Indian Journal of Chemistry
Sect. A: Inorganic, Bio-inorganic, Physical, Theoretical & Analytical

 

VOLUME 41A

NUMBER 2

FEBRUARY 2002

 

CONTENTS

 

Advances in Contemporary Research

 

 

245

 

Developments of water electrolysis technology by solid polymer electrolyte

 

 

 

 

 

Sang-Do Han, Kee-Bae Park, Ravi Rana &

K C Singh*

 

 

Water electrolysis by solid polymer electrolyte is the most promising technology for large-scale hydrogen production for future. In this review, the selection of high activity electrocatalysts, methods to prepare SPE electrocatalyst composites, their stability, the pretreatment of solid polymer electrolyte membrane for the deposition of electrocatalysts, the fabrication of current collectors, the scale up of water electrolyzers and recent advances has been discussed.

 

Papers

 

 

254

 

 

Direct determination of the HeKr interaction potential from the extended
principle of corresponding states

 

 

Elaheh K Goharshadi* & Majid Moinossadati

 

 

 

The pair potential energy function of HeKr determined using a direct inversion of the experimentally reduced viscosity collision integrals is in good agreement with the previously determined potential. It has been used to predict the viscosity and diffusion coefficients of He-Kr binary mixtures.

 

 

259

 

Para-selective ethylation of t-butylbenzene with diethyl carbonate over mesoporous molecular sieves

 

V Umamaheswari, M Palanichamy, Banumathi Arabindoo & V Murugesan*

 

 

 

The vapour phase ethylation of t-butylbenzene (t-BB) with diethyl carbonate has been studied over mesoporous molecular sieves. The selectivity of para-t-butylated products is favoured at lower temperature while higher temperature favoures ethylbenzene.

 

 

266

 

Refractive indices of binary liquid mixtures of (decane + benzene) and (hexadecane + benzene, or + hexane) at 303.15, 308.15 and 313.15 K

 

 

S C Bhatia*, Neelima Tripathi & G P Dubey

 

 

 

Refractive indices of the binary liquid mixtures of (decane + benzene), and (hexadecane + benzene, or + hexane) have been determined over the entire composition range. Deviations at different temperatures have been computed and fitted to the Redlich-Kister polynomial equation to derive the binary coefficients.

 

 

270

 

Kinetics and mechanism of permanganate oxidation of phenylphosphinic acid
in acid perchlorate solution

 

 

 

 

 

Kamla Sharma & Raj Narain Mehrotra*

 

 

 

Kinetics and mechanism of permanganate oxidation of phenylphosphinic acid has been determined in acid perchlorate solution The stoichiometry of the title reaction is expressed by the equation, MnO4- + 2C6H5HP(O)OH + 4H+ Mn(III) + 2C6H5PO(OH)2 + 2H2O. The kinetics and the rapid scan of the reaction mixture suggest the formation of the complexes by C6H5HP(O)OH(C1, K1) and C6H5HP(O)O- (C2, K2) with MnO4- ion.

 

 

 

279

 

Synthesis, structure, spectroscopy and antitumor activity of hydroxy naphthoquinone thiosemicarbazone and its metal complexes

against MCF-7 human breast cancer cell line

 

 

 

 

 

 

 

Dilip Kumar Saha, Subhash Padhye*, Ekkehard Sinn & Chris Newton

 

 

 

 

284

 

Synthesis, characterization and structure of Ti(IV) complexes of
hydroxy-rich ligands

 

 

 

 

 

 

 

 

P Venkateshwara Rao, Erkki Kolehmainen & Chebrolu P Rao*

 

 

 

 

 

290

 

Synthesis, characterization and thermal studies of magnesium (II) complexes of ortho and para-aminobenzoic acids

 

 

B R Srinivasan*, Sarvesh C Sawant &

Sunder N Dhuri

 

 

 

The synthesis and spectroscopic characterization of ortho or para-aminobenzoate complexes of Mg(II) namely [Mg(H2O)6](X)2.2H2O (X=2-aminobenzoate (2-aba) 1 and X=4-aminobenzoate (4-aba) 2). Compound 2 can be reversibly dehydrated unlike 1

 

 

297

 

Structural chemistry and thermal properties of some pyrimidine complexes

 

 

 

Mamdouh S Masoud* Saeda A Abou El Enein & Hesham M Kamel

 

 

 

A few complexes of Fe(III), Co(II), Ni(II) and Cu(II) with uracil, 6-amino uracil, and those with substituted phenyl azo-6-amino uracils containing o-methyl, p-carboxy and o-carboxy substituents and 5,5-diethyl barbituric acid sodium salt have been synthesized and characterized.

