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Indian Journal of Chemistry

Sect. A: Inorganic, Bio-inorganic, Physical, Theoretical & Analytical

 

 

     
VOLUME 43 A

NUMBER 1

JANUARY 2004

 

 

 

CONTENTS

 

 

Papers

 1

Equiseparable molecules and molecular graphs

 

  Ivan Gutman*, Boris Furtula, Damir Vukičević, & Biljana Arsić

 

 Equiseparable molecules coincide in many topological properties, implying similar physico-chemical behaviour. A general method for constructing such species is put forward.

 

11

 

 

 Synthesis and characterization of AgBiO3 with the cubic KSbO3 structure

 

Ramesh Sharma, T K Mandal, K Ramesha & J Gopalakrishnan*

 

 

 

 18

Ex-situ high temperature X-ray diffraction studies on partially crystalline conjugated polymers

 A Mani * & K R Ramakrishnan 

 

Molecular and crystalline structural aspects of partially crystalline conjugated polymers have been reported for polyanilines (PANIs) and polythiophene (Pth). Improvement in crystalline order has been observed in chemically synthesized polymers by high-temperature annealing.

 24

 Electronic density of states of copolymers of silole based donor-acceptor polymers: Effect of multi-neighbour interaction

 Geetika Gandhi & A K Bakhshi* 

 

 The effect of multi-neighbour interaction along the copolymer chain on its electronic density of states has been investigated using matrix block negative factor counting method in the case of various periodic and aperiodic copolymers (AmBn)x of the two silole based donor-acceptor polymers PSICO (A)x and PSICN (B)x.

28

 Prediction of excess heat capacity from internal pressure data for n-alkoxyethanol + water mixtures at 298.15 K

 Amalendu Pal* & Harsh Kumar 

 

Excess heat capacities have been reported at 298.15 K for nine binary liquid mixtures of alkoxyethanols with water both from the Prigogine-Flory theory and the internal pressure data. Internal pressure values have been computed on the basis of the statistical thermodynamic theory due to Flory and values of deviation in internal pressure have also been reported.

35

 Partial molar volumes of transfer of some saccharides from water to aqueous cupric chloride and zinc chloride solutions at 298.15K

P K  Banipal*, Gurneet Kaur & T S Banipal

 

Apparent molar volumes of D(-)-arabinose, D(-)-ribose, D(+)-glucose and sucrose in water and in 0.5, 1.0, 2.0 and 4.0 mol kg-1 aqueous cupric chloride and zinc chloride solutions at 298.15 K have been determined from density measurements. Partial molar volumes of transfer Vo2,tr values have been rationalized in terms of solute-cosolute interactions using a cosphere overlap hydration model.

 

 41

A study on viscosities of citric acid and tartaric acid in water and binary aqueous mixtures of ethanol at different temperatures

 M L Parmar*, R K Awasthi & M K Guleria 

 

 Relative viscosities of citric acid and tartaric acid at different concentrations have been determined in water and in binary aqueous mixtures of ethanol at five equidistant temperatures. The data have been evaluated using Jones-Dole equation and the obtained parameters have been interpreted in terms of solute-solute and solute-solvent interactions.

 45

 Adsorption of chromium(VI) ion onto activated amla dust: Adsorption isotherms and kinetics

Krishnamoorthy Anbalagan* & Joseph C Juliet

 

 The adsorption efficiency of amla dust gooseberry in removing chromium(VI) ion from aqueous solution has been investigated in batch experiments. The effects of hexavalent chromium concentration, particle size, adsorbent dosage, temperature and pH have been studied. Removal is found to be most effective at pH 4, low temperature and Cr(VI) ion concentration.

