Sunny, Kuriakose; Dr.Abdul Rasheed, T M(Cochin University Of Science And Technology, October 7, 2003)
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Abstract:
Vibrational overtone spectroscopy of molecules containing X-H oscillators
(X = C, N, O...) has become an effective tool for the study of molecular structure,
dynamics, inter and intramolecular interactions, conformational aspects and
substituent effects in aliphatic and aromatic compounds. In the present work, the author studied the NIR overtone spectra of some liquid phase organic compounds. The analysis of the CH, NH and OH overtones yielded important structural
information about these systems. In an attempt to get information on electronic
energy levels, we studied the pulsed Nd:YAG laser induced fluorescence spectra
of certain organic compounds. The pulsed laser Raman spectra of some organic
compounds are also studied. The novel high resolution technique of near infrared
tunable diode laser absorption spectroscopy (TDLAS) is used to record the
rotational structure of the second OH overtone spectrum of 2-propanol. The
spectral features corresponding to the different molecular conformations could be
identified from the high resolution spectrum.
The whole work described in this thesis is divided into five chapters.
Description:
Department of Physics
Cochin University of Science and Technology
Sudha Kartha, C; Dr.Sathianandan, K(Cochin University of Science and Technology, February , 1984)
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Abstract:
The present study is mainly concéntrated on the visible
fluorescence of Ho3+ ,nd 3+ and Er 3+rare earths in
alkaline earth fluoride hosts(caF2,srF2,BaF2)
using a nitrogen laser excitation. A nitrogen laser was fabricated and its parametric studies were first carried out.
Description:
Department of Physics, Cochin University of Science and Technology
Paulraj,M; Dr.Vijayakumar, K P(Department of Physics, Faculty of Science, December , 2004)
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Abstract:
Materials and equipment which fail to achieve the design requirements or projected life due to undetected defects may require expensive repair or early replacement. Such defects may also be the cause of unsafe conditions or catastrophic unexpected failure, and will lead to loss of revenue due to plant shutdown. Non-Destructive Evaluation (NDE) / Non Destructive Testing (NDT) is used for the examination of materials and components without changing or destroying their usefulness. NDT can be applied to each stage of a system’s construction, to monitor the integrity of the system or structure throughout its life.
Poornima,N; Dr.Sudha Kartha,C(Cochin University Of Science And Technology, November , 2013)
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Abstract:
Photoluminescence (PL) spectroscopy is an optical technique that has
emerged successful in the field of semiconductor material and device
characterization. This technique is quite a powerful one which gives idea about
the defect levels in a material, the band gap of the material, composition as well
as material quality. Over the recent years it has received an elevation as a
mainstream characterization technique.
This thesis is an attempt to characterize each individual layer used in a thin
film solar cell with special focus on the electrical properties. This will be highly
beneficial from the lab as well as industrial point of view because electrical
measurements generally are contact mode measurements which tend to damage
the surface. As far as a thin film solar cell is concerned, the constituent layers are
the transparent conducting oxide (TCO), absorber layer, buffer layer and top
electrode contact. Each layer has a specific role to play and the performance of a
solar cell is decided and limited by the quality of each individual layer. Various
aspects of PL spectroscopy have been employed for studying compound
semiconductor thin films [deposited using chemical spray pyrolysis (CSP)]
proposed for solar cell application. This thesis has been structured in to seven
chapters
Description:
Applied Optics Division,
Department of Physics,
Cochin University of Science and Technology
Elizabeth, C V; Dr. Sreekumar, K(Cochin University of Science and Technology, September 29, 2010)
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Abstract:
Present thesis has discussed the design and synthesis of polymers suitable for nonlinear optics. Most of the molecules that were studied have shown good nonlinear optical activity. The second order nonlinear optical activity of the polymers was measured experimentally by Kurtz and Perry powder technique. The thesis comprises of eight chapters.The theory of NLO phenomenon and a review about the various nonlinear optical polymers has been discussed in chapter 1. The review has provided a survey of NLO active polymeric materials with a general introduction, which included the principles and the origin of nonlinear optics, and has given emphasis to polymeric materials for nonlinear optics, including guest-host systems, side chain polymers, main chain polymers, crosslinked polymers, chiral polymers etc.Chapter 2 has discussed the stability of the metal incorporated tetrapyrrole molecules, porphyrin, chlorin and bacteriochlorin.Chapter 3 has provided the NLO properties of certain organic molecules by computational tools. The chapter is divided into four parts. The first part has described the nonlinear optical properties of chromophore (D-n-A) and bichromophore (D-n-A-A-n-D) systems, which were separated by methylene spacer, by making use of DPT and semiempirical calculations.Chapter 4: A series of polyurethanes was prepared from cardanol, a renewable resource and a waste of the cashew industry by previously designed bifunctional and multifunctional polymers using quantum theoretical approach.Chapter 5: A series of chiral polyurethanes with main chain bis azo diol groups in the polymer backbone was designed and NLO activity was predicted by ZlNDO/ CV methods.In Chapter 7, polyurethanes were first designed by computational methods and the NLO properties were predicted by correction vector method. The designed bifunctional and multifunctional polyurethanes were synthesized by varying the chiral-achiral diol compositions
