Seven bis(ligand) Co(III) complexes {[CoL21] NO3 · H2 O (1), [CoL21] Cl · 2 H2 O (2),[CoL21] ClO4 (3), [CoL22] NO3 (4), [CoL22] Cl · 2 H2 O (5), [CoL23] Br · 2 H2 O (6), [CoL23] ClO4 · H2 O (7)} of three thiosemicarbazone ligands {pyridine-2-carbaldehyde-N(4)-p-methoxyphenyl thiosemicarbazone [HL1], pyridine-2-carbaldehyde-N(4)-2-phenylethyl thiosemicarbazone [HL2] and pyridine-2-carbaldehyde-N(4)-(methyl),N(4)-(phenyl) thiosemicarbazone [HL3]} were synthesized and physico-chemically characterized. All complexes are assigned octahedral geometries on the basis of spectral studies. The ligands deprotonate and coordinate by means of pyridine nitrogen, azomethine nitrogen, and thiolate sulfur atoms. The single crystal X-ray structures of HL3 and two nitrate compounds are discussed. The structural studies corroborate the spectral characterization.
Junaid, Bushiri M; Gopakumar, V; Vaidyan, V K(January 17, 2013)
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Abstract:
ZnO thin films were coated on amorphous glass substrate at various temperatures in the
range 160-500 0C by spray pyrolysis method. The as deposited films were characterised by
using XRD and SEM. Wurtzite phase of ZnO was formed at a substrate temperature of
400 0C, highly oriented (002) phase was developed with respect to increase of substrate
temperature from 450 to 500 0C. Morphological and growth mode of these films were
analyzed with respect to structural orientation of films from wurtzite to highly (002)
oriented phase. Present study reveals that substrate temperature was one of the important
parameters which determine the crystalline quality, population of defects, grain size,
orientation and morphology of the films
Description:
Journal of Optoelectronics and Biomedical Materials Vol. 5 Issue 1, January - March 2013 p. 1 - 8
Bessy Raj, B N; Dr.Prathapachandra Kurup,M R(Cochin University of Science and Technology, February , 2009)
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Abstract:
The present work deals with the complexation of Schiff
bases of aroylhydrazines with various transition metal ions. The hydrazone
systems selected for study have long 7I:-delocalized chain in the ligand molecule
itself, which get intensified due to metal-to-ligand or ligand-to-metal charge
transfer excitations upon coordination. Complexation with metal ions like copper,
nickel, cobalt, manganese, iron, zinc and cadmium are tried. Various spectral
techniques are employed for characterization. The structures of some complexes
have been well established by single crystal X-ray diffraction studies. The nonIinaer
optical studies of the ligands and complexes synthesized have been studied
by hyper-Rayleigh scattering technique.The work is presented in seven chapters and the last one deals with
summary and conclusion. One of the hydrazone system selected for study proved
that it could give rise to polymeric metal complexes. Some of the copper, nickel,
zinc and cadmium complexes showed non-linear optical activity. The NLO
studies of manganese and iron showed negative result, may be due to the inversion
centre of symmetry within the molecular lattice.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Rajive, Tomy M; Dr.Jayalekshmi, S(Cochin University Of Science And Technology, July 20, 2012)
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Abstract:
The main challenges in the deposition of cathode materials in thin film form are
the reproduction of stoichiometry close to the bulk material and attaining higher
rates of deposition and excellent crystallinity at comparatively lower annealing
temperatures. There are several methods available to develop stoichiometric thin
film cathode materials including pulsed laser deposition; plasma enhanced
chemical vapor deposition, electron beam evaporation, electrostatic spray
deposition and RF magnetron sputtering. Among them the most versatile
method is the sputtering technique, owing to its suitability for micro-fabricating
the thin film batteries directly on chips in any shape or size, and on flexible
substrates, with good capacity and cycle life. The main drawback of the
conventional sputtering technique using RF frequency of 13.56MHz is its lower
rate of deposition, compared to other deposition techniques A typical cathode
layer for a thin film battery requires a thickness around one micron. To deposit
such thick layers using convention RF sputtering, longer time of deposition is
required, since the deposition rate is very low, which is typically 10-20 Å/min.
