Indian Journal of Chemistry

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

 

VOLUME 41A

NUMBER 4

APRIL 2002

CONTENTS

Papers

 

687

 

 

Determination of pair-interaction potential function for O2-O2 from viscosity data of gases

 

 

 

 

Behzad Haghighi* & Mohsen Najafi

 

 

 

A direct inversion procedure is used to obtain the effective isotropic part of the pair-interaction potential for O2-O2 from the corresponding states viscosity. This technique represents a distinct advance over the traditional methods for force fitting data to potential functions of primitive forms.

 

692

 

Effect of vanadia on physico-chemical and

catalytic characteristics of dysprosia

 

 

 

 

S Sugunan* & N K Renuka

 

 

 

Dy2O3/V2O5 systems have been prepared by wet impregnation method and characterized using different analytical techniques. Catalytic activity of the supported systems towards the vapour phase methylation of phenol are studied. Vanadia incorporation increases the selectivity of higher methylated phenols.

 

 

701

 

Structure and vanadium 3d1 polaron dynamics in the V2O5-P2O5-M2O (M=Li, Na, K) glasses

 

 

 

 

 

B B Das*, U Santhosh & S P Poongothai

 

 

 

Studies on the V2O5-P2O5-M2O (M=Li, Na, K) glasses show that the associated radii of vanadium 3d1 small polaron on a V4+ site are nearly the same but slightly less than the modifier free glass. The fairly lower values of k as compared with the modifier free glass of 0.74 indicates highly “squeezed” O-VO4…O unit in the glasses.

 

 

706

 

Excess molar volumes and viscosities of binary mixtures of diethylene glycol dibutyl ether with chloroalkanes at 298.15 K

 

 

 

 

 

Amalendu Pal* & Rakesh Kumar Bhardwaj

 

 

 

Excess molar volumes and dynamic viscosities for mixtures of diethylene glycol, dibutyl ether + dichloro-methane, + trichloromethane, and + tetrachloromethane have been determined as a function of composition at 298.15 K and atmospheric pressure. The results have been discussed in terms of dipole–dipole interactions between diethylene glycol, dibutyl ether and chloroalkanes.

712

 

Kinetics of substitution of aqua ligands from cis-diaqua(ethylenediamine)platinum(II) perchlorate by guanosine in aqueous medium

 

 

 

 

 

 

Partha S Sengupta, Ramanath Sinha,

Sujit K Bera & Gauri S De*

 

 

718

 

Studies on reactions of organic bases and nucleophiles with bis-(p-nitrophenyl) methyl-phosphonothionate

 

 

 

 

 

Shefali Saxena & Purnanand*

 

 

 

723

 

Reactivity ratio determination and complete spectral assignment of 4 -vinyl pyridine - ethyl acrylate copolymer by NMR spectroscopy

 

 

 

Sunita Hooda

 

 

 

4 - Vinyl pyridine - ethyl acrylate copolymers of different compositions have been prepared by free radical bulk polymerization. The complete spectral assignment of these copolymers have been done with the help of Distortionless enhancement by polarization transfer and two- dimensional heteronuclear single quantum coherence spectra.

 

730

 

Synthesis and characterization of mixed aromatic - aliphatic polyamides

 

 

 

 

 

 

 

Utkarsh Shukla, Ismail Mathakiya &

Animesh Kumar Rakshit*

 

 

737

 

Synthesis, characterization and crystal structure of dichlorobis(N6-furfuryladeninium) copper(II) chloride

 

 

 

 

 

 

 

 

 

 

B Umadevi,  N Stanley, P Thomas Muthiah* &

B Varghese

 

741

 

Synthesis and characterisation of ruthenium(III) complexes containing dibasic tetradentate Schiff bases

 

 

 

 

T Daniel Thangadurai & K Natarajan*

 

 

 

 

Notes

 

746

 

Conductance studies of alkali iodides in mixed organic solvents II: Conductance measurements in N, N-dimethylformamide-ethanol mixed solvents

 

 

Welford-Abbey Lolo Izonfuo*,

Charles Chuku Obunwo &

Gideon Obinuchi Chukunda

 

 

 

Limiting ionic conductivities for Na+, K+ and Cs+ ions have been obtained at 25ºC in mixtures of ethanol and N, N-dimethylformamide over the entire solvent composition range and in the pure solvents. The results suggest that ion-solvent interactions is the dominant factor which influences the conductance behaviour of Na+, K+ and Cs+ ions in N, N-dimethylformamide-ethanol mixed solvents.

