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Indian Journal of Chemistry

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

 

 

 

VOLUME 43A

NUMBER 11

NOVEMBER 2004

 

CONTENTS

 

Papers

2265

 Differential encapsulation of pyrene-end-capped poly (ethyleneoxide) by cyclodextrins in aqueous solutions. A fluorometric study

  

 

 

Basudeb Haldar, Arabinda Mallick,  Pradipta Purkayastha, Hugh D Burrows & Nitin Chattopadhyay*

 

 

 The photophysical behavior of pyrene-end-capped poly(ethyleneoxide) (PYPY) has been studied in water and aqueous a-, b- and g-cyclodextrin (CD) environments through steady-state and time-resolved spectroscopy.

 

2274

Novel 16-membered [N6] macrocycles bearing hexaamide functions and their metal-encapsulated compounds

 

Zafar Ahmad Siddiqi*&  Shah Mohammad Shadab

 

 

A pendant armed hexaaza macrocycle with hexaamide functions, its substituted analogue which is a mimic to synthetic cyclic hexapeptide, and their reactivities towards metallic substrates are reported.

 

2281

NMR studies of styrene/n-butyl acrylate copolymers prepared by atom transfer radical polymerization

 

 

 

 

 

 

A S Brar* & Puneeta

 

 

Styrene and n-butyl acrylate have been copolymerized by atom transfer radical copolymerization catalyzed by CuBr/N,N,N′,N′,N″-pentamethyldiethylenetriamine. The copolymer composition data has been used to determine the reactivity ratios by Kelen-Tudos and nonlinear error in variables methods. Molecular weights of the copolymers increase with increase in percentage conversion. The polydispersity of the copolymers is quite low (1.1-1.3). Styrene and n-butyl acrylate centered triads concentrations have been determined from 13C{1H} NMR and reactivity ratios.

2287

 o-Diphenylphosphinobenzaldehyde complexes of palladium(II) and platinum(II): Synthesis, spectroscopy and structure

 

    

 

 

H Mahalakshmi, Prasad P Phadnis, Vimal K Jain* & Edward R T Tiekink*

 

 

 

2294

Synthesis and structure studies of Co(II), Ni(II), Cu(II), Pd(II), Ru(II), Ag(I), Cd(II) and dioxouranium(VI) complexes with 1-acetoacet-o-toluidide-4-phenyl-3-thiosemicarbazone

 

 

Kamal M Ibrahim, Sahar I Mostafa*, Nagwa Nawar & Zeinab A Younis

 

 

 

2301

Synthesis and characterization of organotin(IV) compounds with Schiff base ligand pyruvic acid isonicotinyl hydrazone and crystal structure of [n-Bu2Sn(C9H8N3O3)(H2O)]2 and {[n-Bu2Sn-(C9H8N3O3)O]Sn(Bu-n)3}2.2H2O

 

 

Han Dong Yin*, Min Hong & Qi Bao Wang

 

 

 

2307

Kinetics and mechanism of pentacyanohydroxo-ferrate(III) formation from the reaction of [FeL(OH)]2-n complexes with cyanide ions
[Ln- = trans-1,2-diaminocyclohexane-tetraacetic acid (CYDTA) and nitilotriacetic acid (NTA)]

 

 

 

 

 

Radhey M Naik*, Desh D Chaturvedi, Neena Srivastava, Amit K Verma, Anjani K Tewari & Abhinav Agarwal

 

 

 The kinetics and mechanism of exchange of CYDTA4- in [FeCYDTA (OH)]2- and NTA3- in [FeNTA(OH)]1- with cyanide ions (CYDTA4- = trans-1,2-diaminocyclohexanetetraacetic acid and NTA = nitrilotriacetic acid) have been investigated spectrophotometrically. Both the reactions exhibit three observable stages leading to the formation of [Fe(CN)5OH]3-, [Fe(CN)6]3- and [Fe(CN)6]4- respectively. A five step mechanistic scheme is proposed for both the systems in their first stage of reaction involving the presence of four cyanide ions around the central iron atom in the rate determining step. A linear free energy relationship has been proposed between stepwise rate constants and the overall stability constants of the mixed ligand complexes of the type [FeL(OH)(CN)­5­OH]2-n-x formed in a particular step.