This makes the conventional RF sputtering technique a less viable option for
mass production in an economical way.
There exists a host of theoretical and experimental evidences and results that
higher excitation frequency can be efficiently used to deposit good quality films
at higher deposition rates with glow discharge plasma. The effect of frequencies
higher than the conventional one (13.56MHz) on the RF magnetron sputtering
process has not been subjected to detailed investigations. Attempts have been
made in the present work, to sputter deposit spinel oxide cathode films, using
high frequency RF excitation source. Most importantly, the major challenge faced by the thin film battery based on the LiMn2O4 cathode material is the poor capacity retention during charge discharge cycling. The major causes for the capacity fading reported in LiMn2O4cathode materials are due to, Jahn-Teller distortion, Mn2+ dissolution into the electrolyte and oxygen loss in cathode material during cycling. The work discussed in this thesis is an attempt on overcoming the above said challenges and developing a high capacity thin film cathode material.
Description:
Division for Research in Advanced Materials
Department of Physics
Cochin University of Science and Technology
Deepa, Nair G; Alex, Fraaij; Adri, Klaassen A K; Arno, Kentgens P M(Elsevier, 2008)
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Abstract:
Various factors determine the applicability of rice husk ash (RHA) as a pozzolanic material. The amount and accessibility of reactive sites is
thought to be a key factor. A structural study of RHA samples in relation to their reactivity has been performed; Silica in RHA formed by burning
rice husk in a laboratory furnace under continuous supply of air have been characterized as a function of incineration temperature, time and
cooling regime. The characterization methods included chemical analyses, conductivity measurements, microscopic analysis, X-ray diffraction
(XRD) and 29Si magic-angle spinning (MAS) nuclear magnetic resonance (NMR). In line with earlier observations, the analyses show that the
highest amounts of amorphous silica occur in samples burnt in the range of 500 °C–700 °C. The 29Si NMR data allow direct identification of the
reactive silanol sites in the RHA samples. De-convolution of the NMR spectra clearly shows that the quickly cooled RHA resulting from burning
rice husk for 12 h at 500 °C has the highest amount of silanol groups. This sample also induced the largest drop in conductivity when added to a
saturated calcium hydroxide solution giving an indication of its reactivity towards lime. Therefore, this RHA is the favorable sample to be used as
pozzolanic cement additive
Anantharaman, M R; Mathew, George; Asha, Mary John; Swapna, Nair S; Joy, P A(IOP Publishing LTD, February 17, 2006)
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Abstract:
Fine particles of lithium ferrite were synthesized by the sol-gel method.
By subsequent heat treatment at different temperatures, lithium ferrites of
different grain sizes were prepared. A structural characterization of all the
samples was conducted by the x-ray diffraction technique. A grain size of
around 12 nm was observed for Li0.5Fe2.5O4 obtained through the sol-gel
method. Magnetic properties of lithium ferrite nanoparticles with grain size
ranging from 12 to 32 nm were studied. Magnetization measurements
showed that Li0.5Fe2.5O4 fine particles exhibit a deviation from the predicted
magnetic behaviour. The as-prepared sample of lithium ferrite showed a
maximum saturation magnetization of 75 emu g−1. Variation of coercivity is
attributed to the transition from multi-domain to single domain nature.
Dielectric permittivity and ac conductivity of all the samples were evaluated
as a function of frequency, temperature and grain size. Variation of
permittivity and ac conductivity with frequency reveals that the dispersion is
due to the Maxwell–Wagner type interfacial polarization
Sivakumar,S; Prathapachandra Kurup, M R(Department of Applied Chemistry, 2002)
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Abstract:
The primary aim of these investigations was to probe the spectroscopic, electrochemical, biological and single crystal X-ray diffraction studies of some selected transition metal complexes of 4N-monosubstituted thiosemicarbazones. Transition metal complexes with thiosemicarbazones exhibit a wide range of stereochemistries and possess potential biological activity. Metal complexes of thiosemicarbazones are proved to have improved pharmacological and therapeutic effects. The studies are conducted to bring about a fair understanding of the structure activity relationship and to develop certain effective and economical metal-based antimicrobial agents. Study showed that the thiosemicarbazones have antibacterial, antiviral and antiproliferative properties and hence used against tuberculosis, leprosy, psoriasis, rheumatism, trypanosomiasis and coccidiosis. Certain thiosemicarbazones showed a selective inhibition of HSV and HIV infections. The insolubility of most thiosemicarbazones in water causes difficulty in the oral administration in clinical practice. Transition metal complexes are found to have more activity than uncombined thiosemicarbazones. They exhibit a variety of denticity and can be varied by proper substitution. The stereochemistry assumed by the thiosemicarbazones during the coordination with transition metal ions depends on the factors such as preparative conditions and availability of additional bonding site in the ligand moiety and charge of the ligand. The resulting complexes exhibited a wide range of stereochemistries and have biomimic activity and potential application as sensors.