 

751

 

Partial molal volume and partial molal compressibility of polyethylene glycol in water

 



 

A K Puri, N K Soni*, Amit Pandey &

Ashish K Sharma

 

 

 

Studies of partial molal volume and partial molal compressibility of polyethylene glycol in water show that values of apparent molal volume at infinite dilution are gradually decreasing with increase in concentration and molar refraction values increases with increase in the molecular weight of polyethylene glycol.

 

 

756

 


Macrocycles—Catalysts for autooxidation of thiols

 

 

 


Randhir Singh* & Pankaj Kumar

 

 

 

 

 

758

 

Kinetic solvent effects on reaction rates for the acidic hydrolysis of dihydroxamic acid

 

 

 

Kallol K Ghosh* & S K Patle

 

 

 

Kinetic solvent effects on reaction rates for the acidic hydrolysis of dihydroxamic acid reveal that the thermodynamic parameters are sensitive to the structural changes in the bulk solvent phase.

 

 

763

 

Bioinorganic studies on Co(II), Ni(II) and Cu(II) tellurite complexes with 2,2¢-bipyridyl ligand

 

 

 

 

 

 

Chitra Gupta & R K Goutam*

 

 

 

 

 

767

 

 

 

 

 

 

 

 

Synthesis and characterization of copper (II) and nickel(II) arylcarboxylates complexes with cyanopyridines

 

 

 

 

G D Bajju

 

 

 

 

 

771

 

Mixed-ligand complexes of cobalt(II) and nickel(II) with 2-sulphanylbenzothiazolate and (N,N) chelating ligands

 

 

 

 

 

Nanhai Singh* & Sushmita Gupta

 

 

 

A series of new, neutral [M(C7H4NS2)2(phen)] and salt-like [M(N-N)3](C7H4NS2)2, mixed-ligand complexes {M = Co(II) or Ni(II); C7H4NS2- = 2-sulphanylbenzothiazolate, N-N = 1, 10-phenanthroline or ethylenediamine have been synthesized and characterized. The temperature dependence (303-373 K) of the compressed pellet conductivity together with the band gaps in the 0.26-2.87 eV range show semiconducting behaviour of the compounds.

 

 

774

 

Synthesis, characterization and redox behaviour of camphorquinone monooximate complexes of osmium(II), -(III) and -(IV)

 

 

Doyel Bose, Hafijur Rahaman,

Pradyut Kumar Das, Chittaranjan Sinha &

Barindra Kumar Ghosh*

 

 

 

 

780

 

Synthesis and characterization of niobium(V) complexes with terdentate ONO donor hydrazones

 

 

 

 

 

 

 

 

 

 

 

 

V M Naik & N B Mallur*

 

 

 

785

 

Schiff base derivatives of tungsten carbonyl

 

 

 

 

 

 

 

 

Amar Srivastava* & A K Shrimal

 

 

 

 

Authors for correspondence are indicated by (*)


 

 

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 687-691

 

 

Determination of pair-interaction potential function for O2-O2
from viscosity data of gases

 

Behzad Haghighi*  & Mohsen Najafi

 

A direct inversion procedure is used to obtain the effective isotropic part of the pair-interaction potential for O2-O2 from the corresponding states viscosity over a range of reduced temperature extending from 1 to 100. We have used the experimentally reduced orientational average viscosity collision integrals obtained from the corresponding-states correlation and performed INVERT to determine the reduced potential energy curve corresponding to the collision integral. This directly determined potential is in excellent agreement with the ESMSV-type independently known potential of Brunetti et al. This accurate inverted potential can be used to obtain the orientation averaged viscosity collision integrals and the dimensionless ratios which are essential to calculate other transport properties. The advantages of the inversion method are that, the technique represents a distinct advance over the traditional methods for force fitting data to potential functions of primitive forms and lengthy multiparameter fitting procedure is largely removed.

