A
novel set of valence topological parameters have been derived for 28 alkyl
ethers and they have been used for predicting boiling point, density and
refractive index of these ethers by constructing regression models.
2470
In situ
isothermal reduction of FeCl3 in the nanopores of SiO2
gel matrix
A
mixture of basic copper carbonate and chromium nitrate when heated at about
570 °C gives a mixture of CuO and Cr2O3. Basic copper
carbonate and chromium nitrate when heated at
»270 °C yields a mixture of the
same oxides. The mixture of CuO and Cr2O3 obtained
through the two routes is found to be an effective catalyst for the
decomposition of ammonium perchlorate.
2480
Liquid phase benzylation of o-xylene
over pillared clays
Iron, aluminium and mixed
iron aluminium pillared clays have been prepared by partial hydrolysis
method and doped with 10% Mo, V and Cr. They have been used as catalysts for
benzylation of o-xylene. The results reveal that vanadia incorporated
systems show maximum acidity, Fe pillared systems exhibit maximum activity
and the presence of moisture has a diminishing effect on the rate.
2487
Synthesis and characterisation of
manganese(III) heterochelates
B3LYP density functional with 6-31G* basis set has been used
to estimate ESR proton hyperfine coupling constants for a series of rigid
semidione radical ions. The results of these calculations are in good
agreement with the experimental results.
2496
Observation of multiple MLCT emissions for
a CuIN4 chromophore in rigid matrices
Cavity formation energy is
calculated for water at 298.15K. The solubilities of seven
benzene-hydrocarbon solute vapour mixtures in water have been determined
with this cavity formation energy . The result agrees well with the
experimental values of solubilities.
2506
Solvation behaviour of Cu+ and Ag+
ions in acetonitrile-rich mixtures of benzene and ethanol. A viscometric
study
Viscocities of Bu4NClO4, Bu4NNO3,
AgNO3 and CuClO4 have been determined in
acetonitrile-rich mixtures of benzene and ethanol at 25oC. The
data have been analyzed in terms of Jones-Dole viscosity A and
B-coefficients.
2509
Solvent and
electrode kinetic effects on anodic oxidation of Br–-Br3–-Br2
system on some bare and platinized electrode in some dipolar aprotic
solvents from cyclic voltammetric measurements
Solvent and electrode kinetic effects on the anodic
oxidation of Br–-Br3–-Br2
system involving Br–/Br3– and Br3–/Br2
redox couples, have been studied on bare, platinized Pt and C surfaces by
cyclic voltammetric measurements in acetonitrile, N,N–dimethylformamide
and propylene carbonate and in water on bright Pt surface. The observed
ks values for both the redox couples reflect that the
electrocatalytic activities of the electrodes are in the order C < Pt
£
(Pt) Pt < (C)Pt
2513
Density and
viscosity of ternary liquid mixtures of squalane with (hexane+benzene), (cyclohexane+benzene)
and (hexane+cyclohexane) at 298.15 K
Densities and viscosities for
three ternary mixtures of squalane with (hexane+benzene), (cyclohexane+benzene)
and (hexane+cyclohexane) have been measured over the entire composition
range at 298.15 K and at atmospheric pressure. The results have been
discussed in terms of interactions between the components of liquid
mixtures, and the effects of size and shape of the components on excess
properties.
2518
Reexamination of the reactivity of iron
carbonyls with 1,2-ethanedithiol
Copper soaps prepared from various
vegetable oils like groundnut, mustard, sesame and soyabean have been
analyzed for their micellar characteristics. The studies of various
interactions suggest that solute-solvent interaction increases with the
increase in content of shorter fatty acid in the composition of vegetable
oil and lowering of molecular weight whereas solute-solute interaction
decreases.
2531
Two
pentacoordinate copper(II) complexes that display accessible Cu(III/II)
couples
An extractive spectrophotometric method
for the determination of microamounts of ascorbic acid is described. The
method is successfully used in the determination of ascorbic acid in pure
vitamin C tablets, drops and multivitamin products.
Optimization of regression model for predicting physicochemical
properties of alkyl ethers
Minati Kuanar, Saroj K Kuanar, Sabita Patel & Bijay K Mishra*
A novel set of valence topological parameters
have been derived for 28 alkyl ethers. Alongwith some connectivity and Wiener
parameters, these parameters have been used for predicting boiling point (r =
0.996), density (r = 0.884) and refractive index (r = 0.978) of these ethers by
constructing regression models. These models have been optimized by successive
exclusion of variables.
Intimately mixedFeCl3
and dextrose are distributed through out the nanometric pores of silica gel. The
subsequent heat treatment in the temperature range 900 to 1000oC
under nitrogen atmosphere leads to the reduction of FeCl3 to
nanometric metallic iron by in situ hydrogen. The EPR analysis of the
heat-treated samples shows the presence of metallic iron. The mechanism of in
situ reduction kinetics of FeCl3 in silica gel is nucleation and
growth type.