Notes

2315

Synthesis and characterization of a novel composite macroporous titanoaluminophosphate molecular sieve, NCL-9

 

 

 

 

 

 

 

 

N Venkatathri

 

 

A novel composite macroporous titanoaluminophosphate molecular sieve, NCL-9, is synthesized and characterised. XRD, TEM and surface area analysis show the presence of macroporous regions along with other porous regions. However, on heating the microporous region is converted to dense phases, which may be avoided by H2O2 treatment. SEM analysis shows the sample present as flags with 30 x 15 mm particle size. TG/DTA shows 35.38% weight loss which is confirmed by C and N analysis. UV-vis and XPS data show the presence of Ti in tetrahedral co-ordination. 27Al and 31P MAS NMR spectra show characteristic peaks for tetrahedral coordination, along with a small amount of octahedral aluminium.

2320

Selective oxidation of propane to acrolein over different Mo-V-Te-P-O catalysts

 

 

  

 

 

Huachang Jiang, Weimin Lu* & Huilin Wan

 

A series of multicomponent catalysts with different amount of Mo, V, Te and P have been prepared and applied for selective oxidation of propane to acrolein. (V0.07Mo0.93)5O14 is one of the key phases which are in favor of the formation of acrolein from partial oxidation of propane and its intensity is seriously affected by the component of the catalyst. The catalyst, MoV0.3Te0.23P0.15On, shows the best performance with respect to conversion of propane (46.6%) and the selectivity of acrolein (47.0%).

 

2325

Catalytic and electrocatalytic oxidation of toluene over vanadium aluminophosphate molecular sieves: VAPO-5 using H2O2 and t-butyl hydroperoxide as oxidant

 

 

 

 

 

N Venkatathri

 

 

A comparison of the results of catalytic and electrocatalytic oxidation of toluene using VAPO-5 in the presence of H2O2 and TBHP indicates remarkable differences in conversion and selectivity. VAPO-5 catalyzes the oxidation of toluene selectively to benzoic acid (70%) in the presence of t-butyl hydroperoxide (TBHP), while benzaldehyde (48%) is formed selectively when H2O2 is used. Cyclic voltammetric studies show a three step oxidation of toluene to oxidized product in TBHP and two step oxidation of toluene in H2O2.

 2329

DNA hydrolytic cleavage by stable Zn(II) dipeptide complexes

 

 

 

 

 

Pulimamidi Rabindra Reddy*, Sepuru Krishna Mohan & Kandibanda Srinivasa Rao

 

 

 

2333

Oxygen reduction by FeN4 – A DFT study

 

Ch Venkateswara Rao & B Viswanathan*

 

 

 DFT calculations have been performed to study the electrocatalytic activity of FeN4 for the reduction of O2. This study shows that the same symmetry, energy and directional nature of the HOMO of FeN4 with that of the p* orbital of O2 initiates and facilitates its reduction.

2336

Effect on phase diagrams in the binary mixtures of the series of 4-n-alkyloxy phenyl-4’-n-alkyl cyclohexyl carboxylate with different meso phases

 

Aradhana Anand, R K  Bamezai* & N K Sharma

 

 

Various binary diagrams of state have been studied in order to study the influence of  nematic phase and smectic A phase and nematic phase with different homologous series of 4-n-alkyloxy phenyl-4’-n-alkyl cyclohexyl carboxylate (D-nOm). Smectic A phase has either been induced or its region of existence enhanced in specific concentration regions.

2340

Electrocatalysis of polished glassy carbon electrode with silicon carbide abrasive paper for the oxidation of adrenaline

  

Zhang-Yu Yu*, De-Sheng Kong *, Shu-Xin Wu, Tao Liu & Han-Qing Wang

 

 

The electrocatalytic properties of the SiC particle-modified glassy carbon (MGC) electrode, have been studied by cyclic voltammetry for adrenaline oxidatio. It has been found that compared to bare glass carbon electrode, the peak current (ip) increases and the peak-to-peak potential separation (DEp) decreases significantly on MGC. This has been attributed to the presence of the SiC particles adhered to GC surface.