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 692-700

 

 

 

Effect of vanadia on physico-chemical and catalytic characteristics of dysprosia

 

S Sugunan* & N K Renuka

 

Physico-chemical characterization of Dy2O3/V2O5 systems prepared through wet impregnation method has been carried out using various techniques like EDX, XRD, FTIR, thermal studies, BET surface area, pore volume and pore size distribution analysis. The amount of vanadia incorporated has been found to influence the surface properties of dysprosia. The spectroscopic results combining with X-ray analysis reveal that vanadia species exist predominantly as isolated amorphous vanadyl units along with crystalline dysprosium orthovanadate. Basicity studies have been conducted by adsorption of electron acceptors and acidity and acid strength distribution by temperature programmed desorption of ammonia. Cyclohexanol decomposition has been employed as a chemical probe reaction to examine the effect of vanadia on the acid base property of Dy2O3. Incorporation of vanadia titrates the Lewis acid and base sites of Dy2O3, while an enhancement of Bronsted acid sites has been noticed. Data have been correlated with the catalytic activity of these oxides towards the vapour phase methylation of phenol.

 

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 701-705

 

Structure and vanadium 3d1 polaron dynamics in the

V2O5-P2O5-M2O (M=Li, Na, K) glasses

 

B B Das*, U Santhosh & S P Poongothai

 

 

Studies on the V2O5-P2O5-M2O (M=Li, Na, K) glasses show that the associated radii of vanadium 3d1 small polaron on a V4+ site are nearly the same but slightly less than the modifier free glass. However, the average transition metal (TM)  ion separation in the glasses are nearly the same as in the network modifier free glass. The calculated values of the magnitude of exchange integral for the glasses in the range 0.021-0.023 eV as compared with that of 0.04 eV of the network modifier free 70V2O5-30P2O5 glass by approximating unit lattice vector, a, by polaron radius, rp appears plausible. The giso-values at 300 K and 77 K, Aiso-values at 77 K and peak-to-peak linewidth, DH, at 300 K are nearly same in the glasses. However, the giso=values are less than that of 1.963 of the modifier free glass at 300K. The values of Fermi contact term, k and b2* the coefficient of vanadium 3dxy orbital are also similar in the glasses. However, the fairly lower values of k as compared with the modifier free glass of 0.74 indicates highly “squeezed’ O-VO4…O unit in the glasses.

 

 

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 706-711

 

 

 

Excess molar volumes and viscosities of binary mixtures of diethylene glycol
dibutyl ether with chloroalkanes at 298.15 K

Amalendu Pal*  & Rakesh Kumar Bhardwaj

 

Excess molar volumes (VmE) and dynamic viscosities (h) for mixtures of diethylene glycol dibutyl ether + dichloromethane, + trichloromethane, and + tetrachloromethane have been determined as a function of composition at 298.15 K and atmospheric pressure. The excess molar volumes VmE are all negative over the whole composition range. The viscosity data have been correlated by the methods of Kendall and Monroe, Grunberg and Nissan, Tamura and Kurata, Hind, Katti and Chaudhary, and of McAllister. The deviations in viscosities (Dlnh) and excess energies of activation (DG*E) for viscous flow have been calculated from the experimental results. These results have been discussed in terms of dipole–dipole interactions between diethylene glycol dibutyl ether and chloroalkanes and magnitudes of interactions decreasing with the dipole character of the molecule. A short comparative study with results for mixtures with polyethers or alkoxyethanols and chloroalkanes is also presented.