Sivakumar,S; Prathapachandra Kurup, M R(Department of Applied Chemistry, 2002)
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Abstract:
The primary aim of these investigations was to probe the spectroscopic, electrochemical, biological and single crystal X-ray diffraction studies of some selected transition metal complexes of 4N-monosubstituted thiosemicarbazones. Transition metal complexes with thiosemicarbazones exhibit a wide range of stereochemistries and possess potential biological activity. Metal complexes of thiosemicarbazones are proved to have improved pharmacological and therapeutic effects. The studies are conducted to bring about a fair understanding of the structure activity relationship and to develop certain effective and economical metal-based antimicrobial agents. Study showed that the thiosemicarbazones have antibacterial, antiviral and antiproliferative properties and hence used against tuberculosis, leprosy, psoriasis, rheumatism, trypanosomiasis and coccidiosis. Certain thiosemicarbazones showed a selective inhibition of HSV and HIV infections. The insolubility of most thiosemicarbazones in water causes difficulty in the oral administration in clinical practice. Transition metal complexes are found to have more activity than uncombined thiosemicarbazones. They exhibit a variety of denticity and can be varied by proper substitution. The stereochemistry assumed by the thiosemicarbazones during the coordination with transition metal ions depends on the factors such as preparative conditions and availability of additional bonding site in the ligand moiety and charge of the ligand. The resulting complexes exhibited a wide range of stereochemistries and have biomimic activity and potential application as sensors
Abdul,Rashid K K; Dr.Krishnan Nambisan, P N; Dr.Jacob, Chacko(Cochin University of Science and Technology, November , 1986)
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Abstract:
This thesis deals with the studies on the synthesis and characterisation of the complexes of embelin with manganese (II), cobalt(II), nickel (II), copper (II), zinc (II), cadmium (II), chromium (III), iron (III) lanthanum(III), praseodymium (III) neodymium (III) Samarium (III), gadolinium (III) dysprosium (III), yttrium (III) thorium (IV) and uranium (VI). Elemental analysis as well as spectral, thermal and magnetic data were used to ascertain the composition of the complexes and to establish the structures of the metal complexes. Wherever possible, the electronic spectra and magnetic data were used to predict the stereochemistry of the complexes.The thesis is divided into four chapters.
Description:
Division of Chemical
Oceanography, School of Marine Science, Cochin University of Science and Technology
Anantharaman, M R; Lisha, R; Hysen, T; Geetha, P; Avasthi, D K; Ramanujan, R V(IOP Publishing LTD, March 7, 2014)
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Abstract:
Metglas 2826 MB having a nominal composition of Fe40Ni38Mo4B18 is an
excellent soft magnetic material and finds application in sensors and memory
heads. However, the thin-film forms of Fe40Ni38Mo4B18 are seldom studied,
although they are important in micro-electro-mechanical systems/nano-electromechanical
systems devices. The stoichiometry of the film plays a vital role in
determining the structural and magnetic properties of Fe40Ni38Mo4B18 thin
films: retaining the composition in thin films is a challenge. Thin films of 52 nm
thickness were fabricated by RF sputtering technique on silicon substrate from a
target of nominal composition of Fe40Ni38Mo4B18. The films were annealed at
temperatures of 400 °C and 600 °C. The micro-structural studies of films using
glancing x-ray diffractometer (GXRD) and transmission electron microscope
(TEM) revealed that pristine films are crystalline with (FeNiMo)23B6 phase.