2343

Two-dimensional 18-crown-6 complex, [Na2(18-C-6)2(H2O)3]-[Ni(dmit)2]2·(18-C-6), assembled by S···S and Ni·S weak interactions

 

 

 

  

 

 

Guofang He, Daqi Wang, Jianmin Dou* & Dacheng Li

 

 

 

2347

Synthesis, characterization and structural studies on metal complexes derived from bezofuran thiosemicarbazide ligands

 

 

Madappa B Halli* & Zhahiruddin S Qureshi

 

 

The complexes of the type MLXn, where M = Co(II), Cu(II), Ni(II), Cd(II), Hg(II), Zn(II), UO2(VI) and Th(IV), X= Cl/NO3, n = 2/4, and L is the thiosemicarbazide ligand derived from reaction between benzofuran-2-carboxyhydrazide and phenylisothiocynate/ p-chlorophenylisothiocynate. The thiosemicarbazide ligands and their metal complexes have been screened for their antimicrobial activity.

2352

Synthesis and characterization of some iron(III) complexes containing 4-benzyloxybenzoylhydra-zones.

 

 

  

 

 

 

 

 

M B H Howlader* & M S Begum

 

 

 

 

Iron(III) complexes [(CH5CH2OC6H4C=N-N=CHR)2], where R = H; CH3; CH3CH=CH; C6H5; CH3OC6H4; ClC6H4; C6H5CH=CH and C6H5CH2OC6H4, are formed when 4-benzyloxybenzoylhydrazine and aldehydes (such as formalde-hyde, acetaldehyde, crotonaldehyde, 4-methoxybenzaldehyde, 4-chlorobenzaldehyde, cinnam-aldehyde and 4-benzyloxybenzalde-hyde) react with iron(III) chloride. The complexation proceeds through the formation of intermediate carbohydrazone ligand, and not the template condensation process.

2357

Synthesis and physico-chemical characterization of a new Mannich base, N-(morpholino-benzyl) benzamide and its Cu(II), Co(II), Ni(II) and Zn(II) complexes

 

N Raman*, R Vimalaramani &
C Thangaraja

 

 

 

2361

Studies on PVC-based chelating inorganic ion exchange resin membrane sensor for neodymium(III) ion

 

 

 

 

Himanshu Agarwal & Sulekh Chandra*

 

A PVC-based sensor for Nd3+ ions based on chelating inorganic ion exchange resin [tetracycline-sorbed zirconium(IV) tungstophosphate (TC-ZWP)] as an electroactive material has been prepared. The proposed membrane sensor reveals good selectivity for Nd3+ with regard to other trivalent lanthanide metal ions and could be used in the pH range 3-7, as well as in the partially non-aqueous media. The sensor has also been successfully used as an indicator electrode in the potentiometric titration of Nd3+ against EDTA.

 

Authors for correspondence are indicated by (*)

 

 

 

Indian Journal of Chemistry

 Vol. 43A, November 2004, pp. 2265-2273

 

Differential encapsulation of pyrene-end-capped poly(ethyleneoxide) by cyclodextrins in aqueous solutions. A fluorometric study

Basudeb Haldar, Arabinda Mallick, Pradipta Purkayastha, Hugh D Burrows & Nitin Chattopadhyay*

 

The photophysical behavior of pyrene-end-capped poly(ethylene oxide) (PYPY) has been studied in water and aqueous a-, b- and g-cyclodextrin (CD) environments through steady-state and time-resolved spectroscopy. Both absorption and fluorometric studies reveal that a-, b- and g-CD interact differently with the fluorophore. While PYPY forms 1:1 inclusion complexes with b- and g-CD as reflected from the presence of isosbestic points in the absorption spectra and isoemissive points in the fluorescence spectra, it does not show similar complexation with a-CD. The emission spectrum of PYPY in aqueous solution shows characteristic dual emission; with a structured band assigned to the pyrene monomer emission and a broad and unstructured one at lower energy assigned to the excimer emission. Addition of b- or g-CD to the aqueous solution of PYPY modifies the fluorescence spectrum markedly. In b-CD solution, the excimer emission yield is reduced with a concomitant enhancement of the monomer emission while in g-CD solution the excimer emission increases at the cost of the other band. The differences in photophysical behavior of the fluorophore in different CD environments are explained in the light of different modes of encapsulation of PYPY in CDs with different cavity dimensions. The present study points to the probable location of the probe within the microheterogeneous environment. The relevance of these results to the use of cyclodextrins in modulating the aggregation behavior of hydrophobically end-capped poly(ethyleneoxide)s is discussed.