 

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 712-717

 

 

 

Kinetics of substitution of aqua ligands from

cis-diaqua(ethylenediamine)platinum(II) perchlorate by

guanosine in aqueous medium

 

Partha S Sengupta, Ramanath Sinha, Sujit K Bera & Gauri S De*

 

 

The kinetics of the interaction of guanosine with cis-[Pt(en)(H2O)2]2+ have been studied spectrophotometrically as a function of [Pt(en)(H2O)22+], [guanosine] and temperature at pH 4.0 where the substrate complex exists predominantly as the diaqua species. Base stacking and metal induced macrochelate formation of guanosine plays a vital role in determining the concentration limit of guanosine during kinetics. Substitution occurs in two consecutive steps; both dependent on the guanosine concentration. Activation parameters for both steps have been calculated. The low DH1# (36.28 ± 0.5 kJ mol-1) and large negative values of DS1# (-125.3 ± 1.5 J K-1mol-1) as well as DH2# (36.03 ± 0.6 kJ mol-1) and DS2# (-149.2 ± 1.9 J K-1 mol-1) indicate associative modes of activation for both the ligand substitution processes in the two consecutive steps.

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 718-722

 

 

 

Studies on reactions of organic bases and nucleophiles with bis-(p-nitrophenyl) methylphosphonothionate

 

Shefali Saxena & Purnanand*

 

Bis-(p-nitrophenyl) methylphosphonothionate (b-p-NPMPT) (I) reacts with amines in aqueous medium via general base catalysis of water attack . The rate is first order each in [substrate] and [amine]. Solvent deuterium isotope effect, k2(H2O) / k2(D2O), is greater than 2 for amine reactions. Different classes of amines follow Brönsted relation with a slope of 0.40. Fluoride and phosphate ions react with (I) by nucleophilic mechanism. At higher fluoride ion concentration, 2 mol of p-nitrophenol (p-NP) is released by a first order process. At lower fluoride ion concentration less than 2 mol of p-NP is produced. k2(H2O)/k2(D2O) for the reaction of fluoride and phosphate ions with b-p-NPMPT@ 1. It is believed that steric crowding in the transition state causes reaction of (I) with amine to proceed via general base mechanism and that of fluoride ion, oxyanions and phosphate anions through a nucleophilic mechanism.

 

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 723-729

 

 

Reactivity ratio determination and complete spectral assignment of 4-vinyl pyridine-ethyl acrylate
copolymer by NMR spectroscopy

 

Sunita Hooda

 

4-Vinylpyridine-ethyl acrylate (V/E) copolymers of different compositions have been prepared by free radical bulk polymerization. The copolymer composition has been calculated from 1H-NMR spectra. The comonomer reactivity ratios of V/E copolymer have been calculated from linear Kelen-Tudos (KT) and non-linear error-in -variables method (EVM). The reactivity ratios obtained from KT and EVM are rV = 0.34 ± 0.07, rE = 0.23 ± 0.07 and rV =0.36 ± 0.08, rE = 0.25 ± 0.04 respectively. The theoretical triads concentration has been determined from statistical model using terminal model reactivity ratios. The complete spectral assignment of these copolymers has been done with the help of distortionless enhancement by polarization transfer (DEPT) and two dimensional heteronuclear single quantum coherence (HSQC) spectra. The various type of 1H-1H couplings in copolymer have been assigned with the help of 2D-total correlated spectroscopy (TOCSY).

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 730-736

 

 

Synthesis and characterization of mixed aromatic-aliphatic polyamides

 

Utkarsh Shukla, Ismail Mathakiya & Animesh Kumar Rakshit*

 

Polyamide of benzidine/adipic acid (PA-1) and that of terephthalic acid/hexamethylene diamine (HMDA) (PA-2) have been synthesised by polycondensation method via acid chloride route. The polymers have been characterised by elemental analysis, FTIR, solid state NMR, TGA, DSC, WAXD, viscosity studies and optical polarized microscopy. The activation energy associated with the decomposition has been determined using Broido’s method. Melting point and enthalpy change (DH) were evaluated by DSC analysis whereas crystallinity of polymer samples are determined by WAXD. The viscosity behaviour of PA-1 in DMAC + 5% LiCl and PA-2 in m-cresol and also in methanol/m-cresol mixed solvents of various ratios at different temperatures have been studied. The intrinsic viscosity [h] shows significant effect with respect to both temperature and mixed solvents. The voluminosity (VE) and shape factor (n) have also been computed from the viscosity data.