Co-precipitation of a mixture of CuO and
Cr2O3 through NaNO3-KNO3 eutectic
mixture and its catalytic activity
N B Singh & A K Ojha
When a mixture of basic copper
carbonate and chromium nitrate in 1:1 molar ratio has been heated at about 570
°C a mixture of CuO and Cr2O3 is obtained. Further, when
basic copper carbonate and chromium nitrate are mixed in 1:1 molar ratio in NaNO3-KNO3
eutectic mixture and heated at »270 °C
i.e. at a much lower temperature, again a mixture of the same oxides has been
obtained. The formation of the oxides is confirmed by powder X-ray diffraction
technique. The mixture of CuO and Cr2O3 obtained through
the two routes is found to be an effective catalyst for the decomposition of
ammonium perchlorate.
Liquid phase benzylation of o-xylene over pillared
clays
Manju Kurian &
S Sugunan*
Iron, aluminium and mixed iron
aluminium pillared clays have been prepared by partial hydrolysis method and
doped with 10% Mo, V and Cr. The samples have been characterised by XRD, FTIR
and surface area and pore volume measurements. The surface acid site
distribution has been determined by temperature programmed desorption of
ammonia. Vanadia incorporated systems show maximum acidity. Benzylation of o-xylene
has been done as probe reaction to test catalytic activity. Benzyl chloride is a
superior benzylating agent compared to benzyl alcohol in activity and
selectivity. Cent percent selectivity towards monobenzylated product is obtained
in all the cases. Fe pillared systems exhibit maximum activity. The catalytic
activities of the systems can be correlated with the amount of strong acid
sites. The effects of various reaction variables on the reaction have been
studied. Presence of moisture has a diminishing effect on the reaction rate.
Synthesis and characterisation of
manganese(III) heterochelates#
Ismail A Patel, Pankaj Patel, S Goldsmith & B T Thaker*
Manganese(III) complexes of the type: (i) [Mn(Sal-o-phen)Bzp].2H2O,
(ii) [Mn(Bzp-o-phen)Sal].2H2O, (iii) [Mn(Acp-en) 1, 10 phen]ClO4
and (iv) [Mn(Acp-en) 2, 2¢
dipy]ClO4 (where, Sal-o-phen and Bzp-o-phen are the Schiff
bases derived from salicylaldehyde and
1-phenyl-3-methyl-4-benzoyl-2-pyrazoline-5-one and o-phenylenediamine
respectively; Acp-ethylene is a Schiff base derived from
1-phenyl-3-methyl-4-acetyl-2-pyrazoline-5-one and ethylenediamine; 1, 10 phen =
1, 10 phenanthroline and 2, 2¢
dipy = 2, 2¢
dipyridyl) have been prepared and their physico-chemical properties studied. The
former two complexes are non-electrolytes and the later two are 1:1 electrolytes
in solution. Magnetic moment values close to 4.9 B.M. indicate the presence of
Mn(III) complexes with four unpaired electrons and lack of any kind of exchange
interaction. On the basis of analytical and physical data a tetragonally
distorted octahedral structure is suggested for all of the complexes. The
complexes were treated for TGA and DTA studies. From the TGA curves,
thermo-kinetic parameters such as activation energy (E), order of
reaction (n), pre-exponential factor (A) and entropy change (DS)
have been calculated using different methods suggested by Horowitz-Metzger,
Freeman-Carroll, Coats-Redfern and Sharp-Wentworth.
B3LYP density functional with 6-31G* basis set has been used
to estimate ESR proton hyperfine coupling constants for a series of rigid
semidione radical ions. The calculated estimates are in excellent agreement with
experimental results. Single- point UB3LYP calculations have also been made
using UHF/3-21G and UAM2 optimized geometries. Interestingly, the results of
these computationally cheaper calculations are also in good agreement with the
experimental results.
[CuL2]ClO4
(1), where L is a 1:2 condensate of ethylenediamine and
benzophenone, displays four MLCT emissions with maxima lem
= 617, 583, 549 and 494 nm in poly(methyl methacrylate) matrix at room
temperature. Three of these emissions are observed for 1 in methanol
glass at 77 K with lem
= 473, 440 and 412 nm. The origins of these emissions are investigated by
Extended Hückel calculations on [CuL2]+ at the
crystallographically determined geometry.
Aqueous solubility of benzene-hydrocarbon binary solute vapor
mixture
A Guha* & Debaprasad Panda
Cavity formation energy (CFE) which is equivalent to the free
energy cast of insertion of a hard sphere solute in a hard sphere solvent is
calculated for water at 298.15K. The solubilities of seven benzene-hydrocarbon
solute vapor mixtures in water has been determined with this CFE. The result
agrees well with the experimental values of solubilities. The method has also
been used to calculate physico-chemical properties of solvent and solute
molecules. The calculation shows the importance of cavity formation energy in
determining the solubility and other physico-chemical properties.