Atomic force microscope (AFM) images were subjected to power spectral
density analysis to understand the probable surface evolution mechanism during
sputtering and annealing. X-ray photoelectron spectroscopy (XPS) was
employed to determine the film composition. The sluggish growth of crystallites
with annealing is attributed to the presence of molybdenum in the thin film. The
observed changes in magnetic properties were correlated with annealing induced
structural, compositional and morphological changes
Binitha, N N; Dr.Sugunan, S(Cochin University of Science and Technology, October , 2006)
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Abstract:
Green chemistry boots eco-friendly,natural clays as catalysts in the chemical as well as in the pharmaceutical industry.Industry demands thermal stability,mechanical strength etc for the catalyst and there the modification methods becomes important.Pillaring tunes clays as efficient catalytic templates for shape selective organic synthesis.Here pillared clays are used as promising alternatives for the environmentally hazardous homogeneous catalysts in some industrially important Friedel-Crafts alkylation reactions of arenes with lower alchohols and higher olefins.The layer structure is enhanced upon pillaring and allows the nanocomposite formation with polyaniline to develop today’s nanoscale diameter devices.Present work gives an entry of pillared clays to the world of conducting composite nanofibers.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Manoj, N(American chemical society, August 7, 2006)
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Abstract:
A combined experimental and theoretical study of the absorption spectra of a group of closely related pyrylium
perchlorates 1-11 are presented. Minor changes in the position of the substituents lead to drastic changes in
the absorption spectra in this series of compounds. We have attempted to explain the observed changes using
the x,y-band notation developed by Balaban and co-workers. Absorption spectra of all compounds are compared
with results from time-dependent density functional theory (TDDFT) and Zerner’s intermediate neglect of
differential overlap (ZINDO/S) level calculations. Results of the calculations are in good agreement with
experimental observations and an interesting correlation between Balaban’s notations and the MO transitions
are obtained for simple derivatives. It is suggested that for more complex systems such as R- and â-naphthyl
substituted systems, the empirical method is not appropriate.
Antony,G; Dr.Ranganathan, N(Cochin University of Science and Technology, April , 1986)
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Abstract:
The study evolved from the basic
premise that the existing distribution
structure is not adequate or adaptive to
meet the needs of the expanding manufacturing
sector and the emerging mass market.
The hypothised causes of the problem are
the following: marketing channels
are not used for strategy differentiation
by manufacturers: there are too many intermediaries
in the channels; the distributive
institutions are not adaptive; and there
is very little control over the flow of
products through the channels. These
assumptions about the causes of the problem
have been translated into specific
hypotheses and tested with data. Empirical
analysis, while supporting some of these
hypotheses, challenges certain widely held
notions. The ensuing summary presents the
important findings, in the sequence in
which they are discussed in the study.
Description:
School of Management Studies,Cochin University of Science and Technology
Neson, Varghese; Dr.Syamaprasad,U(Cochin University of Science and Technology, May 2, 2012)
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Abstract:
This thesis Entitled Studies on transport and magnetic properties of nano particle doped mgb2 superconductor for technological applications.The thesis ahead focuses on the establishment of enhanced superconducting properties in bulk MgB2 via nano particle doping and its conversion into mono/multifilamentary wires. Further, an attempt has also been made to develop prototypes of MgB2 coil and conduction cooled current lead for technological applications. The thesis is configured into 6
chapters. The opening chapter gives an idea on the phenomenon of superconductivity, the various types of superconductors and its applications in different fields. The second chapter is an introduction on MgB2 superconductor and its relevance which includes crystal and electronic structure, superconducting mechanism, basic superconducting properties along with its present international status. The third chapter provides details on the preparation and characterization techniques followed through out the study on MgB2. Fourth chapter discusses the effect of processing temperature and chemical doping using nano sized dopants on the superconducting properties of MgB2• Fifth chapter deals with the optimization of processing parameters and novel preparation techniques for wire fabrication. Sixth chapter furnishes the preparation of multifilamentary wires with various filament configurations, their electromechanical properties and it also incorporates the development of an MgB2 coil and a general purpose conduction cooled current lead.
Description:
Applied Super conductivity Group,Material science and technology division,National Institute for Interdisciplinary Science and Technology