 51

Substituent effects in single helix-double helix interconversions in copper(I) complexes

Michael G B Drew, Shubhamoy Chowdhury & Dipankar Datta* 

 

 

 56

 A convenient synthesis of nickel(II) and cobalt(II) complexes of unsymmetrical salen-type ligands and their application as catalysts for the oxidation of 2,6-dimethylphenol and 1,5-dihy-droxynaphthalene by molecular oxygen

 Waldemar Adam, Chantu R Saha-Moeller & Pralhad A Ganeshpure* 

 

  

 63

Synthesis, X-ray structural characterization and solution studies of a mononuclear Ni(II)-Schiff base complex bearing free formyl groups

 Shankareswar Gupta, Anangamohan Panja, Nizamuddin Shaikh, Sanchita Goswami,
Pradyot Banerjee* & Ray J Butcher
 

 

 

Notes

67

Effect of inorganic electrolytes on the sensing behaviour of polyvinyl alcohol-co-styrene sulphonate as a humidity sensor

 Sang-Do Han*, Ishwar Singh, Young-Ho Jung & Byeong-Kwon Kim 

 

 

71

Synthesis and luminescent properties of Gd2O3:Eu nanocrystalline using EDTA complexing sol-gel process

 Yong-qing Zhai *, Zi-hua Yao, Man-de Qiu,
Bao-sheng Liu & Xiu-lian Dai
 

 

 Gd2O3:Eu nanocrystalline has been synthesized using EDTA complexing sol-gel process at relatively low temperature, in which EDTA and polyethylene glycol have been  used as the chelating and polymerization agents, respectively. The heat decomposion mechanism of the precursor, formation process of Gd2O3:Eu and the properties of the nanocrystalline have been investigated.

 76

Solvation models in the reaction between benzyl bromide and 2-mercapto benzimidazole—A kinetic study

 P Kalyani & P Manikyamba* 

 

The reaction between benzyl bromide and 2-mercapto benzimidazole has been studied in different protic and aprotic solvents. The reaction is first order each in [benzyl bromide] and [2-mercapto benzimidazole]. The product, 2-benzyl mercapto benzimidazole, is proposed to be formed by the proton elimination from the N-H group.

 79

 Oxidative conversion of benzoic and o-chloro-benzoic acid hydrazides to their corresponding acids by thallium(III) : A mechanistic study

 

A R Tardale, A N Phadkule, J B Patil &
G S Gokavi*
 

 

                               

                                      Kc

TlCl2+  +  Hydrazide     Û     Complex 

 Complex    ®        RCONNH + TlCl2-  +2H+                           k1

RCONNH+H2O+ TlCl2 +® RCOOH + N2 + 2H+ + TlCl2-                                         fast

83

 Synthesis and reactivity studies of mononuclear zinc hydroxo complex

 Shalu Tyagi, Chokhe Lal Sharma, Sukh Mahendra Singh & Udai P Singh* 

 

 

 88

 Syntheses and characterization of t(3)-carboxy-ethyl-r(2), c(6)-diphenyl-piperidin-4-one oxime complexes

A Manimekalai* & R Mahendhiran 

 

Non-aromatic heterocyclic ligand, CEDPO, and its complexes [Ni(II), Mg(II), Co(II), Zn(II), Cu(II) and Fe(III)] have been prepared and characterized.

 92

 Synthesis and characterization of transition metal complexes containing oxime, amido and thioamido groups

 A A El-Asmy*, M E Khalifa & M M Hassanian 

 

98

 Synthesis and spectroscopic properties of
3-hydroxy - 3- phenyl-1-o-carboxyphenyltriazene and its copper(II), nickel(II) and zinc(II) complexes

 S Ressalan & C S P Iyer*

 

 

 105

 Synthesis and characterization of 2-t-butyl phenoxotitanium(IV) complexes

 S S Bhatt*, Satinder Jeet, Neeraj Sharma &
S C Chaudhry
 

 

                                 (where n=2 or 3)

 

 

 108

 Solid phase extraction and spectro­photometric determination of silver using
2-(2-quinolinylazo)-5-dimethyl­aminoaniline

 Qiufen Hu, Guangyu Yang*, Zhangjie Huang & Jiayuan Yin  

 

 

 

 111

Spectrophotometric determination of copper(II) in edible oils and seeds using novel oxime– thiosemicarbazones

 K Hussain Reddy* & N B L  Prasad* 

 

Authors for correspondence are indicated by (*)

 

Indian Journal of Chemistry

Vol. 43A, January 2004, pp. 7-10

 

Equiseparable molecules and molecular graphs

Ivan Gutman*, Boris Furtula, Damir Vukičević & Biljana Arsić

 