Solvation behaviour of Cu+
and Ag+ ions in acetonitrile-rich mixtures of benzene and ethanol. A
viscometric study
M S Chauhan*, K Sharma & G Kumar
Viscocities of Bu4NClO4, Bu4NNO3,
AgNO3 and CuClO4 have been determined in acetonitrile-rich
mixtures of benzene and ethanol at 25oC. The data have been analyzed
in terms of Jones-Dole viscosity A and B-coefficients. Ionic contributions B±
values were obtained on the basis of Bu4NBPh4 assumption.
Effective ionic radii (Ri) of ClO4-, NO3-,
Cu+ and Ag+ have been calculated from the relation: B±
= 2.5 (4¤3)p
Ri3 N/3000. An examination of Ri values as a
function of solvent composition suggests the existence of specific ion-solvent
interactions in the case of Cu+ and Ag+ ions. A
contribution due to hydrogen bond formation is however observed in acetonitrile-ethanol
mixture in case of ClO4- and NO3-
anions. A reasonably good agreement in respect of Ri values of all
ions with those obtained earlier from conductance measurements is attributed to
the fact that the solvated ionic species exist as rigid spherical entities
during the viscous flow process.
anodic oxidation of Br–-Br3–-Br2
system on some bare and platinized electrode in some dipolar aprotic solvents
from cyclic voltammetric measurements
J Datta*, C Bhattacharya, S Sinha & K K Kundu
Solvent and electrode kinetic effects on the anodic oxidation
of Br–-Br3–-Br2 system involving Br–/Br3–
and Br3–/Br2 redox couples, have been studied
on bare and platinized Pt and C surfaces by cyclic voltammetric (CV)
measurements in some dipolar aportic solvents like acetonitrile, N,N–dimethylformamide
and propylene carbonate and in water on bright Pt surface. The rate constants (ks)
have been evaluated by Shain and Nicholson’s formulations as appropriate to the
irreversible and quasi-reversible CV waves observed in different cases. Kinetic
solvent effects on both the redox reactions on Pt surface in different solvents
have been analyzed in the light of initial and transition state (TS) solvation
using the previously determined solvation free energies of Br–, Br3–
and Br2 in the respective solvents. The observed ks
values for both the redox couples reflect that the electrocatalytic activities
of the electrodes are in the order C < Pt £
(Pt) Pt < (C)Pt, as are expected from the combined effects of geometric and
electronic characters of the involved electrode surfaces.
Density and viscosity of
ternary liquid mixtures of squalane with (hexane+benzene), (cyclohexane+benzene)
and (hexane+cyclohexane) at 298.15 K
S C Bhatia*, Neelima Tripathi & G Prakash Dubey
Densities (r) and viscosities (h)
for three ternary mixtures of squalane with (hexane+benzene), (cyclohexane+benzene)
and (hexane+cyclohexane) have been measured over the entire composition range at
298.15 K and at atmospheric pressure. The excess molar volumes,
and viscosity deviations,
dh have been calculated from
experimental measurements. The results have been discussed in terms of
interactions between the components of liquid mixtures, and the effects of size
and shape of the components on excess properties.
Reexamination of the reactivity of
iron carbonyls with
1,2-ethanedithiol
S E Kabir*, A F
M M Rahman, J Parvin & K M A Malik
The reactions of 1,2-ethanedithiol with [Fe3(CO)12],
Na2[Fe(CO)4], Na2[Fe2(CO)8]
and Fe(CO)5 afforded the previously reported dinuclear compound [Fe2(CO)6(µ-SCH2CH2S)]
1. The reactions ofNa2[Fe(CO)4] with 1,2-
ethanedithiol in presence of [Cp2TiCl2] both at room
temperature and at 68oC also gave 1. Treatment of [CpFe(CO)2]2
with 1,2- ethanedithiol at 110oC yielded 1a, which is
cocrystallized with ferrocene (2:1 ratio), formed from the same reaction.
Spectroscopic data and single crystal X-ray diffraction studies of 1a are
reported.
