Indian Journal of Chemistry
Vol. 46A, December 2007, pp.
1911-1916
Theoretical studies on stable geometries of
C78O6 based on C2v-C78
W Zhang,, S Wu*
& X Wen
Received 20 June 2007; revised 29 September 2007
The semi-empirical AM1 and INDO/CIS methods as well as
density function theory have been used to study equilibrium geometries and spectroscopic
properties of the possible isomers of C78O6 based on C2v-C78. The most stable geometry at the ground
state of C78O6 is found to be 28, 29, 30, 31, 52, 53, 70,
71, 73, 78, 75, 76-C78O6 (A). TheC(70)-C(71) and
C(75)-C(76) bonds are opened up to form annulene-like structures, whereas the
other four bonds are not broken and show epoxy features in C78O6
(A). The oxygen atoms added tend to approach the sites vacated by the previous
oxygen atoms since the conjugation system in C2v-C78
is destroyed at these sites. Based on the B3LYP/6-31G optimized geometries, the
main absorptions in the electronic spectra and the stretching vibrations of the
C=C bonds in the IR spectra of C78O6 isomers are blue
shifted as compared with those of C2v-C78 calculated using
the INDO/CIS and AM1 method, respectively. The chemical shifts of the carbon
atoms in the epoxy and annulene-type structures of C78O6
isomers, calculated at B3LYP/6-31G level, move upfield.
Indian Journal of Chemistry
Vol. 46A, December 2007, pp.
1917-1922
Electrochemical study on effect of colloidal
Au on horseradish peroxidase in polypyrrole layer at prussian blue modified
electrode
Yingju Liu, *,
Qiaoyi Hu & Bimin Lin
Received 12 November 2006; revised 12 October
2007
Cyclic voltammetry and current-time curve have been used to
investigate the Au-colloid function on the horseradish peroxidase biosensor
response. Firstly Prussian blue is deposited
on the electrode, and then the
polypyrrole (PPY)/HRP biosensor is constructed by electrochemical
oxidization of pyrrole in the solution containing horseradish peroxidase and
pyrrole.. The colloidal
Au is then immobilized on the electrode. Cyclic voltammograms
show higher current in the presence of Au-colloid as compared to that in the
absence of the colloid. The PB/PPY/HRP and PB/PPY/HRP/Au-colloid biosensors
exhibit linear current-time response to hydrogen peroxide over a concentration
range of 2´10-6 M –
1.8´10-4 M. ,
Michaelis-Menten constants of the two
biosensors are 0.63 and 0.35 mM,
respectively. The dependence of current responses on applied voltage
has been discussed, and the mechanism has been proposed.
The results show that colloidal Au enhances the
current response and decreases the
energy -barrier
of electron transfer
reaction on the electrode. The interference of foreign substances has also
discussed.
IPC Code: Int. Cl.8
B01J; C25B3/02
Indian Journal of Chemistry
Vol. 46A, December 2007, pp.
1923-1928
Electrochemical characterization of
composite films of polypyrrole and La1-xSrxCoO3
(0 ≤ x ≤ 0.4) for electrocatalysis of O2 reduction
R N Singh*, M
Malviya & Anindita
Received 18 April 2007; revised 22 October 2007
Sandwich-type composite films of polypyrrole (PPy) and La1-xSrxCoO3
(0 ≤x≤0.4) on a conductive graphite support (G) have been obtained
by electropolymerization for electrocatalysis of the oxygen reduction reaction
(ORR). The composite films have been characterized by SEM, EDAX, cyclic
voltammetry, impedance and Tafel polarization techniques. The studies show that
the composite electrodes are greatly active for the ORR than the non-composite
one. The higher Sr substitutions (>0.2 mol) have an adverse effect on the
electrocatalytic activity. The rate for the ORR at the composite film has been
found to decrease with decreasing pH of
the electrolyte. Among all the four composite electrodes studied, the
G/PPy/PPy(La0.8Sr0.2CoO3)/PPy electrode in 0.5
mol dm-3 K2SO4 plus 5 m moldm-3 KOH at
25°C
exhibits the highest electrocatalytic activity towards the ORR.