 

 

Notes

 

 

304

 

Surface properties and catalytic activity of vanadia supported on samaria

 

 

 

S Sugunan* & N K Renuka

 

 

 

 

Sm2O3 - vanadia catalysts have been prepared by wet impregnation method using NH4VO3 solution and the surface properties of the prepared catalysts have been studied. It has been observed that the selectivity of the products depends upon the composition of the supported system.

 

 

 

 

308

 

Photoelectrochemical studies on thermally treated (ZnCd) Se films

 

 

 

 

 

 

A K Shukla & Kaman Singh*

 

 

 

Photoresponsive mixed metal chalcogenide films of (ZnCd) Se of desired composition have been prepared by electrochemical codeposition and subjected to thermal treatment. The thermally treated preparations have been endowed with increased stability and somewhat improved photoresponsiveness and they exhibit increased resistance towards impairment due to electrochemical corrosion.

 

 

312

 

Apparent molar volume and apparent molar

compressibility of glycine in aqueous vanadyl sulphate solutions at 298.15, 303.15 and 308.15 K

 

 

 

P G Rohankar & A S Aswar*

 

 

 

Apparent molar volume and apparent molar compressibility of glycine in aqueous vanadyl sulphate solutions have been determined. The negative transfer of volume has been observed for 0.1 M and 0.05 M vanadyl sulphate solutions.

 

 

316

 

Kinetics of palladium(II) catalysed oxidation of mercury(I) by iron(III)-2,2-bipyridyl complex

 

S A Chimatadar, S B Koujalagi & S T Nandibewoor*

 

 

 

Fe(III)aq + 2(BipyH+) [Fe(Bipy)2]3+ + 2H+

(complex)    (2)

Complex + Pd (II) Pd(III) + FeII (bipy)3 (3)

slow

 

Pd(III) + Hg (I) Hg (II) + Pd (II)

 (4)

 

 

 

321

 

Kinetics and mechanism of the oxidation of formic and oxalic acids by tetrabutylammonium tribromide

 

 

 

 

 

 

 

 

 

 

Jaya Gosain & Pradeep K Sharma*

 

 

 

 

325

 

Kinetics and mechanism of dissolution

and transformation of chloropinnoite in

water at 293-313K

 

 

 

 

Zhihong Liu*, Mancheng Hu, Shiyang Gao & Shuping Xia

 

 

The influence of temperature (293-313K) and stirring rate on the kinetics of dissolution and transformation of chloropinnoite (2MgO2B2O3MgCl214H2O) in water have been studied. The experimental results show that chloropinnoite dissolves incongruently in water.

 

 

330

 

Study on the supramolecular inclusion complex of b-cyclodextrin with retinoic acid

 

 

Yanling Zhang, Kaijun Liao, Weisheng Liu & Xueyi Ma*

 

 

 

Inclusion compound of retinoic acid with b-cyclodextrin has been prepared by coprecipitating method and the structure of resulting product has been characterized. The results indicate that the formed supramolecule self-assembles in aqueous solution in the molar ratio 2:1 (host: guest)

 

 

333

 

 

Synthesis and characterization of epoxy resin in the presence of p-acetylbenylidene triphenylarsoniumylide-mercuric chloride complex

 

 

Saurabh Pandey & A K Srivastava*

 

 

 

 

 

 

 

339

Synthesis, magnetic and spectral studies of some new mixed-ligand nitrosyl complexes of chromium(I)

 

 

 

R C Maurya*, A Pandey & R Verma

 

 

 

 

342

 

Synthesis and characterization of chlorodibenzyltin(IV) complexes with N,N-dialkyl dithiocarbamate ligands and crystal structure of (PhCH2)2SnCl(S2CNMe2)

 

 

 

 

Handong Yin*, Chunlin Ma & Yong Wang

 

 

 

 

 

346

 

A new single pulse method for the measurements of photosensitized singlet oxygen quantum yield

 

 

 

R Venkatesan*, S Tamijselvy, N Periasamy,

T M Rajendiran, P S Rao & T S Srivastava

 

 

 

A new simpler relative method for estimating photosensitized singlet oxygen quantum yield has been developed. In this method a strong depletion signal is observed when porphyrin (2 mM) and 1,3-diphenylisobenzofuran (DPBF, 500 mM) are irradiated using second harmonic 532 nm Nd-YAG laser pulse and monitored at 410 or 415 nm by a ultraviolet filtered white light.