Description:
Department of Applied Chemistry, Cochin University of Science and Technology
Daly, Davis; Dr. Sreekumar, K(Cochin University Of Science And Technology, September 12, 2005)
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Abstract:
The present work emphasizes the use of chirality as an efficient tool to synthesize
new types of second order nonlinear materials. Second harmonic generation efficiency
(SHG) is used as a measure of second order nonlinear response. Nonlinear optical
properties of polymers have been studied theoretically and experimentally. Polymers
were designed theoretically by ab initio and semiempirical calculations. All the
polymeric systems have been synthesized by condensation polymerization. Second
harmonic generation efficiency of the synthesized systems has been measured
experimentally by Kurtz and Perry powder method
Description:
Department of Applied Chemistry, Cochin University of Science and
Technology
Ansa Alphonsa, Antony; Dr.Sankaran, P G(Cochin University of Science and Technology, September 1, 2005)
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Abstract:
So far, in the bivariate set up, the analysis of lifetime (failure time) data with
multiple causes of failure is done by treating each cause of failure separately. with
failures from other causes considered as independent censoring. This approach is
unrealistic in many situations. For example, in the analysis of mortality data on
married couples one would be interested to compare the hazards for the same cause
of death as well as to check whether death due to one cause is more important for the
partners’ risk of death from other causes. In reliability analysis. one often has
systems with more than one component and many systems. subsystems and
components have more than one cause of failure. Design of high-reliability systems
generally requires that the individual system components have extremely high
reliability even after long periods of time. Knowledge of the failure behaviour of a
component can lead to savings in its cost of production and maintenance and. in
some cases, to the preservation of human life. For the purpose of improving
reliability. it is necessary to identify the cause of failure down to the component
level. By treating each cause of failure separately with failures from other causes
considered as independent censoring, the analysis of lifetime data would be
incomplete. Motivated by this. we introduce a new approach for the analysis of
bivariate competing risk data using the bivariate vector hazard rate of Johnson and
Kotz (1975).
Description:
Department of Statistics, Cochin University of Science and Technology
Sajitha, T S; Dr.Unnikrishnan, P A(Cochin University of Science And Technology, February 19, 2014)
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Abstract:
Burgess reagent first prepared by E. M. Burgess in 1968, is a mild
and selective dehydrating agent for secondary and tertiary alcohols and
due to the amphipolar nature it is gainfully employed in a number of
creative synthetic ventures. A close examination of the structure of
Burgess reagent reveals that it can act as a 1,2-dipole. To the best of our
knowledge, no attempts have been made to tap full synthetic potential of
the amphipolar nature of this reagent and no reports on 1,3-dipolar
addition to a σ-bond in acyclic systems are available in literature. In this
context, we propose to unravel novel applications of Burgess reagent
based on its amphipolar nature.
Rich and multifaceted chemistry of nitrones form the basis of
many successful chemical transformations used in attractive synthetic
strategies. For the last 50 years special attention has been given to
nitrones due to their successful application as building blocks in the
synthesis of various natural and biologically active compounds. Our
interest in nitrones stems out of its unique character: i.e. it is a 1,3-dipole
exhibiting distinct nucleophilic activity.
We reasoned that 1,3-dipole possessing significant nucleophilicity
should react with amphipolar Burgess reagent with elimination of
triethylamine to give the corresponding five-membered ring product by
formal dipolar addition to a σ bond. To test this hypothesis we studied
the reaction of nitrones with Burgess reagent. This thesis reveals our
attempts to explore the [3+2] annulation reaction of nitrones with
Burgess reagent which was found to be followed by a rearrangementinvolving C-to-N aryl migration, ultimately resulting in diarylamines and
carbamates.
We have also examined the reaction of cyanuric chloride with
nitrones in DMF with a view to exploit the nucleophilicty of nitrones and
to unravel the migratory aptitude, if any, observed in this reaction
Description:
Department
of Applied Chemistry, Cochin University of Science and Technology
Anuja, E V; Girish Kumar, K(Cochin University Of Science And Technology, August 6, 2015)
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Abstract:
There is an enormous demand for chemical sensors in many areas and disciplines including chemistry, biology, clinical analysis, environmental science. Chemical sensing refers to the continuous monitoring of the presence of chemical species and is a rapidly developing field of science and technology. They are analytical devices which transform chemical information generating from a reaction of the analyte into an measurable signal. Due to their high selectivity, sensitivity, fast response and low cost, electrochemical and fluorescent sensors have attracted great interest among the researchers in various fields.
