Mohammed Yusuff, K K; Digna, Varghese; Arun, Vasudevan; Robinson, P P; Manju, Sebastian; Leeju, P; Varsha, Gopalakrishnan(International Union of Crystallography, Acta Crystallographica Section C ,Crystal Structure Communications, November 11, 2009)
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Abstract:
The Schiff base compounds N,N0-bis[(E)-quinoxalin-2-ylmethylidene]
propane-1,3-diamine, C21H18N6, (I), and N,N0-bis[(E)-
quinoxalin-2-ylmethylidene]butane-1,4-diamine, C22H20N6,
(II), crystallize in the monoclinic crystal system. These
molecules have crystallographically imposed symmetry.
Compound (I) is located on a crystallographic twofold axis
and (II) is located on an inversion centre. The molecular
conformations of these crystal structures are stabilized by
aromatic pye stacking interactions.
Mohammed Yusuff, K K; Manju, Sebastian; Arun, Vasudevan; Robinson, P P; Leeju, Pally; Digna, Varghese; Varsha, Gopalakrishnan(Taylor & Francis, Journal of Coordination Chemistry, October 15, 2009)
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Abstract:
The mononuclear cobalt(II) complex [CoL2] H2O (where HL is quinoxaline-2-carboxalidine-
2-amino-5-methylphenol) has been prepared and characterized by elemental analysis, conductivity
measurement, IR, UV-Vis spectroscopy, TG-DTA, and X-ray structure determination.
The crystallographic study shows that cobalt(II) is distorted octahedral with each tridentate
NNO Schiff base in a cis arrangement. The crystal exhibits a 2-D polymeric structure parallel to
[010] plane, formed by O-H...N and O-H... O intermolecular hydrogen bonds and pye
stacking interactions, as a racemic mixture of optical enantiomers. The ligand is a Schiff base
derived from quinoxaline-2-carboxaldehyde
Mohammed Yusuff, k K; Varsha, Gopalakrishnan; Arun, Vasudevan; Manju, Sebastian; Leeju, P; Digna, Varghese(Crystallography Journals,Acta Crystallographica Section E ,Structure Reports, March 24, 2009)
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Abstract:
The asymmetric unit of the title compound, C11H8N4, contains
two independent molecules. In the crystal structure, intermolecular
N—H.....N hydrogen bonds link molecules into
ribbons extended in the [100] direction
Mohammed Yusuff, K K; Digna, Varghese; Arun, Vasudevan; Manju, Sebastian; Leeju, P; varsha, Gopalakrishnan(Crystallography Journals,Acta Crystallographica Section E ,Structure Reports, January 23, 2009)
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Abstract:
In the molecule of the title compound, C20H16N6, the central
C—C bond lies on a crystallographic inversion centre. The
quinoxalidine ring is nearly planar, with a maximum deviation
of 0.021 (2) A ˚ from the mean plane. The crystal structure is
stabilized by intermolecular C—H....N interactions, leading to
the formation of a layer-like structure, which extends along the
a axis
Girish Kumar, K; Joseph, Renjini(Taylor & Francis, June 1, 2009)
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Abstract:
A metalloporphyrin incorporated carbon paste sensor has been developed
for the determination of metronidazole benzoate (MTZB). Zn(II) complex
of 5,10,15,20-tetrakis (3-methoxy-4-hydroxy phenyl) porphyrin (TMHPP) was
used as the active material. The MTZB gave a well-defined reduction peak at
- 0.713V in 0.1 mol l -1 phosphate buffer solution of pH around 7. Compared
with bare carbon paste electrode (CPE), the TMHPP Zn(II) modified electrode
significantly enhanced the reduction peak current of MTZB as well as lowered
its reduction potential. Under optimum conditions the reduction peak current
was proportional to MTZB concentration over the range 1×10-3 mol1-1 to 1×10-5mol1-1. The detection limit was found to be 4.36×10-6mol1-1
. This
sensor has been successfully applied for the determination of MTZB in pharmaceutical
formulations and urine samples.