 

 

 

350

 

 

Announcements

 

 

Authors for correspondence are indicated by (*)


 

 

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 245-253

 

 

Developments of water electrolysis technology by solid polymer electrolyte

Sang-Do Han, Kee-Bae Park, Ravi Rana & K C Singh

 

Water electrolysis by solid polymer electrolyte is the most promising technology for large-scale hydrogen production for future. The concept introduced by General Electric Co. (U.S.A) in late sixties has been adopted by Brown Boveri Research Center, Baden, Switzerland and more recently by Japan under WE-NET Japanese Hydrogen Programme Project. For the last 25 years, this field has witnessed a lot of activity, in research and development of energy efficient water electrolyzers. In this review, the selection of high activity electrocatalysts, methods to prepare SPE electrocatalyst composites, their stability, the pretreatment of solid polymer electrolyte membrane for the deposition of electrocatalysts, the fabrication of current collectors, the scale up of water electrolyzers and recent advances has been discussed.

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 254 -258

 

Direct determination of the HeKr interaction potential from the extended
principle of corresponding states

Elaheh K Goharshadi & Majid Moinossadati

 

The pair potential energy function of HeKr has been determined using a direct inversion of the experimentally reduced viscosity collision integrals obtained from the corresponding-states correlation. The potential is in good agreement with the previously determined potential. The resulting potential has been used to predict the viscosity and diffusion coefficients of He-Kr binary mixtures and they are found to be in good agreement with the experiment.

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 259 -265

 

 

Para-selective ethylation of t-butylbenzene with diethyl carbonate over mesoporous molecular sieves

V Umamaheswari, M Palanichamy, Banumathi Arabindoo & V Murugesan

 

The vapour phase ethylation of t-butylbenzene (t-BB) with diethyl carbonate has been studied over mesoporous Al-MCM-41 (Si/Al = 50 and 90) and Al, Mg-MCM-41 [Si/(Al+Mg) = 50] from 200 to 400C. The products are benzene, ethylbenzene (EB), p-diethylbenzene (p-DEB), p-t-butylethylbenzene (p-tBEB) and p-t-butylvinylbenzene (p-tBVB) . t-Butylbenzene conversion increases with increase in temperature up to 300C, but above this temperature it decreases. Ortho and meta-products are completely absent. Ethylbenzene is the product of ethylation of benzene and cracking of p-tBEB.The selectivity of para-t-butylated products is favoured at lower temperature while higher temperature favoures ethylbenzene selectivity. The influence of time on stream is examined over Al-MCM-41 (50) and the results are discussed in this paper.

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 266 -269

 

 

Refractive indices of binary liquid mixtures of (decane + benzene) and (hexadecane + benzene, or + hexane) at 303.15, 308.15 and 313.15 K

 

S C Bhatia, Neelima Tripathi & G P Dubey

 

Refractive indices at 303.15, 308.15 and 313.15K have been measured for the binary liquid mixtures of (decane + benzene), and (hexadecane + benzene, or + hexane) over the entire composition range. From the experimentally measured values, refractive index deviations at different temperatures have been computed and fitted to the Redlich-Kister polynomial equation to derive the binary coefficients and standard errors. Using various mixing rules, refractive indices of the binary liquid mixtures at 298.15K have been calculated theoretically and the results discussed in terms of average percentage deviations.

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 270 -278

 

Kinetics and mechanism of permanganate oxidation of phenylphosphinic acid
in acid perchlorate solution

Kamla Sharma & Raj Narain Mehrotra

 

The stoichiometry of the title reaction is expressed by the Equation, MnO4- + 2C6H5HP(O)OH + 4H+ Mn(III) + 2C6H5PO(OH)2 + 2H2O. The kinetics and the rapid scan of the reaction mixture suggest the formation of the complexes by C6H5HP(O)OH(C1, K1) and C6H5HP(O)O- (C2, K2) with MnO4- ion. The equilibrium constants of the complexes are H+ dependent. It is suggested that the complexes are formed by hydrogen bonds, P-H . O-Mn, and the redox involve the dissociation of H- from the P-H bond causing transfer of two electrons from substrate to MnO4- through -O- bridge. The relative stability of the complex C2 > C1 because K1 < K2 and, k1 > k2 where k1 and k2 are the rate constants for the decomposition of the complexes C1 and C2. The kinetics in perchlorate solution (m = 1 mol dm-3, LiClO4) under pseudo-first order conditions ([PPA] >> [MnO4-]) indicated that the H+ catalysed rate correlates with the expression kobs(Ka + [H+]) = a + b[H+] + c[H+]2 where kobs is the pseudo-first order rate constant and Ka is the dissociation constant of C6H5HP(O)OH. The [H+]2 term is likely due to the acid catalysis of C1. The activation parameters corresponding to k1 and k2 are reported.

