Activity - Lahiri, Debojyoti
Photodynamic therapy (PDT) is a non-invasive treatment of cancer with an advantage of
having localized photo-activation of the drug at the targeted tumor cells leaving the healthy cells unaffected by the photo-toxicity of the PDT agent. Organic molecules and 4d/5d metal complexes have been extensively studied for their DNA cleavage activity and photo-cytotoxicity in UV and/or visible light. The photoactivity of the current PDT drugs is due to reactive singlet oxygen species. To address the hypoxic nature within neoplasia and to get a realistic scenario to build model and potent PDT agents, attempts have been made in this thesis work to...