IPC Code: Int. Cl.8
B01J23/00; C25D
Indian Journal of Chemistry
Vol. 46A, December 2007, pp.
1929-1937
Physicochemical behaviour of copper(II)
complexes of chelated diamine ligands: Catalytic role of
diaquabis(ethylenediamine)copper(II) perchlorate in acylal formation
Purabi Sarmah, Sunita Singha, Rajesh Chakrabarty, Sanchay J
Bora & Birinchi K Das*
Received 18 September 2007; revised 2 November
2007
Preparation and properties of a few chelated diamine
complexes of copper(II) are reported. The compounds, [Cu(en)2(H2O)2](ClO4)2
(1), [Cu(tmen)2(H2O)2](ClO4)2
(2), [Cu2(en)2Cl4]n (3) and [Cu2(en)2(SO4)2(H2O)4].2H2O (4)
have been prepared in moderate to excellent yields and characterized by various
physicochemical techniques. The structure of [Cu2(en)2Cl4]n
(3) has been determined by single
crystal X-ray diffraction. Complex 3
crystallizes in monoclinic space group P21/m,
with unit cell parameters a = 6.7850 (14) Å, b = 5.7600(12)Å, c
= 8.2240(16)Å, b = 93.75(3)º, V
= 320.7(1)Å3. The structure has been solved by direct method and
refined by full-matrix least squares to final R1 = 0.0460, wR2 = 0.1249 and GooF = 1.135 for all 818 reflections.
Each copper atom in complex 3 is
present in a distorted octahedral environment created by a chelating
ethylenediamine ligand and four chlorine atoms. Two adjacent parallel
–Cu–Cl–Cu– chains joined by short Cu–Cl bonds give rise to a zigzag ribbon-like
polymer. Complex 1 has been studied as a catalyst for the conversion of
aromatic aldehydes to acylals under solvent-free conditions at room
temperature.
IPC Code: Int. Cl.8 C07F1/08
Indian Journal of Chemistry
Vol. 46A, December 2007, pp.
1938-1946
Synthesis, physicochemical characterisation
and chemical properties of the first nonaalkoxo-distannates and dititanates of
nickel(II)
Neetu Agrawal & Anirudh Singh*
Received 2 May 2007; revised 24 October 2007
Heterobimetallic alkoxides of the types [Ni{M2(OR)9(m-Cl)}]2 (1)-(4)and [Ni{M2(OR)9}2] (5)-(8) (where M = Sn, Ti; R = Pri, Et) have been
prepared by the reactions of NiCl2.xROH (R = Pri, Et) with M´{M2(OR)9}
(M´ = Na, K) in 1:1 and 1:2 molar ratios in benzene, respectively. The chloro
complexes (1)-(4) on reactions with appropriate alkali metal alkoxides yield
alkoxo analogues: [Ni{Sn2(OPri)9}(m-OPri)]2 (10), [Ni{Sn2(OEt)9}(m-OEt)]2 (11), [Ni{Ti2(OPri)9}(m-OPri)]2 (12), [Ni{Ti2(OEt)9}(m-OEt)]2 (13), [Ni{Sn2(OPri)9}(m-OCH2CH2OCH3)]2
(14), [Ni{Sn2(OEt)9}(m-OCH2CH2
OCH3)]2 (15),
[Ni{Sn2(OPri)9} (m-OCH2CH2OC2H5)]2
(16),
[Ni{Sn2(OEt)9}(m-OCH2CH2OC2H5)]2
(17), [Ni{Sn2 (OPri)9}(m-OCH2CH2NHCH3)]2
(18), and [Ni{Sn2(OEt)9}(m-OCH2CH2NHCH3)]2
(19). All these complexes have been
characterized by elemental analyses, spectroscopic (UV-vis, and IR) and
magnetic studies as well as by molecular weight measurements.
IPC Code: Int. Cl.8 C0F15/04
Indian Journal of Chemistry
Vol. 46A, December 2007, pp.