By deleting an edge ei from the molecular graph G of an acyclic molecule, it decomposes into two fragments, with n1(ei|G) and n2(ei|G) vertices, n1(ei|G) n2(ei|G), i=1,2,...,m. If the edges of the graphs G' and G'', representing two isomeric acyclic molecules, can be chosen so that n1(ei|G') = n1(ei|G'') holds for all i=1,2,...,m, then G' and G'' are said to be equiseparable. The respective two isomeric molecules are also said to be equiseparable. The main (known) physico-chemical consequences of equiseparability are pointed out. A general method for designing pairs of equiseparable molecular graphs is described, by which large sets of equiseparable species can be constructed.

 

 

 

Indian Journal of Chemistry

Vol. 43A, January 2004, pp. 11-17

 

Synthesis and characterization of AgBiO3 with the cubic KSbO3 structure

Ramesh Sharma, T K Mandal, K Ramesha & J Gopalakrishnan*

 

AgBiO3, isotypic with cubic (Im-3 ) KBiO3, has been prepared by K+/Ag+ ion-exchange starting from KBiO3. ⅓H2O. Rietveld refinement of the structure from powder X-ray diffraction data shows that AgBiO3 [a = 9.7852(2) Å; Z = 12; space group Im-3] consists of pairs of edge-shared BiO6 octahedra connected by common corners wherein the Ag+ reside in the tunnels along <111> direction. The BiO6 octahedra are distorted and the average Bi–O bond distance (2.117 Å) is longer than the Bi–O distance (2.099 Å) in the parent. In addition, the Ag(2)–O(2) bond distance (2.429 Å) is considerably short, signaling covalent interaction between Ag+ and BiO3-framework. These structural changes are reflected in the optical properties as well; while the brick red parent shows an absorption edge corresponding to ~ 2 eV band gap, black AgBiO3 shows free carrier absorption in the 400-800 nm range. Similar difference is also seen in the IR spectra.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 18-23

 

Ex-situ high temperature X-ray diffraction studies on partially
crystalline conjugated polymers

A Mani* & K R Ramakrishnan

 

Molecular and crystalline structural aspects of partially crystalline conjugated polymers have been reported for polyanilines (PANis) and polythiophene (Pth). Improvement in crystalline order has been observed in chemically synthesized polymers by high-temperature annealing. This paper mainly concerns structural analysis in terms of degree of crystalline order (Xcr) as the crystalline-gauging parameter, and X-ray diffraction profile data as molecular order probe. A large extent of enhancement of crystalline domains up to 25% through recrystallization and crystallite growth has been obtained by high-temperature annealing of EB-and ES-PANis and Pth-dissociated hexithiophene materials (of intrinsic Xcr = 20 to 50 %). The mechanism of enhancement of crystalline order is given in terms of polymer molecular phenomena.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 24-27

 

Electronic density of states of copolymers of silole based donor-acceptor polymers: Effect of multi-neighbour interaction

Geetika Gandhi & A K Bakhshi*

 

The effect of multi-neighbour interaction along the copolymer chain on its electronic density of states (DOS) has been investigated using matrix block negative factor counting (NFC) method in the case of the various periodic and aperiodic copolymers (AmBn)x of the two silole based donor-acceptor polymers PSICO (A)x and PSICN (B)x. The results obtained are found to be qualitatively similar to those obtained using NFC method in the tight binding approximation implying that as far as the trends in the electronic structures and conduction properties of these copolymers are concerned, they are reasonably well reproduced when interaction up to first neighbour along the copolymer chain only are considered.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 28-34

 

Prediction of excess heat capacity from internal pressure data for n-alkoxyethanol + water mixtures at 298.15 K

Amalendu Pal* & Harsh Kumar

 

Excess heat capacities (CpE) have been determined at 298.15 K for nine binary liquid mixtures of alkoxyethanols with water both from the Prigogine-Flory theory and the internal pressure data. Internal pressure values have been computed on the basis of the statistical thermodynamic theory due to Flory. Values of deviation in internal pressure (DPint) have also been obtained from the data of pure components.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 35-40.  