 

 

 

Indian Journal of Chemistry

 Vol. 43A, November 2004, pp. 2274-2280

 

Novel 16-membered [N6] macrocycles bearing hexaamide functions and their metal-encapsulated compounds

Zafar Ahmad Siddiqi* & Shah Mohammad Shadab

 

Cyclocondensation reaction between phthalic anhydride or phthalic acid and semicarbazide hydrochloride in DMF-methanol under reflux affords colourless crystalline solid (L1) characterized as a [2+2] macrocycle possessing hexaamide functions, with succinic anhydride or succinic acid the reaction is feasible in presence of excess HCl giving the salt (L2×2HCl) of the macrocycle. Reactions of the macrocycles with MCl2 or [M(PPh3)2Cl2] (M = Zn, Cd or Hg), result in complexes having M:L=1:1 stoichiometry with MLCl2 composition. Physico-chemical and spectroscopic investigations of complexes reveal that proton at aza group (NH) of the amide/peptide function does not deprotonate prior to coordination and hexacoordination around metal ions is maintained.

 

 

 

Indian Journal of Chemistry

Vol. 43A, November 2004, pp. 2281-2286

 

NMR studies of styrene/n-butyl acrylate copolymers prepared by atom transfer radical polymerization

A S Brar* & Puneeta

 

Styrene (S) and n-butyl acrylate (B) have been copolymerized by atom transfer radical copolymerization (ATRP) catalyzed by CuBr/N,N,N′,N′,N″-pentamethyldiethylenetriamine. The composition of copolymers has been determined with 1H NMR spectroscopy. The copolymer composition data has been used to determine the reactivity ratios by Kelen-Tudos (KT) and nonlinear error in variables methods (EVM). Molecular weights of the copolymers have been determined by gel permeation chromatography (GPC). Molecular weights of the copolymers increase with increase in percentage conversion. The polydispersity of the copolymers is quite low (1.1-1.3). Styrene and n-butyl acrylate centered triads concentrations have been determined from 13C{1H} NMR and reactivity ratios and show good agreement with each other.

 

 

 

Indian Journal of Chemistry

Vol. 43A, November 2004, pp. 2287-2293

 

o-Diphenylphosphinobenzaldehyde complexes of palladium(II) and platinum(II): Synthesis, spectroscopy and structure

H Mahalakshmi, Prasad P Phadnis, Vimal K Jain* & Edward R T Tiekink*

 

Preparation of the o-diphenylphosphinobenzaldehyde complexes of Pd(II) and Pt(II), with general formulae [MX2L2], [Pd2Me2(µ-Cl)2L2] and [PdMeClL2] where [M = Pd or Pt; X = Cl, Br, I and L = o-diphenylphosphinobenzaldehyde, {PPh2(o-C6H4CHO)}], is reported here. All complexes have been characterized by elemental analysis, IR, NMR (1H, 13C, 31P and 195Pt) and UV-visible spectroscopy, that allowed the deduction of the stereochemistry for the complexes. The mononuclear complexes have been found to adopt the trans configuration in square-planar geometries. The molecular structure of trans-[PdCl2{PPh2(C6H4CHO)}2] has been established by a single crystal X-ray diffraction study and confirms the spectroscopic conclusions.

 

 

 

Indian Journal of Chemistry

Vol. 43A, November 2004, pp. 2294-2300

 

Synthesis and structure studies of Co(II), Ni(II), Cu(II), Pd(II), Ru(II), Ag(I), Cd(II) and dioxouranium(VI) complexes with 1-acetoacet-o-toluidide-4-phenyl-3-thiosemicarbazone

Kamal M Ibrahim, Sahar I Mostafa*, Nagwa Nawar & Zeinab A Younis

 

The synthesis of the new 1-acetoacet-o-toluidide-4-phenyl-3-thiosemicarbazone (H2aatpt) complexes; [M(Haatpt)2(H2O)n] (M(II) = Co, Cd, n = 0; M(II) = Ni, Cu, n = 2), [Cu(Haatpt)(AcO)(H2O)2], [M(Haatpt)2Cl(H2O)n] (M (II) = Cu, n = 0; M(II) = Ru, n = 2), [Pd(H2aatpt)Cl2], [Ag(H2aatpt)(H2O)2]NO3 and trans-[UO2(Haatpt)2] is reported. Their elemental analyses, molar conductivities, thermal, magnetic measurements, IR, 1H NMR and UV-vis spectroscopy have been investigated. Growth inhibition of B. subtilis and Micrococcus sp. by H2aatpt and its Ni(II) and Pd(II) complexes is reported.