1947-1950
Synthesis and crystal structure of an
iron(II) dimeric complex
Partha Roy, Koushik Dhara, Jishnunil Chakraborty, Munirathinam
Nethaji & Pradyot Banerjee*
Received 27 July 2007; accepted 30 October 2007
An iron(II) complex, [Fe2(salen)2] has
been prepared by the reaction of [FeIII(salen)Cl] with copper(II)
malonate dihydrate [salen = N,N¢-ethylenebis(salicylideneiminato) dianion] in
N,N-dimethylformamide-water mixture. The complex has been characterized by
FT-IR spectroscopy, UV-vis spectra, thermogravimetric analysis, cyclic
voltammetry and X-ray crystallography. The iron(II) complex 1 crystallizes in the monoclinic, space group C2/c, a = 26.664(5)
Å, b = 6.9943(11) Å, c =
14.727(2) Å, β =
97.498(3)°,
and Z = 8. The structural study
reveals that it is a penta-coordinate Fe(II) dimeric complex.
IPC Code: Int Cl.8 C07F15/02
Indian Journal of Chemistry
Vol. 46A, December 2007, pp.
1951-1954
Preparation and characterization of thelanthanide
complex Eu(TTA)3phen / vinylpyrrolidone luminescent nanofiberby
electrospinning
Liu Wei * & Wang Ce
Received 15 January 2007; revised 12 October
2007
Eu(TTA)3phen/vinyl pyrrolidone (PVP) composite nanofibers have
been prepared by electrospinning technique. The spectral properties of Eu(TTA)3phen/PVP composite nanofibers have
been studied, as compared to that of Eu(TTA)3phen
powders. The excitation of Eu(TTA)3phen/PVP systems by UV light results
in a ligand-to-metal energy transfer and the emission spectra display
characteristic luminescence of the central ions (5D0→7F2
for Eu3+). Photoluminescence measurements show that Eu(TTA)3phen/PVP
nanofibers have higher intensity and longer lifetime than that of Eu(TTA)3phen powders
because of the influence of PVP on the coordinative environment of lanthanide
ions.
IPC Code: Int. Cl.8 B82B; C07F5/00
Indian Journal of Chemistry
Vol. 46A, December 2007, pp.
1955-1958
Preparation of silica nanoparticle through
coating with octyldecyltrimethoxy silane
N Venkatathri
Received 13 March 2007; revised 29 October 2007
Silica nanoparticles have been prepared using
tetrethylorthosilicate, water, aqueous ammonia, ethanol and octadecyltrimethoxy
silane as constituents. Kinetics studies have been carried out to characterize
the material by analyzing the yield, which follows an S type curve. At the
eighth hour, the yield reaches maximum in time (hours) versus yield (%) plot.
In conventional synthesis, a part of the product particles is small in size
(100 nm, 80%) while the remaining is bigger in size (300 nm, 20%). The particle
size is normalized on addition of octadecyltrimethoxy silane and is increased
to a small extent(400 nm). The sample has been analyzed by XRD, SEM, TEM,E-DAX,
FT-IR, N2 adsorption and 28Si MASNMR techniques. The
sample is amorphous with surface area of 93.54 m2/g and contains Q2,
Q3 and Q4 species. TEM reveals the particles to be core
shell type which is absent in ODTS-free samples. The samples show Si-O-Si
tetrahedral skeletal vibrations.
IPC Code: Int. Cl.8 B82B3/00
Indian Journal of Chemistry
Vol. 46A, December 2007, pp.