 

Partial molar volumes of transfer of some saccharides
from water to aqueous cupric chloride and
zinc chloride solutions at 298.15K

P K  Banipal*, Gurneet Kaur & T S Banipal

 

Apparent molar volumes (fv) of three monosaccharides [D(-)-arabinose, D(-)-ribose, D(+)-glucose] and one disaccharide [sucrose] in water and in 0.5, 1.0, 2.0 and 4.0 mol kg-1 aqueous cupric chloride and zinc chloride solutions at 298.15K have been determined from density measurements using a vibrating-tube digital densitymeter. Partial molar volumes (Vo2) at infinite dilution obtained from fv values have been used to calculate partial molar volumes of transfer Vo2,tr for various saccharides from water to aqueous cupric chloride/zinc chloride solutions. Vo2,tr values are positive for all the saccharides studied and increase with increase in concentration of cosolutes. The Vo2,tr values have been rationalized in terms of solute-cosolute interactions using a cosphere overlap hydration model. Pair and triplet interaction coefficients have been calculated using McMillan-Mayer approach and their sign and magnitude have also been discussed.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 41-44

 

A study on viscosities of citric acid and
tartaric acid in water and binary aqueous mixtures of
ethanol at different temperatures

M L Parmar*, R K Awasthi & M K Guleria

 

Relative viscosities of two organic acids viz., citric acid and tartaric acid, at different concentrations have been determined in water and in binary aqueous mixtures of ethanol (5, 10, 15, 20 and 25% by weight of ethanol) at 303K and in water and in 5% (w/w) ethanol + water at five equidistant temperatures. The data have been evaluated using Jones-Dole equation and the obtained parameters have been interpreted in terms of solute-solute and solute-solvent interactions. The activation parameters of viscous flow have been obtained which depicts the mechanism of viscous flow. Both the organic acids behave as structure breakers in water and in binary aqueous mixtures of ethanol.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 45-50

 

Adsorption of chromium(VI) ion onto activated amla dust:
Adsorption isotherms and kinetics

Krishnamoorthy Anbalagan* & Joseph C Juliet

 

The adsorption efficiency of a low cost adsorbent, amla dust (Indian gooseberry, Emblica Officinalis) in removing chromium(VI) ion from aqueous solution has been investigated in batch experiments. The effects of hexavalent chromium concentration, particle size, adsorbent dosage, temperature and pH have been studied. Removal is found to be most effective at pH 4 and at the low temperature and Cr(VI) ion concentration. Therefore, the uptake capacity has been investigated in buffered solutions of pH 4 maintaining a constant ionic strength with 0.01 M NaClO4. The batch adsorption isotherms have been studied in terms of Langmuir and Freundlich isotherm models. Adsorption of Cr(VI) on amla dust is found to follow first order kinetics. The mechanism of Cr(VI) removal on the adsorbent is complex and both the surface adsorption as well as intraparticle diffusion contribute to the rate determining step. Amla dust, the low cost adsorbent is found to be efficient in the removal of Cr(VI) ion in acidic medium, hence, the development of such materials can be applied for the removal of metal ions from industrial waste waters.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 51-55

 

Substituent effects in single helix-double helix
interconversions in copper(I) complexes

Michael G B Drew, Shubhamoy Chowdhury & Dipankar Datta*

 

The copper(I) complex of L, the 1:2 condensate of benzil dihydrazone and 2-formylpyridine, exists as single helical [CuL]+ and double helical [Cu2L2]2+ in dichloromethane solution but crystallizes only as the double helicate [Cu2L2](ClO4)2. In contrast, earlier [New J Chem, 27 (2003) 193] it has been found that with L¢, the 1:2 condensate of benzil dihydrazone and 2-acetylpyridine, only the single helical monomeric species [CuL¢]+ is isolable as solid. This contrasting behaviour of the copper(I) complexes of L and L¢ are scrutinised here by density functional calculations.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 56-62

 

A convenient synthesis of nickel(II) and cobalt(II) complexes of unsymmetrical salen-type ligands and their application as catalysts for the oxidation of 2,6-dimethylphenol and 1,5-dihydroxynaphthalene by molecular oxygen