 

 

 

Indian Journal of Chemistry

 Vol. 43A, November 2004, pp. 2301-2306

 

Synthesis and characterization of organotin(IV) compounds with Schiff base ligand pyruvic acid isonicotinyl hydrazone and crystal structure of [n-Bu2Sn(C9H8N3O3)(H2O)]2 and
{[n-Bu2Sn(C9H8N3O3)O]Sn(Bu-n)3}2.2H2O

Han Dong Yin*, Min Hong & Qi Bao Wang

 

The organotin(IV) compounds [n-Bu2Sn(C9H8N3O3)(H2O)]2 (1) and {[R2Sn(C9H8N3O3)O]SnR3}2 [R=n-Bu (2), 4-CN-C6H4CH2 (3), C6H5CH2 (4)] were prepared by the reaction of Schiff base ligand pyruvic acid isonicotinyl hydrazone with n-Bu2SnO or (R3Sn)2O in the corresponding molar ratio of 1:1 and 1:2. All compounds have been characterized by elemental analysis, IR and 1H NMR spectra. The crystal structures of compounds 1 and 2 were determined by X-ray single crystal diffraction analysis. The crystal 1 belongs to orthorhombic with space group Pca2(1), a=2.7529(18) nm, b=0.9668(7) nm, c=1.5750(11) nm, α=90º, β=90º, γ=90º, Z=8, V=4.192(5) nm3, Dc=1.445 g/cm3, μ=1.243 mm–1, F(000)=1856, R=0.0493, wR=0.1066, and its structure shows a distorted pentagonal bipyramid geometry with seven-coordination for the central tin atom. The crystal 2 belongs to monoclinic with space group P2(1)/c, a=1.4811(16) nm, b=1.3788(15) nm, c=1.923(2) nm, β=99.848(19)º, Z=2, V=3.869(7) nm3, Dc=1.309 g/cm3, μ=1.324 mm-1, F(000)=1556, R=0.0622, wR=0.1403, and it exhibits a dimeric structure containing distannoxane units with two types of tin atoms. For the first tin atom, it appears to be seven-coordinated with distorted pentagonal bipyramid geometry, and the other is five-coordinated with distorted trigonal bipyramidal geometry. Also, the Schiff base ligand pyruvic acid isonicotinyl hydrazone is found to function as trident chelates with O, N and O atoms.

 

 

 

Indian Journal of Chemistry

Vol. 43A, November 2004, pp. 2307-2314

 

Kinetics and mechanism of pentacyanohydroxoferrate(III) formation from the reaction of [FeL(OH)]2-n complexes with cyanide ions [Ln- =trans-1,2-diaminocyclohexanetetraacetic acid (CYDTA) and nitrilotriacetic acid (NTA)]

Radhey M Naik*, Desh D Chaturvedi, Neena Srivastava, Amit K Verma, Anjani K Tewari & Abhinav Agarwal

 

The kinetics and mechanism of exchange of CYDTA4- in [FeCYDTA (OH)]2- and NTA3- in [FeNTA(OH)]1- with cyanide ions (CYDTA4- = trans-1,2-diaminocyclohexanetetraacetic acid and NTA = nitrilotriacetic acid) have been investigated spectrophotometrically at 395 nm (lmax of [Fe(CN)5OH]3-) under the conditions, temp. = 45 + 0.1oC, pH = 11+0.02 and I= 0.25 M(NaClO4) for CYDTA and temp. 25+0.1oC, pH =9.0 + 0.02 and I=0.4 M (NaClO4) for NTA. Both the reactions exhibit three observable stages leading to the formation of [Fe(CN)5OH]3-, [Fe(CN)6]3- and [Fe(CN)6]4- respectively. The [FeCYDT(OH)]2--CN- as well as [FeNTA(OH)]1--CN- systems show variable order dependences in [CN-] in their first stage, ranging from one to two and zero to one at low and high cyanide concentrations. The second stage of reaction is common for both the systems and follow a first order dependence each in [Fe(CN)5OH3-] and [CN-]. The third stage of reaction follows a overall second order kinetics, first order each in [Fe(CN)5OH3-] and [Ln-] (Ln- = CYDTA4- and NTA3-). The thermodynamically unfavourable reverse reaction of [Fe(CN)5OH]3- with [CYDTA]4- and [NTA]3- have also been studied under forcing conditions by taking large excess of [CYDTA]4- and [NTA]3-. These reactions exhibit first order dependence each in [Fe(CN)5OH3-] and [CYDTA4-] or [NTA3-] and an inverse first order dependence in [CN-] which makes it possible to identify the fourth step as rate determining one. The dependence of forward rate on ionic strength also confirms that the fourth step is rate determining in the porposed reaction mechanism for the first stage of reaction. A five step mechanistic scheme is proposed for both the systems in their first stage of reaction involving the presence of four cyanide ions around the central iron atom in the rate determining step. The activation parameters for both forward and backward reactions of the first stage of reaction are evaluated and they support the proposed mechanism.