Studies on the copolymerisation of n-alkyl
itaconates
with styrene
Gulshan
Kumar, Saroj Aggarwal* &
Veena Choudhary
The synthesis and characterization of
n-hexyl itaconate (HI) and n-octyl itaconate (OI) monomers and
their homopolymerisation and copolymerisation with styrene in bulk using
azobisisobutyronitrile (AIBN) as an initiator have been reported. Copolymer
composition has been determined from 1H-NMR by taking the ratio of
intensities of signals due to -OCH2 protons of itaconates (δ =3.9 ppm)
and aromatic protons of styrene (δ =6.8-7.2 ppm). The intensity of signal due to
-OCH2 proton increases with increasing mole fraction of itaconate
monomers in the feed. The reactivity ratios are found to be r1 = 1.2
(styrene), r2 = 0.75 (HI) and r1 = 1.38 (styrene), r2
= 0.62 (OI). All the samples have high moleculer weight, i.e., Mn
in the range of 40 ×103 to 62 ×103 and Mw
in the range of 43 ×103 to 113 ×103 with polydispersity
index in the range of 1.64 - 1.85. Intrinsic viscosity [h]
of the copolymers decreases with increasing amount of itaconate in the
copolymers. Inspite of having very high molecular weight (77,000-78,000) the
homopolymers (PHI, POI) have a very low value of [h]
(4±0.5
ml/g). These low values of [h]
may be due to the presence of long branches in itaconates showing comb type
structure. Thermal studies of the copolymers show all the samples to be stable
up to 300oC.
Micellar features and other
solution properties of
copper(II) soaps in benzene
M R K
Sherwani, Rashmi Sharma*, Antima Gangwal & Renu Bhutra
Copper soaps prepared from various vegetable oils have been
analyzed for their micellar characteristics. Density of copper surfactants of
groundnut, mustard, sesame and soyabean oils in benzene has been measured and
using density data, molar volume and apparent molar volume have been evaluated.
These parameters show a change at cmc suggesting the micellar behaviour of the
soaps. The critical micelle concentration are found to decrease with increase in
average molecular weight of the soap. The apparent molar volume has been
examined in terms of Masson equation. The limiting apparent molar volume (фvo)
has been interpreted in terms of solute-solvent interaction while limiting slope
(sv) in terms of solute-solute interaction. The studies of various
interactions suggest that solute-solvent interaction increases with the increase
in content of shorter fatty acid in the composition of vegetable oil and
lowering of molecular weight whereas solute-solute interaction decreases.
Two pentacoordinate copper(II)
complexes that display accessible Cu(III/II) couples
Michael G B Drew, Jnan P Naskar, Shubhamoy Chowdhury &
Dipankar Datta*
Two copper(II) complexes of the type CuL2.imidazole
(1) and Cu2L4(4,4¢-bpy).2H2O.C6H14
(2), where LH = 1-nitroso-2-naphthol and 4,4¢-bpy
= 4,4¢-bipyridine, are characterised by
X-ray crystallography. In 2, the two copper atoms are linked by 4,4¢-bpy.
In both the complexes, copper is found to have a distorted square pyramidal N3O2
coordination sphere. The axial position in 1 is occupied by an oxygen
atom while those in 2 by the nitrogen atoms of 4,4¢-bpy.
The two complexes display quasireversible Cu(III/II) couples around 0.68 V
vs. saturated calomel electrode in cyclic voltammetry in dichloromethane.
Synthesis, biological and
catalytic properties of Ru(II) benzamides Schiff base complexes
B S Jhaumeer-Laulloo & Minu G Bhowon*
A few Schiff bases (p-chlorobenzaldehyde)-benzylimine 1, (salicylaldehyde)-p-toluidiimine
2, bis(p-anisaldehyde)-ethylenediimine 3,
bis(1-naphthaldehyde)-p-phenylenediimine 4, bis(m-nitrobenzaldehyde)-p-phenylenediimine
5, and bis(salicylaldehyde)-o-phenylenediimine 6 have been
synthesized and reacted with Ru2Cl2(DNBH)(H2O)4
(TR1) to yield six binuclear ruthenium complexes 1a-6a. All the complexes
are characterized by spectroscopic, elemental and magnetic susceptibility data.
The coordination is found to be through carbonyl oxygen of amide, phenolic
oxygen and azomethine nitrogen of the Schiff bases in the octahedral environment
of the metal. All the metal complexes show antibacterial and catalytic activity.
Thenoyltrifluoroacetone as a spectrophotometric reagent for determination of
ascorbic acid
Satya
Prakash Arya* & Preeti Jain
An
extractive spectrophotometric method for the determination of microamounts of
ascorbic acid is described. 1-[Thenoyl- (2¢)-3,3,3-trifluoro-acetone]
(HTTA) is found to react with iron (III) in strongly acidic medium giving a red
coloured complex. The method is based on the proportionate decrease in the
colour intensity of Fe(III)-HTTA complex with the addition of ascorbic acid at
405 nm. Linear calibration curve is observed in the range 1.0-5.0 mg/mL
of ascorbic acid. The molar absorptivity and Sandell’s sensitivity are 5.3´104
L/mol/cm and 0.003µg/cm2, respectively. The interference of sugars,
vitamins, amino acids, mineral salts, sweetening agents etc. has been studied.
The method is successfully used in the determination of ascorbic acid in pure
vitamin C tablets, drops and multivitamin products.