Development of four electrochemical sensors and three fluorescent sensors for food additives and neurotransmitters are presented in the thesis. Based on the excellent properties of multi walled carbon nanotube (MWCNT), poly (L-cysteine) and gold nanoparticles (AuNP) four voltammetric sensors were developed for various food additives like propyl gallate, allura red and sunset yellow. Nanosized fluorescent probes including gold nanoclusters (AuNCs) and CdS quantum dots (QDs) were used for the fluorescent sensing of butylated hydroxyanisole, dopamine and norepinephrine.
A total of seven sensors including four electrochemical sensors and three fluorescence sensors have been developed for food additives and neurotransmitters.
Anu Jose; G. Vijay Nair(Cochin University of Science and Technology, August 21, 2014)
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Abstract:
Carbon-carbon and carbon-heteroatom bond formations constitute the
central events in organic synthesis. In view of this, much of the research in
organic synthesis has been focused on devising novel and efficient methods for
such bond constructions. In general, polar, pericyclic and radical methodologies
are employed for this purpose. The polar and radical reactions proceed via
reactive intermediates such as carbanions, enols/enolates, enamines, carbocations,
radical cations, radical anions, carbenes, zwitterions etc. In recent years, there has
been enormous interest in the chemistry of zwitterionic species largely from the
standpoint of their applications in multicomponent reactions (MCRs) and
organocatalytic reactions. Zwitterions formed by the addition of nucleophiles to
electrophilic π-systems such as acetylenic esters and azoesters have been the
subject of extensive investigations; their synthetic utility, however, remained
largely unexplored. Investigations in a number of laboratories, including our own,
have shown that zwitterions of the type mentioned above on reaction with
electrophiles give rise to carbo- and heterocyclic products by 1,3- or 1,4-dipolar
cycloadditions. Recently, allenoates, another class of active π-systems were
introduced to this field. Against this background, a systematic investigation of the
reactions of various zwitterions derived from allenoates with different
electrophiles especially 1,2-diones, were carried out. The results of these studies
are embodied in the thesis entitled “Novel Synthesis of Carbocycles and
Heterocycles Employing Zwitterions Derived from Allenic Esters”.
Rakesh N.; Dr. Prathapan S.(Cochin University of Science and Technology, December 13, 2015)
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Abstract:
Nitrones or azomethine-N-oxides are important precursors for the synthesis of several heterocyclic systems. They belong to the allyl anion type 1,3-dipoles and possess unique structural features which make them extraordinarily useful synthons. They behave as 1,3-dipoles in 1,3-dipolar cycloaddition reactions and as electrophiles in reactions with organometallic reagents. These are the two basic reactions given by nitrones. Nitrones also act as ‘spin traps’ in which they react with short-lived radicals to furnish stable nitroxide radicals which can be detected and identified by electron paramagnetic resonance (EPR) spectroscopy. Recently SmI2 catalysed reductive cross-coupling reactions of nitrones have gained significant interest in which the reactions are initiated by single electron transfer (SET) to nitrones. Apart from these reactions, nitrones are also known to participate in reactions which are initiated by the nucleophilic attack of nitrone-oxygen. In our group, we have also explored the nucleophilic character of nitrones through various reactions. The results obtained enabled us to develop a novel two-step one-pot strategy for quinolines and indoles - the heterocycles renowned for their pharmacological applications, from nitrones and electron deficient acetylenes. Using dibenzoylacetylene and phenylbenzoylacetylene as dipolarophiles, we could introduce a desired functional group at a predetermined position of the quinolines or indoles to be synthesised. In this context, the thesis entitled “NUCLEOPHILIC ADDITION OF NITRONES TO ELECTRON DEFICIENT ACETYLENES AND RELATED STUDIES” portrays our attempt to expand the scope of our
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novel synthetic protocol using ester functionalised acetylenes: dimethyl acetylenedicarboxylate (DMAD) and methyl propiolate.
The thesis is organised in to five chapters. The first chapter briefly describes the different classes of reactions that nitrone functionality can tolerate. The research problem is defined at the end of this chapter. The second chapter describes the synthesis of different nitrones used for the present study. The optimisation and expansion of scope of the novel strategy towards quinoline synthesis is discussed in the third chapter. The fourth chapter portrays the synthesis of indole-3-carboxylates using the novel strategy. In the fifth chapter, the reaction of N-(2,6-dimethylphenyl) and N-(2,4,6-trimethylphenyl)nitrones are discussed. Here we also discuss the mechanistic reinvestigation of Baldwin’s proposal in the isoxazoline-oxazoline rearrangement. The major outcome of the work is given at the end of the thesis.
The structural formulae, schemes, tables and figures are numbered chapter-wise since each chapter of the thesis is organized as an independent unit. All new compounds (except two compounds reported in fourth chapter) are fully characterised on the basis of spectral and analytical data and single crystal X-ray analysis on representative examples. Relevant references are included at the end of individual chapters.