Waldemar Adam, Chantu R Saha-Moeller & Pralhad A Ganeshpure*

 

Salen-type ligands 1-4 have been synthesized in high yields, from which the nickel(II) complexes 9-11 and the cobalt(II) complexes 12 and 13 have been prepared and characterized. The complexes have been assessed for their ability to activate molecular oxygen in the catalytic oxidation of phenols, namely, 2,6-dimethylphenol and 1,5-dihydroxynaphthalene. The nickel complexes 9-11 are inactive in the oxidation of the phenols but the cobalt complexes 12 and 13 show high catalytic activity.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 63-66

 

Synthesis, X-ray structural characterization and
solution studies of a mononuclear Ni(II)-Schiff base
complex bearing free formyl groups

Shankareswar Gupta, Anangamohan Panja, Nizamuddin Shaikh, Sanchita Goswami, Pradyot Banerjee*

& Ray J Butcher

 

A new mononuclear Ni(II)-Schiff base complex has been synthesized and structurally characterized through X-ray crystallography. The compound crystallizes in the monoclinic space group C2/c (No. 15) with a = 17.268(7), b =14.619(6) and c = 10.683(4) Å. The molecular structure shows that the Ni(II) ion is in the distorted octahedral environment in which two phenolic oxygen atoms occupy the axial positions. Two –CHO groups arising out of the 2,6-diformyl-4-methylphenol remain as pendants. UV/vis and cyclic voltammetric experiments have been performed of the Ni(II) complex in DMF solution and the results compare well with the previously reported systems.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 67-70

 

Effect of inorganic electrolytes on the sensing behaviour of polyvinyl alcohol-co-styrene sulphonate as a humidity sensors

Sang-Do Han*, Ishwar Singh, Young-Ho Jung & Byeong-Kwon Kim

 

Polyvinyl alcohol (PVA), a common hydrophilic polymer shows a significant impedance with changing relative humidity and may be chosen as a base material for humidity sensing devices. However, fabricating simply a polyvinyl alcohol film shows high impedance and lacks durability. Cross-linking PVA with sodium salt of 4-styrene sulphonate (SS) makes the fabricated films water insoluble retaining its humidity sensing capabilities. If PVA and SS are cross-linked in presence of inorganic electrolytes, the sensitivity of the fabricated films as humidity sensors increases tremendously especially in presence of transition metal salts. Mixture of the materials are cured on alumina substrate printed with gold electrodes at a temperature between 120 to 140°C. Taking into concentration the sensitivity and stability of the films both, the best compromising results are obtained when PVA, SS and metal chlorides are taken in a ratio of 5:2:2 for ferrous and ferric and 10:4:3 for cupric and cobalt chlorides.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 71-75

 

Synthesis and luminescent properties of Gd2O3:Eu nanocrystalline using EDTA complexing sol-gel process

Yong-qing Zhai *, Zi-hua Yao, Man-de Qiu, Bao-sheng Liu & Xiu-lian Dai

 

Gd2O3:Eu nanocrystalline has been synthesized using EDTA complexing Sol-Gel process at relative low temperature, in which ethylen-diamine-tetraacetic acid (EDTA) and polyethylene glycol (PEG) were used as the chelating and polymerization agents, respectively. The heat decompose mechanism of the precursor, formation process of Gd2O3:Eu and the properties of the nanocrystalline have been investigated using TG-DTA, XRD, SEM/EDX, Fluorescence spectrophotometer respectively. The results show that pure cubic phase Gd2O3:Eu has been produced after the precursor calcinated only at 700°C for 2h. The particles of the Gd2O3:Eu are basically spherical in shape. The particle size increases from about 30 nm to 100 nm when the calcination temperature increases from 700 to 1000°C. The main emission peak of the sample is at 611 nm, resulting in a red emission. The emission intensity increases with increasing calcination temperature. Compared with micron scale Gd2O3: Eu phosphors prepared by a conventional method, a clear red shift occurs in the excitation spectrum of Gd2O3:Eu nanocrystalline prepared by the present work, the quenching concentration of Eu has been raised.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 76-78

 