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 737-740

 

 

 

 

Synthesis, characterization and crystal structure of

dichlorobis(N6-furfuryladeninium) copper(II) chloride

 

B Umadevi, N Stanley, P Thomas Muthiah* & B Varghese

 

A copper complex of kinetin(N6-furfuryladenine), a plant growth regulator, has been synthesized. Crystal Data: Monoclinic space group C2/c with cell dimensions a=11.711(2)Å, b=7.930(2)Å, c=28.672(6)Å, b=101.64(2)°, Z=8 and R=0.0806. Cu2+ exhibits a distorted octahedral geometry - four chlorides and two N9 atoms of the adenine moiety achieving the octahedral environment around copper. The adenine moiety exists as the N3 protonated N7-H tautomer. Protonation has enhanced the internal angles at the site of protonation. Based on charge neutrality, N1 is also assigned a proton with 0.5 occupancy. There is a paucity of data on molecular dimensions of adenine moiety with this type of simultaneous N3, N7 protonation and N9 coordination. The N6 substituent is distal to N7. The dihedral angle between the adenine moiety and the furfuryl ring is 63.2(3)º. The coordination has not significantly affected the inherent conformation of the kinetin moiety even under acidic conditions.

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 741-745

 

 

Synthesis and characterisation of ruthenium(III) complexes
containing dibasic tetradentate Schiff bases

T Daniel Thangadurai & K Natarajan*

 

 

Several hexacoordinated ruthenium (III) complexes of the type [RuX(LL')(EPh3)] (where, X=Cl or Br; LL'=tetradentate Schiff bases; E=P or As) have been synthesised by the reactions of [RuX3(EPh3)3] or [RuBr3(PPh3)2(MeOH)] with appropriate Schiff bases having the donor groups (O,N) viz., o-hydroxy acetophenone ethylenediimine(o-hyacen), o-hydroxy acetophenone propylenediimine (o-hyacpn), o-hydroxy acetophenone tetramethylenediimine (o-hyactn) and o-hydroxy acetophenone orthophenylenediimine (o-hyacopn) in 1:1 molar ratio. All the complexes have been characterised on the basis of elemental analyses and spectral (IR, electronic and EPR), electrochemical and magnetic moment data. The antibacterial activities have also been tested for these complexes.

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 746-750

 

 

Conductance studies of alkali iodides in mixed organic solvents II: Conductance measurements in
N, N-dimethylformamide-ethanol mixed solvents

 

Welford-Abbey Lolo Izonfuo*, Charles Chuku Obunwo &

Gideon Obinuchi Chukunda

 

Limiting ionic conductivities for Na+, K+ and Cs+ ions have been obtained at 25ºC in mixtures of ethanol and N, N-dimethylformamide over the entire solvent composition range and in the pure solvents. Variations in limiting ionic conductivities for the ions have been observed as the mole fraction of ethanol in the mixed solvents varied. These variations show a maximum at the solvent composition of near 0.8 mole fraction of ethanol in the mixed solvents for the three ions. Using Nightingale's modification of the Robinson-Stokes treatment, the radii of the solvated ions in the various solvent systems have been calculated and the solvation numbers of Na+, K+ and Cs+ in the various solvents calculated therefrom. The solvation numbers of Na+, K+ and Cs+ range between 2.37-3.28, 2.23-2.73 and 1.89-2.43 respectively in the various solvent mixtures. Plots of the solvation numbers as a function of solvent composition show a minimum at about 0.80 ethanol mole fraction which coincides with the maximum in the limiting ionic conductivities. The results of the study suggest that ion-solvent interactions which account for the extent of solvation of the ions is the dominant factor which influences the conductance behaviour of Na+, K+ and Cs+ ions in N,N-dimethyl­formamide-ethanol mixed solvents. Factors such as solvent viscosities and densities appear to play less dominant roles.