 

 

 

Indian Journal of Chemistry

Vol. 43A, November 2004, pp. 2315-2319

 

Synthesis and characterization of a novel composite macroporous titanoaluminophosphate molecular sieve, NCL-9

N Venkatathri

 

A novel composite macroporous titanoaluminophosphate molecular sieve, NCL-9, is synthesized and characterised. XRD, TEM and surface area analysis show the presence of macroporous regions along with other porous regions. However, on heating the microporous region is converted to dense phases, which may be avoided by H2O2 treatment. SEM analysis shows the sample present as flags with 30 ´ 15 mm particle size. TG/DTA shows 35.38% weight loss which is confirmed by C and N analysis. FT-IR spectra show bands similar to other known aluminophosphates. A band at 916 cm-1 for Al-O-Ti bond is observed. UV-vis and XPS data show the presence of Ti in tetrahedral co-ordination. 27Al and 31P MAS NMR spectra show characteristic peaks for tetrahedral coordination, along with a small amount of octahedral aluminium.

 

 

 

Indian Journal of Chemistry

Vol. 43A, November 2004, pp. 2320-2324

 

Selective oxidation of propane to acrolein over different Mo-V-Te-P-O catalysts

Huachang Jiang, Weimin Lu* & Huilin Wan

 

A series of multicomponent catalysts with different amount of Mo, V, Te and P have been prepared and applied for selective oxidation of propane to acrolein. (V0.07Mo0.93)5O14 is one of the key phases which is in favour of the formation of acrolein from partial oxidation of propane and its intensity is seriously affected by the component of the catalyst. The catalyst, MoV0.3Te0.23P0.15On, shows the best performance with respect to conversion of propane (46.6%) and the selectivity of acrolein (47.0%).

 

 

 

Indian Journal of Chemistry

Vol. 43A, November 2004, pp. 2325-2328

 

Catalytic and electrocatalytic oxidation of toluene over vanadium aluminophosphate molecular sieves: VAPO-5 using H2O2 and t-butyl hydroperoxide as oxidant

N Venkatathri

 

A comparison of the results of catalytic and electrocatalytic oxidation of toluene using VAPO-5 in the presence of H2O2 and TBHP indicates remarkable differences in conversion and selectivity. VAPO-5 catalyzes the oxidation of toluene selectively to benzoic acid (70%) in the presence of t-butyl hydroperoxide (TBHP), while benzaldehyde (48%) is formed selectively when H2O2 is used. Cyclic voltammetric studies show a three step oxidation of toluene to oxidized product in TBHP and two step oxidation of toluene in H2O2. Electrocatalytic oxidation of toluene to oxidized products occurs at a potential 800 mV less than that corresponding to H2O2 as oxidant. The enhancement of electrocatalytic rate is attributed to the stabilization of electron deficient transition state.

 

 

 

Indian Journal of Chemistry

 Vol. 43A, November 2004, pp. 2329-2332

 

DNA hydrolytic cleavage by stable Zn(II) dipeptide complexes

Pulimamidi Rabindra Reddy*, Sepuru Krishna Mohan & Kandibanda Srinivasa Rao

 

Interaction of zinc with dipeptides cysteinylglycine, histidylphenylalanine and histidylserine has been investigated at 35oC and 0.1 M ionic strength and the stabilities of these complexes determined. The binding modes and the geometry have been established with the help of pH metry and 1H NMR and UV visible spectra. The DNA binding and cleavage abilities of these zinc dipeptide complexes have been probed. The results demonstrate the efficiency of these complexes in the DNA cleavage.