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 279 -283

 

 

Synthesis, structure, spectroscopy and antitumor activity of hydroxy naphthoquinone thiosemicarbazone and its metal complexes

against MCF-7 human breast cancer cell line

 

Dilip Kumar Saha, Subhash Padhye, Ekkehard Sinn & Chris Newton

 

Coordinately unsaturated metal complexes of the stoichiometry [M(HL)Cl] and [Fe(HL)Cl2].2H2O have been isolated (where M=Cu(II), Ni(II), Pd(II) and Pt(II); HL=tridentate anion of H2L 3). The X-ray crystal structure for 4-hydroxy-3-methyl-1,2-naphthoquinone-1-thiosemicarbazone, 3 has been determined which crystallizes in space group P21/c, a = 7.430(3), b = 10.794(3), c = 17.216(5) , b =92.91(3)o, Z = 4, and have E configuration. The Cu(II) 3a, Ni(II) 3c, Pd(II) 3d and Pt(II) 3e complexes are found to possess square planar geometries, whereas Fe(III) complex 3b possesses a square pyramidal configuration. The in vitro activity of the synthesized compounds examined against human breast cancer cell line MCF-7 clearly indicates that metal complexation enhances antitumor activity, the highest being for the copper complex 3a.

 

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 284 -289

 

Synthesis, characterization and structure of Ti(IV) complexes of
hydroxy-rich ligands

P Venkateshwara Rao, Erkki Kolehmainen & Chebrolu P Rao

 

Coordination chemistry of two multi-hydroxy rich ligands has been explored with Ti(IV) by isolating the resultant products followed by their characterization. One of the products is also structurally characterized by single crystal XRD.

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 290 296

 

 

Synthesis, characterization and thermal studies of magnesium (II) complexes of ortho and para-aminobenzoic acids

B R Srinivasan, Sarvesh C Sawant & Sunder N Dhuri

 

The reaction of magnesium carbonate with ortho or para-aminobenzoic acid results in the formation of the complexes [Mg(H2O)6](X)2.2H2O (X=2-aminobenzoate (2-aba) 1 and X=4-aminobenzoate (4-aba) 2). The 2-aminobenzoate complex 1 has been characterised by metal analysis, isothermal weight loss studies, infrared, UV-Vis, 1H and 13C NMR spectra and X-ray powder diffraction. The 2-aba complex is relatively unstable as compared to the corresponding 4-aba analogue and slowly decomposes to [Mg(2-aba)2] with the loss of water molecules. This irreversible change is attributed to the disposition of the NH2 group with respect to the carboxylate group in the six-membered ring.

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 297 303

 

Structural chemistry and thermal properties of some pyrimidine complexes

 

Mamdouh S Masoud, Saeda A Abou El Enein & Hesham M Kamel

A few complexes of Fe(III), Co(II), Ni(II) and Cu(II) with uracil, 6-amino uracil, and those with substituted phenyl azo-6-amino uracils containing o-methyl, p-carboxy and o-carboxy substituents and 5,5-diethyl barbituric acid sodium salt have been synthesized and characterized by elemental analysis, magnetic moment and spectral measurements (IR, UV-vis, ESR). The IR spectra show that uracil exists in keto- enol tautomerism but 6-amino uracil possesses the keto amino-imine structure with some enol form. The iron complexes are with Oh geometry, while the cobalt complexes are with different geometries (square planar and Oh). The square planar copper complexes exist in ligand bridged structures. The nickel complexes are of tetrahedral configuration. In general, the azo group is involved in the structural chemistry of the azo complexes. The coordination bond length has been calculated. The thermal properties (TG and DTA) of the compounds and their complexes are measured and discussed and also the thermodynamic parameters are evaluated.