 

 

 

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 751-755

 

Partial molal volume and partial molal
compressibility of polyethylene glycol in water

A K Puri, N K Soni*, Amit Pandey & Ashish K Sharma

 

Using the experimental data of Gerecze [Acustica, 38 (1977) 51] on ultrasonic velocity, density and refractive index of aqueous polyethylene glycol, the values of partial molal volume (fV0), experimental slope (SV) and partial molal compressibility (fK0) at different temperatures, interaction coefficient (Q), molal volume of Vand's equation at 20°C (V) and molar refraction (Rm) have been calculated. Validity of Vand's equation and molar refraction equation for polyethylene glycol is displayed. Temperature dependence hydration nature of polyethylene glycol has also been discussed.

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 756-757

 


Macrocycles—Catalysts for autooxidation of thiols

 


Randhir Singh* & Pankaj Kumar

 

Me4dibenzo (b, i) 1,4,8,11-tetraaza cyclotetradecatetraene cobalt(II) macrocyclic complex has been used as catalyst for the oxidation of substituted thiophenols viz. 4-methyl, 4-methoxy, 3-amino etc. The catalyst seems to be as effective as its unsubstituted macrocycle. The yield of diphenyldisulphide is 70%. The rate of oxidation of thiols is affected by methyl groups on the macrocyclic ring and it may be due to electronic or steric effect.

 

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 758-762

 

Kinetic solvent effects on reaction rates for the acidic hydrolysis of dihydroxamic acid

 

Kallol K Ghosh* & S K Patle

 

Kinetic solvent effects on a key A-Ac-2 type reaction, i.e., acidic hydrolysis of succinodihydroxamic acid in aqueous mixtures (10-80% v/v) of some protic cosolvents viz methanol, ethanol, propan-2-ol and aprotic cosolvents viz 1,4-dioxane, acetonitrile, dimethyl sulphoxide, acetone, dimethylformamide have been analysed in the light of solvation energetics of the initial state and transition state. The observed log ky - solvent composition profiles reveal that the rate increases with increasing percentage of solvents. Linear solvation energy relationships and solvatochromic parameters (a, b, p*), effects of dielectric constant and ET have been applied to quantity solvent effects on reaction rates. The thermodynamic parameters (DH¹ and DS¹) are sensitive to the structural changes in the bulk solvent phase.

 

 

 

 

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 763-766

 

 

Bioinorganic studies on Co(II), Ni(II) and Cu(II) tellurite complexes with 2,2’- bipyridyl ligand

 

Chitra Gupta & R K Goutam*

 

Cubic Co(II) and orthorhombic Ni(II) and Cu(II) tellurite complexes of 2,2’- bipyridyl ligand have been synthesised, characterised and screened for their antimicrobial and pharmacological activity against a number of micro-organisms. On the basis of elemental analysis and molar conductance, a general formula [M (bipy)n (H2O)x] TeO3 YH2O (where M(II)=Co (II), Ni(II) and Cu(II) ; n=2 for Co(II) & Cu(II) complexes and 3 for Ni(II) complexes ; X=zero for Ni(II) & Cu (II) and 2 for Co(II) complex ; Y=1,6 or 3 for Co(II), Ni(II) and Cu(II) complexes respectively) has been suggested for the complexes under study. The geometries of the complexes have been proposed on the basis of magnetic moment, electronic and infrared spectral data. The TGA studies have also been carried out to know the pattern of their decomposition. The crystal system, lattice parameters, unit cell volume and number of molecules in it have been determined by X-ray differaction data.

 

 

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 767-770

 

Synthesis and characterization of copper (II) and nickel(II) arylcarboxylate complexes with cyanopyridines

G D Bajju

 

 

The coper(II) and nickel(II) arylcarboxylates react with 2-, 3- and 4-cyanopyridines (CNPy) in an organic medium to give solid complexes having general formula [M(O2CR)2L] and [M(O2CR)2L2], R=o-ClC6H4-, o-OCH3 C6H4- and m-OCH3C6H4-; L=2-, 3- and 4-CNPy). All the complexes with Cu(II) arylcarboxylates are of 1:1 stoichiometry irrespective of the amount of ligand added and have been shown by physico-chemical methods to be binuclear, containing bidentate bridging carboxylate group. Ni(II) arylcarboxylate complexes are mononuclear having bidentate chelating carboxylate group. Cyanopyridine moiety functions as a monodentate ligand coordinating through pyridine nitrogen atom.