Solvation models in the reaction between benzyl bromide and 2-mercapto benzimidazole—A kinetic study

P Kalyani & P Manikyamba*

 

The reaction between benzyl bromide and 2-mercapto benzimidazole has been studied in different protic and aprotic solvents. The reaction is first order each with respect to [benzyl bromide] and [2-mercapto benzimidazole]. Correlation analysis of rate data shows that, the solvent parameters polarity (Y), hydrogen bond donor ability (a), and p* simultaneously influence the rate of the reaction. From the regression analysis, the information about the mode of solvation of the reactants and the transition state is obtained. The product obtained, 2-benzyl mercapto benzimidazole is proposed to form due to the proton elimination from the N-H group.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 79-82

 

Oxidative conversion of benzoic and o-chlorobenzoic acid hydrazides to their corresponding acids by thallium(III) : A mechanistic study

A R Tardale, A N Phadkule, J B Patil & G S Gokavi*

 

The reactions between thallium(III) and benzoic acid and o-chlorobenzoic acid hydrazides have been studied in a mixture of perchloric and hydrochloric acid medium. The reaction involves formation of complex between the reactants, which decompose in the subsequent step to give products. The reaction proceeds by direct two electron transfer without intervention of free radicals. Increase in [H+] and [Cl-] decreases the rate of the reaction. The increase in the ionic strength does not affect the rate of the reaction while decrease in the relative permitivity increases the same. The effect of temperature on the reaction has been studied between 25 to 45oC and the activation parameters were determined for the slow step of the reaction.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 83-87

 

Synthesis and reactivity studies of mononuclear
zinc hydroxo complex

Shalu Tyagi, Chokhe Lal Sharma, Sukh Mahendra Singh & Udai P Singh*

 

The synthesis of mononuclear zinc hydroxo, Zn(OH)(HB(3-But-5-Pripz)3) 2 using sterically hindered pyrazolylborate ligand i.e. hydrotris(3-tert-butyl-5-isopropyl-1-pyrazolyl)borate ligand has been described. The structure of 2 is very similar to the active site of the enzyme carbonic anhydrase. The complex 2 is found to stabilize zinc complexes of uracil and its halo derivatives where uracil and its halo derivatives are bound as monodentate ligand via its deprotonated N1. The halogenated uracil complexes have been injected in Dalton’s Lymphoma tumour system in mice and it is found that Zn[HB(3-But-5-Pripz)3](5-fluorouracilate) exhibits significant antitumour activity. The complex 2 is a very reactive species and is used as catalyst in ester hydrolysis. The complex 2 is also found to promote the hydrolysis of various esters and the maximum rate of hydrolysis is observed with p-nitro­phenylacetate.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 88-91

 

Syntheses and characterization of t(3)-carboxyethyl-r(2), c(6)-diphenyl-piperidin-4-one oxime complexes

A Manimekalai* & R Mahendhiran

 

Complexes of Ni(II), Mg(II), Co(II), Zn(II), Cu(II) and Fe(III) with t(3)-carboxyethyl-r(2),c(6)-diphenylpiperidin-4-one oxime as ligand have been synthesized and the complexes characterised using spectral, magnetic, electrochemical, thermal and elemental analyses. X-ray (powder) diffraction studies reveal that nickel complex crystallizes in tetragonal lattice whereas iron complex crystallizes in monoclinic form.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 92-97

 

Synthesis and characterization of transition metal complexes containing oxime, amido and thioamido groups

A A El-Asmy*, M E Khalifa & M M Hassanian

 

New transition metal complexes of α-oximinoaceto-o-anisidide-4-phenylthiosemicarbazone (H3OAAT) have been prepared and their geometries are assigned. All the investigated complexes are mononuclear except the Cu(II) ions which form binuclear complexes with the chloride and acetate salts. The ligand acts as binegative tridentate in the Co(II), Ni(II), Zn(II) and Pd(II) complexes, trinegative tridentate in the Fe(III) and Co(III) complexes and trinegative pentadentate manner in the Cu(II) complexes. The Cu(II) and Pd(II) complexes possess a square-planar stereochemistry while Ni(II) complex has an octahedral structure. Co(II) salts form diamagnetic and paramagnetic complexes. The protonation constants of the ligand and the stability constants of its Co(II), Ni(II) and Cu(II) complexes are calculated pH-metrically. Moreover, H3OAAT has been applied for the determination of Ni(II), Co(II), Cu(II) and Pd(II) ions in the 0.1-3.5 ppm range.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 98-104