Mohammed Yusuff, K K; Arun, Vasudevan; Robinson, P P; Manju, Sebastian; Leeju, P; Varsha, Gopalakrishnan; Digna, Vasudevan(Elsevier, Dyes and Pigments 82 (2009) 268–275, January 18, 2009)
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Abstract:
A novel bisazomethine Schiff base was synthesised by the condensation of 3-hydroxyquinoxaline-2-
carboxaldehyde and 2,3-diaminomaleonitrile. 1H NMR, 13C NMR, HPLC and FT-IR studies revealed that
the compound exists in two major tautomeric forms. The Schiff base exhibits positive absorption and
fluorescent solvatochromism and displays dual fluorescence with large stoke shifts. Cyclic voltammetric
analysis of the compound in 1:1 methanol–THF was influenced by scan rate. Thermal analysis of the
compound was undertaken using TG–DTA and DSC
Mohammed Yusuff, K K; Arun, Vasudevan; Sreedevi, N; Robinson, P P; Manju, Sebastian(Elsevier,Journal of Molecular Catalysis A: Chemical 304 (2009) 191–198, February 7, 2009)
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Abstract:
Two new complexes, [MII(L)(Cl)(H2O)2]·H2O (where M=Ni or Ru and L = heterocyclic Schiff base, 3-
hydroxyquinoxaline-2-carboxalidene-4-aminoantipyrine), have been synthesized and characterized by
elemental analysis, FT-IR, UV–vis diffuse reflectance spectroscopy, FAB-MASS, TG–DTA, AAS, cyclic
voltammetry, conductance and magnetic susceptibility measurements. The complexes have a distorted
octahedral structure andwere found to be effective catalysts for the hydrogenation of benzene. The influence
of several reaction parameters such as reaction time, temperature, hydrogen pressure, concentration
of the catalyst and concentration of benzenewas tested. A turnover frequency of 5372 h−1 has been found
in the case of ruthenium complex for the reduction of benzene at 80 ◦C with 3.64×10−6 mol catalyst,
0.34 mol benzene and at a hydrogen pressure of 50 bar. In the case of the nickel complex, a turnover
frequency of 1718 h−1 has been found for the same reaction with 3.95×10−6 mol catalyst under similar
experimental conditions. The nickel complex shows more selectivity for the formation of cyclohexene
while the ruthenium complex is more selective for the formation of cyclohexane
The heterogeneous photocatalytic degradation of methylorange over TiO2 is studied
and is found to be cost effective. Effect of Zirconium metal incorporation over titania system is investigated. Photocatalytic degradation of methylorange using solar radiation is
found to be highly economical when compared with the processes using artificial UV
radiation, which require substantial electrical power input. The characterization of titania as
well as modified zirconium metal doped titania systems are done using XRD, FTIR and
EDAX measurements. The catalytic activities of different systems are also compared and is
tried to correlate with the crystallite size and presence of dopant metal.
George, K E; Jacob, Sinto; Suma, K K; Mendaz, Jude Martin; George, Abhilash(Wiley InterScience, 2009)
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Abstract:
Poly(propylene) (PP) reinforced with short glass fiber was modified with
precipitated nanosilica (pnS) by melt mixing. The weight of the glass fiber was varied
by keeping the pnS at optimum level. The properties of the composites were studied
using universal testing machine, dynamic mechanic analyser (DMA), differential
Scanning calorimetry (DSC) and thermo gravimetric analyser (TGA). The amount of the
glass fiber required for a particular modulus could be reduced by the addition of
nanosilica.
Low-protein content natural rubber latex
was produced by using a nonionic surfactant-polyethylene
glycol (PEG). Extractable protein content of natural rubber
latex was found to decrease with PEG treatment and
reduction increased with increase in the molecular weight
of PEG. The low-protein latex samples were characterized
by tensile testing, Fourier transform infrared and thermogravimetric
analysis. The results have shown 35% reduction in the extractable protein content, without any compromise
on the mechanical properties of the latex; however,
thermal stability of low-protein latex was found to be
reduced marginally with PEG treatment.