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 304-307

 

 

Surface properties and catalytic activity of vanadia supported on samaria

 

S Sugunan & N K Renuka

 

Sm2O3 - vanadia catalysts have been prepared by wet impregnation method using NH4VO3 solution. The surface properties of the prepared catalysts have been studied using FTIR, XRD, surface area and pore volume data. The acid-base properties of the system have been investigated by titrimetric method using Hammett indicators, adsorption of electron acceptors as well as decomposition of cyclohexanol. Phenol alkylation reaction by methanol has been carried out to investigate the catalytic activity. It has been observed that the selectivity of the products depends upon the composition of the supported system.

 

 

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 308-311

 

 

Photoelectrochemical studies on thermally treated (ZnCd) Se films

 

A K Shukla & Kaman Singh

Photoresponsive mixed metal chalcogenide films of (ZnCd) Se of desired composition have been prepared by electrochemical codeposition and subjected to thermal treatment at 400C in argon atmosphere under controlled conditions. Photoresponsiveness of thermally treated electrodes has been examined employing I-3 / I2 redox system and characterised by photoaction spectral (PAS) studies and impedance measurements. Thermal treatment of the electrodeposits is accompanied by inversion from p-to n-type semiconductivity and they exhibit somewhat lowered band gap perhaps due to recrystallisation. The thermally treated preparations have been endowed with increased stability and somewhat improved photoresponsiveness and they exhibit increased resistance towards impairment due to electrochemical corrosion.

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 312-315

 

 

Apparent molar volume and apparent molar compressibility of glycine in aqueous

vanadyl sulphate solutions at 298.15, 303.15 and 308.15 K

 

P G Rohankar & A S Aswar

Apparent molar volume and apparent molar compressibility of glycine in aqueous vanadyl sulphate solutions (0.10, 0.05 and 0.01 M) have been determined from 298.15 K to 308.15 K. The transfer of volumes for the transfer of glycine from water to aqueous vanadyl sulphate have been evaluated. Negative transfer of volume has been observed for 0.1 M and 0.05 M vanadyl sulphate solutions. The results are explained on the basis of electrostriction.

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 316-320

 

Kinetics of palladium(II) catalysed oxidation of mercury(I) by iron(III)-2,2-bipyridyl complex

 

S A Chimatadar, S B Koujalagi & S T Nandibewoor

Kinetics of oxidation of mercury(I) by iron(III)-2,2-bipyridyl in the presence of microamounts of palladium(II) has been studied spectrophotometrically in aqueous nitric acid and methanol media. The reaction exhibits first order each in [iron(III)-2,2-bipyridyl] and [palladium(II)] and zero order in [mercury(I)]. Increase in [HNO3] decreases the reaction rate. Added products do not have any significant effect on the reaction rate. A suitable reaction mechanism is proposed and the reaction constants of the different steps involved have been evaluated.

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 321-324

 

Kinetics and mechanism of the oxidation of formic and oxalic acids by tetrabutylammonium tribromide

 

Jaya Gosain & Pradeep K Sharma

Kinetics and mechanism of oxidation of formic and oxalic acids by tetrabutylammonium tribromide (TBATB) have been studied in 1:1 (v/v) acetic acid-water solutions. The main product of oxidation is carbon dioxide. The reaction is first order with respect to TBATB. Michaelis-Menten type of kinetics has been observed with respect to the reductants. The oxidation of a-deuterioformic acid exhibits a substantial primary kinetic isotope effect (kH/kD = 5.85 at 298 K). The reaction has been studied in solvents of different compositions of acetic acid and water. The solvent composition effect has been analysed using Grunwald-Winstein equation. Suitable mechanisms have been proposed.

 

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 325-329

 

Kinetics and mechanism of dissolution and transformation of chloropinnoite in

water at 293-313K

 

Zhihong Liu, Mancheng Hu, Shiyang Gao & Shuping Xia

 

The influence of temperature (293-313K) and stirring rate on the kinetics of dissolution and transformation of chloropinnoite (2MgO2B2O3MgCl214H2O) in water have been studied. According to the kinetic c-t curve and pH-t curve, the process of dissolution and phase transformation can be divided into three stages: dissolution, transformation induce dissolution, and crystallization stage. The experimental results show that chloropinnoite dissolves incongruently in water. MgCl2 is removed first and then the midproduct(MgOB2O34H2O ) is formed. The final phase transformation product is inderite (2MgO3B2O315H2O). The kinetic equations of dissolution and crystallization have been obtained. The kinetic mechanisms of dissolution and crystallization reactions have been confirmed according to order of reaction, activation energy and effect of stirring.