 

 

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 771-773

 

Mixed-ligand complexes of cobalt(II) and nickel(II) with 2-sulphanylbenzothiazolate and (N,N) chelating ligands

Nanhai Singh* & Sushmita Gupta

 

A series of new, neutral [M(C7H4NS2)2(phen)] and salt-like [M(N-N)3](C7H4NS2)2, mixed-ligand complexes {M=Co(II) or Ni(II); C7H4NS2-=2-sulphanylbenzothiazolate, N-N=1,10-phe­nan­throline (phen) or ethylenediamine (en)} have been prepared and characterized by elemental analysis, IR, UV-visible and conductivity techniques. All the compounds exhibit srt in the
10-13–10-6 S cm-1 range. Temperature dependence (303-373 K) of the compressed pellet conductivity together with the band gaps in the 0.26-2.87 eV range show semiconducting behaviour of the compounds.

 

 

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 774-779

 

Synthesis, characterization and redox behaviour of camphorquinone monooximate complexes of osmium(II), -(III) and -(IV)

 

Doyel Bose, Hafijur Rahaman, Pradyut Kumar Das, Chittaranjan Sinha & Barindra Kumar Ghosh*

 

A group of dihalogenobis complexes of the type [OsX2(HA)(A)] (1) and mixed-tris chelates of types [Os(A)(L)2]-ClO4.H2O (2), [Os(A)(Q)2] (3) and [Os(A)(Q)2]ClO4.H2O (4) [where X=Cl or Br; HA=camphor-quinone monooxime; L = 2-(arylazo)pyridines and HQ=quinolin-8-ol and its derivative] have been prepared by distinctly different synthetic routes and characterized by microanalytical, IR, EPR, UV-Vis and electro-chemical results. Reversible/nearly-reversible osmium(III)-osmium(II) and osmium(IV)-osmium(III) couples are invariably seen in all the complexes.

 

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 780-784

 

 

Synthesis and characterization of
niobium(V) complexes with terdentate ONO donor hydrazones

V M Naik & N B Mallur*

 

The metal complexes of niobium(V) with 2-benzimidazolyl mercaptoaceto hydrazones have been synthesized in dry alcohol under nitrogen atmosphere and characterized by elemental analyses, molar conductance measurements, infrared, electronic and 1H NMR spectral studies. The spectral studies show that the hydrazones reacts in enol form and act as dibasic terdentate ONO donor nature. The thermal stabilities have been studied and the kinetics of these complexes are calculated using Coats–Redfern and MKN methods. From the results, a coordination number seven for niobium ion in the complexes of the type Nb(L)2Cl is proposed. All the ligands and their niobium(V) complexes

 

 

 

Indian Journal of Chemistry

Vol. 41A, April 2002, pp. 785-790

 

 

Schiff base derivatives of tungsten carbonyl

 

Amar Srivastava* & A K Shrimal

 

The Schiff bases (SB) viz., 1,2-bis(4-methylbenzylidene­imine)propane (SB1), 1,2-bis(4-methoxybenzylideneimine)pro-pane (SB2), 1,2-bis(4-N,N-dimethylaminobenzylideneimine) propane (SB3), 1,2-bis(4-methylacetophenoneimine)propane (SB4) and 1,2-bis(4-methoxyacetophenoneimine)propane (SB5) react with tungsten hexacarbonyl in xylene to give cis-disubstituted derivatives, cis-[(SB)W(CO)4]. Schiff base bridged dinuclear [(Ph3E)(CO)4W(m-SB)W(CO)4(Ph3E)] derivatives have been synthesized with [(Ph3E)W(CO)5] (E = P or As). Cis-[(SB)W(CO)4] yielded [(SB)W(CO)3X2] when reacted with X2 (X = Br or I) but produced CO free product [(SB)WCl4] after reaction with chlorine. The complexes have been characterized by elemental analysis, infrared and magnetic moment studies.