 

 

 

Indian Journal of Chemistry

 Vol. 43A, November 2004, pp. 2333-2335

 

Oxygen reduction by FeN4 – A DFT study

Ch Venkateswara Rao & B Viswanathan*

 

DFT calculations have been performed to study the electrocatalytic activity of FeN4 for the reduction of O2. This study shows that the same symmetry, energy and directional nature of the HOMO of FeN4 with that of the p* orbital of O2 initiates and facilitates its reduction.

 

 

 

Indian Journal of Chemistry

Vol. 43A, November 2004, pp. 2336-2339

 

Effect on phase diagrams in the binary mixtures of the series of 4-n-alkyloxy phenyl-4¢-n-alkyl cyclohexyl carboxylate with different meso phases

Aradhana Anand, R K  Bamezai* & N K Sharma

 

Various binary diagrams of state have been studied in order to study the influence of  nematic phase and smectic A phase and nematic phase with different homologous series of 4-n-alkyloxy phenyl-4¢-n-alkyl cyclohexyl carboxylate (D-nOm). Smectic A phase has either been induced or enhanced its region of existence in specific concentration regions.

 

 

 

Indian Journal of Chemistry

 Vol. 43A, November 2004, pp. 2340-2342

 

Electrocatalysis of polished glassy carbon electrode with silicon carbide abrasive paper for the oxidation of adrenaline

Zhang-Yu Yu*, De-Sheng Kong *, Shu-Xin Wu, Tao Liu & Han-Qing Wang

 

The electrocatalytic properties of the SiC particle-modified glassy carbon (MGC) electrode, prepared by polishing on a silicon carbide abrasive paper, have been studied by cyclic voltammetry for adrenaline oxidation in a McIlvaine buffer solution and in 0.5 mol dm-3 H2SO4. It has been found that compared to bare glass carbon (GC) electrode, the peak current (ip) increases and the peak-to-peak potential separation (DEp) decreases significantly on MGC. This has been attributed to the presence of the SiC particles adhered to GC surface, since further ultrasonication treatment of MGC, which can induce the SiC particles to fall off from the surface, results in a decrease in ip and an increase in DEp.

 

 

 

Indian Journal of Chemistry

 Vol. 43A, November 2004, pp. 2343-2346

 

Two-dimensional 18-crown-6 complex, [Na2(18-C-6)2(H2O)3]-[Ni(dmit)2]2·(18-C-6), assembled by S···S and Ni···S weak interactions

Guofang He, Daqi Wang, Jianmin Dou* & Dacheng Li

 

A novel two-dimensional 18-crown-6 (18-C-6) complex, [Na2(18-C-6)2(H2O)3][Ni(dmit)2]2·(18-C-6) (dmit, 4,5-dimercapto-1,3-dithiole-2-thione, C3S52-) (1) has been synthesized and characterized by elemental analysis, IR spectrum and X-ray diffraction analysis. 1 belongs to triclinic, space group P-1 with cell dimensions, a = 13.227(10), b = 12.8421(11), c = 13.8671(12) Å, a = 83.715(2), b = 88.477(2), g = 71.850(2)°, V = 1904.5(3) Å 3, Z = 2, Dcalcd = 1.566 g/cm3, F(000) = 932, R1 = 0.0415, wR2 = 0.0805. It consists of one [Na2(18-C-6)2(H2O)3]2+ complex cation, two [Ni(dmit)2]- complex anions and one free 18-C-6 molecule. The complex shows two-dimensional structure assembled by S···S and Ni···S weak interactions.