 

Synthesis and spectroscopic properties of 3-hydroxy-3-phenyl-1- o-carboxyphenyltriazene and its copper(II), nickel(II) and zinc(II) complexes

S Ressalan & C S P Iyer*

 

3-Hydroxy-3-phenyl-1-o-carboxyphenyltriazene (HT) is synthesized by coupling diazonium salt of 2-aminobenzoic acid with phenylhydroxylamine in 1:1 molar proportion at 0-5°C. The reagent forms 1:2 metal complexes with Cu(II), Ni(II) and Zn(II) ions in sodium acetate buffer (~pH 5). All these complexes are quite stable in solutions. The reagent and the complexes are characterized by spectral methods viz., UV-vis, FTIR, 1HNMR, 13CNMR and luminescence spectra. The cis- and trans-[Ni(HT)2]0 complexes have been separated and determined by 1HNMR technique. The L®M and M®L charge transfer character of the complexes is also studied by 1HNMR technique. The mechanism of excited state electron transfer and energy transfer of the ligand has been investigated to explain the formation of tautomeric isomers of HT which led to the application of these donor-acceptor systems in molecular electronics.

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 105-107

 

Synthesis and characterization of 2-t-butyl phenoxotitanium(IV) complexes

S S Bhatt*, Satinder Jeet, Neeraj Sharma & S C Chaudhry

 

Complexes of composition TiCl4-n(OC6H4-But-2)n (where n =1 to 4 and OAr = OC6H4-But-2) have been prepared by the reaction of titanium(IV) chloride with Me3SiOAr in predetermined molar ratios in carbon tetrachloride/toluene as solvent These complexes have been characterized by elemental, IR, 1H NMR and TG analysis and molecular weight determinations. Lewis acid character of the complexes has also been established by isolating adducts with some monodentate aliphatic amines and bidentate aromatic amines.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 108-110

 

Solid phase extraction and spectro­photometric determination of silver using 2-(2-quinolinylazo)-5-dimethyl­aminoaniline

Qiufen Hu , Guangyu Yang *, Zhangjie Huang  & Jiayuan Yin

A new method for the determination of silver based on the rapid reaction of silver(I) with 2-(2-quinolinylazo)-5-dimethyl­aminoaniline (QADMAA) and the solid phase extraction of the coloured chelate was developed. The QADMAA reacts with silver to form a violet chelate with molar ratio 1:2 (silver to QADMAA) in the buffer solution of pH=6.5 and SDS medium. This chelate is enriched by solid phase extraction with C18 cartridge and a high enrichment factor is achieved. The molar absorptivity of the complex is 1.25´105 L mol-1 cm-1 at 585 nm, and Beer’s law is obeyed in the range of 0.01~0.6 mg ml-1. This method is applied for the determination of silver in natural water with good results.

 

 

 

Indian Journal of Chemistry 

Vol. 43A, January 2004, pp. 111-114

 

Spectrophotometric determination of copper(II) in edible oils and seeds using novel oxime-thiosemicarbazones

K Hussain Reddy* & N B L Prasad

 

Benil-a-monoxime thiosemicarbazone (BMOT) and 1-phenyl-1,2-propane dione-2-oxime thiosemicarbazone (PPDOT), a novel class of oxime thiosemicarbazones have been synthesized and characterized using IR, NMR and mass spectral data. PPDOT has been used for the spectrophotometric determination of copper(II). The reagents give yellow colour with copper(II) in sodium acetate acetic acid buffers. The molar absorptivity and Sandell’s sensitivity of Cu-BMOT and Cu-PPDOT are 2.2´104 and 0.58´104 L mol-1 cm-1 at 355 and 465 nm and 0.0029 and 0.0110 mg cm-2, respectively. This method is successfully applied for determination of Cu(II) in edible oils and seeds.