1959-1962
Synthesis and
crystal structure of the zinc(II) complex of
5-(2,3-dimethyl-1-phenyl-3-pyrazolin-5-one-4-ylhydrazono) hexahydropyrimidine
-2-thioxo-4,5,6-trione
V Sadasivan & M Alaudeen*
Received 6 March 2007; revised 24 October 2007
Arylazo barbituric acid prepared by coupling diazotized
4-aminoantipyrine with 2-thiobarbituric acid is tautomerised to its hydrazone
form, 5-(2,3-dimethyl-1-phenyl-3-pyrazolin-5-one-4-ylhydrazono)hexahydropyrimidine-2-thioxo-4,
5, 6-trione [HTB-AAP] and acts as a tridentate monovalent ligand towards
zinc(II) as evidenced by IR, 1H-NMR and electronic spectra. The
single crystal X-ray study of [Zn(TBAAP)(H2O)2]NO3.DMSO
reveals that the coordinating sites are the azomethine nitrogen and the two
carbonyl oxygen atoms on the pyrazolone and the thiobarbituric acid rings. The
zinc(II) ion is five coordinated and nitrate is in the ionic state. Thermal
studies support the presence of two coordinated water molecules. XRD
investigations confirm the presence of one molecule DMSO as solvate in the
complex.
IPC Code: Int. Cl.8
C07F5/00
Indian Journal of Chemistry
Vol. 46A, December 2007, pp.
1963-1968
Complexes of ruthenium(III), rhodium(III)
and iridium(III) with ligands bearing 2,6-diacetylpyridine
bis(S-alkylisothiosemi-carbazones): Synthesis, spectral studies and structural
elucidation
Vinod K Sharma* & Ankita Srivastava
Received 27 November 2006; revised 5 November
2007
Reactions of the ligands, 2,6-diacetylpyridine
bis(S-methylisothiosemicarbazone) and 2,6-diacetylpyridine
bis(S-butylisothiosemicarbazone) with ruthenium(III), rhodium(III) and
iridium(III) have been studied and their structures have been proposed based on
elemental analyses, molar conductance, magnetic moment, spectral data (IR, 1H
NMR, FAB mass) and thermal investigations. The ligands behave as
pentacoordinated and give acyclic complexes of the general formula [M(H2L)Cl2]Cl
and macrocyclic complexes, [M(L’)Cl2]Cl·H2O, which are
formed by template condensation by using β-diketones. Pentagonal
bipyramidal geometries are observed for acyclic and macrocyclic complexes. In
both types of complexes, the ligands coordinate in their amino form. The
thermal stability and mode of decomposition of the various complexes have been
studied by TGA techniques. Conductance measurements reveal 1:1 electrolytic
nature of the complexes.
IPC Code: Int. Cl.8 CO7F15/00
Indian Journal of Chemistry
Vol. 46A, December 2007, pp.
1969-1971
Kinetics and mechanism of visible light
induced oxidation of hydrazine by peroxodisulphate in aqueous solution
containing tris-(2,2¢-bipyridine) ruthenium(II)
Savita Bansal, N K Soni, C L Khandelwal & P D Sharma*
Received 8 December 2006; revised 1 October 2007
The rate of visible light induced oxidation of hydrazine by
peroxodisulphate in the presence of tris-(2,2´-bipyridine)-ruthenium(II)
[Ru(bipy)32+] in aqueous solution is independent of the
substrate concentration but increases with the intensity of light absorbed as
follows:
where ki
is the initial rate and other the terms have their usual meaning.
IPC Code: Int. Cl.8
C07B33/00
Indian Journal of Chemistry
Vol.
46A, December 2007, pp. 1972-1978
Excess transport properties of binary
mixtures of methanol and pyridine through ultrasonic measurements at different
temperatures
G V Rama Rao, A Viswanatha Sarma, D Ramachandran & C
Rambabu*
Received 1 August 2006; revised 3 October 2007
The viscosities, densities and ultrasonic velocities of
binary liquid mixtures of methanol with piperidine and morpholine and pyridine
with piperidine and morpholine have been determined at 303.15 to 318.15K over
the entire composition range. These data have been utilized to estimate the
excess free volume, excess internal pressure, excess enthalpy, excess velocity,
excess acoustic impedance and excess Gibb’s free energy of activation of flow.
The results obtained have been discussed in the light of existing theories of
molecular interaction involved and chemical constitution of the liquid
components. Analysis of these parameters indicates that there are
intermolecular interactions among components of the binary mixtures that lead
to possible hydrogen bond formation (of the type N…H-O) between unlike
molecules.