 

 

 

Indian Journal of Chemistry

Vol. 43A, November 2004, pp. 2347-2351

 

Synthesis, characterization and structural studies on metal complexes derived from benzofuran thiosemicarbazide ligands

Madappa B Halli* & Zhahiruddin S Qureshi

 

The complexes of the type MLXn, where M = Co(II), Cu(II), Ni(II), Cd(II), Hg(II), Zn(II), UO2(VI) and Th(IV), X= Cl/NO3 , n = 2/4, and L is the thiosemicarbazide ligand derived from reaction between benzofuran-2-carboxyhydrazide and phenylisothiocyanate (BCPT)/p-chlorophenyliso­thiocyanate (BCClPT). All the complexes isolated in solid state, are stable in air and characterized by the elemental analysis, IR, electronic spectral data, magnetic moment and conductance measurement studies. Thiosemicarbazide ligands behave as bidentate by coordinating through oxygen of carbonyl group and nitrogen of hydrazine residue. The probable structure for all the metal complexes is also proposed here. The thiosemicarbazide ligands and their metal complexes have been screened for their antimicrobial activity.

 

 

 

Indian Journal of Chemistry

Vol. 43A, November 2004, pp. 2352-2356

 

Synthesis and characterization of some iron(III) complexes containing
4-benzyloxybenzoylhydrazones

 

M B H Howlader* & M S Begum

 

Iron(III) complexes [(CH5CH2OC6H4C=N-N=CHR)2], where R = H, 3; CH3, 4; CH3CH=CH, 5; C6H5, 6; CH3OC6H4, 7; ClC6H4, 8; C6H5CH=CH, 9 and C6H5CH2OC6H4, 10 are formed when 4-benzyloxybenzoylhydrazine 1 and aldehydes (such as formalde-hyde, acetaldehyde, crotonaldehyde, 4-methoxybenzaldehyde, 4-chlorobenzaldehyde, cinnamaldehyde and 4-benzyloxybenzalde-hyde) react with iron(III) chloride. The complexation proceeds through the formation of intermediate carbohydrazone ligand 2, not the template condensation process. The carbohydrazone ligand coordinate to the metal via the deprotonation of enol form. The complexes have been characterized by elemental analyses, conductance and magnetic moment measurements, UV-visible, infrared and mass spectroscopic studies. The complexes are found to be paramagnetic but do not show any liquid crystalline behaviour, instead they decompose during melting stage.

 

 

 

Indian Journal of Chemistry

 Vol. 43A, November 2004, pp. 2357-2360

 

Synthesis and physico-chemical characterization of a new Mannich base,
N-(morpholinobenzyl)benzamide and its Cu(II), Co(II), Ni(II) and  Zn(II) complexes

N Raman*, R Vimalaramani & C Thangaraja

 

A new Mannich base, N-(morpholinobenzyl)benzamide (MBB), formed by the condensation of morpholine, benzamide and benzaldehyde and its Cu(II), Co(II), Ni(II) and Zn(II) complexes have been synthesized. Their probable structures have been determined on the basis of their microanalytical, IR, UV-vis, 1H NMR, 13C NMR and FAB-mass spectral data. All the complexes exhibit square planar geometry. The monomeric and non-electrolytic nature of the complexes are evidenced by their magnetic susceptibility and low conductance data. The electrochemical behaviour of the complexes in acetonitrile solution has been studied by cyclic voltammetric method. The biological activities of the ligand and its metal chelates against the bacteria E.coli, Staphylococcus aureus, Klebsiella pneumoniae, Salmonella typhi, Pseudomonas aeruginosa and Shigella flexnri are also reported. The complexes have higher activity than that of the free Mannich base and the control.

 

 

 

Indian Journal of Chemistry

Vol. 43A, November 2004, pp. 2361-2364

 

Studies on PVC-based chelating inorganic ion exchange resin membrane sensor for neodymium(III) ion

Himanshu Agarwal & Sulekh Chandra*

 

A PVC-based sensor for Nd3+ ions based on chelating inorganic ion-exchange resin [tetracycline-sorbed zirconium(IV) tungstophosphate (TC-ZWP)] as an electroactive material has been prepared. The sensor exhibits a Nernstian response for Nd3+ ions over a wide concentration range (1´10–1 - 5´10–5 M), when plotted on semi-log paper. The detection limit has been found to be 1´10-5 M. It has a response time of about 25 sec and can be used for at least 45 days without any divergence in its potential. The proposed membrane sensor reveals good selectivity for Nd3+ with regard to other trivalent lanthanide metal ions and could be used in the pH range 3-7, as well as in the partially non-aqueous media. Analytical applications of the electrode have been evaluated for the quantitative determination of Nd3+ in Sibaiya phosphate ore. The sensor has also been successfully used as an indicator electrode in the potentiometric titration of Nd3+ against EDTA.