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 330-332

 

Study on the supramolecular inclusion complex of b-cyclodextrin with retinoic acid

 

Yanling Zhang, Kaijun Liao, Weisheng Liu & Xueyi Ma

Inclusion compound of retinoic acid with b-cyclodextrin has been prepared by coprecipitating method and the structure of resulting product studied by elemental analysis, phase solubility diagram, differential scanning calorimetry (DSC) analysis, FTIR and NMR spectroscopy as well as X-ray diffractometry. Results indicate that the formed supramolecule self-assembles in aqueous solution in the molar ratio 2:1 (host: guest).

 

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 333-338

 

Synthesis and characterization of epoxy resin in the presence of p-acetylbenylidene triphenylarsoniumylide-mercuric chloride complex

 

Saurabh Pandey & A K Srivastava

p-Acetylbenzylidene triphenylarsoniumylide mercuric chloride complex modifies and also has autocatalytic curing properties for epoxy resin. The degree of cure (a), percentage crystallinity and glass transition temperature (Tg) of the modified resin, investigated by differential scanning calorimetry, are 1.03, 91% and 298C respectively. The TGA technique has been used to calculate the activation energy and the order of reaction, which are 97 kJ/mol and one respectively. The SEM analysis shows presence of Hg (40%) in the epoxy resin.

 

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 339-341

 

Synthesis, magnetic and spectral studies of some new mixed-ligand nitrosyl complexes of chromium(I)

 

R C Maurya, A Pandey and R Verma

The synthesis and characterization of some new mixed-ligand nitrosyl chromium(I) complexes (having {CrNO}5* electron configuration) of the general formula [Cr(NO)(acac)2(L)], [where L = benzothiazole (BZT), 2-(2-pyridyl)benzimidazole (PBZL), 2-hydroxymethylpyridine (2-HMP), 3-hydroxymetlylpyridine (3-HMP), o-anisidine (ANS) or N,N'-dimethylaniline (NNDA)] have been carried out. The compounds having chromium(I) in a low-spin d5 configuration have been characterized by elemental analyses, molar conductance, TGA, magnetic measurements, electron spin resonance and infrared spectral studies.

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 342-345

 

Synthesis and characterization of chlorodibenzyltin(IV) complexes with N,N-dialkyl dithiocarbamate ligands and crystal structure of (PhCH2)2SnCl(S2CNMe2)

Handong Yin, Chunlin Ma & Yong Wang

Thirteen chlorodibenzyltin(IV) complexes with N,N-dialkyl dithiocarbamate ligands have been synthesized by the reaction of dibenzyltin dichloride with N,N-dialkyl dithiocarbamates in 1:1stoichiometry and characterized by elemental analysis, UV, IR and 1H NMR. The crystal structure of (PhCH2)2 SnCl(S2CNMe2 has been determined by X-ray single crystal diffraction. The crystallographic data are as follows: triclinic, space group P-1, a=7.5750(15) , b=10.615(2) , c=12.059(2) , a=95.053(3), a=95.539(4),bg=99.113(4), Z=2, V=947.6(3) , Dx=1.600g/ cm-3, m=1.705mm-1, F(000)=456, R1=0.0409, wR2=0.1194(I2s(I). The structures consist of discrete molecules containing five-coordinate tin atoms in a seriously distorted tigonal bipyramidal configuration. The molecules are packed in the unit cell as weakly-bridged dimmers.

 

 

Indian Journal of Chemistry

Vol. 41A, February 2002, pp. 346-349

 

A new single pulse method for the measurements of photosensitized singlet oxygen quantum yield

R Venkatesan, S Tamijselvy, N Periasamy, T M Rajendiran, P S Rao & T S Srivastava

 

A new simpler relative method for estimating photosensitized singlet oxygen quantum yield has been developed. In this method a strong depletion signal is observed when porphyrin (2 mM) and 1,3-diphenylisobenzofuran (DPBF, 500 mM) are irradiated using second harmonic 532 nm Nd-YAG laser pulse and monitored at 410 or 415 nm by a ultraviolet filtered white light. The observed depletion is attributed to the reaction of DPBF with sensitized singlet oxygen. The amplitude of the depletion signal is related directly to the singlet oxygen sensitization yield. Appropriate kinetic equations have been derived to relate the change in the absorbance of DPBF and singlet oxygen quantum yield. The singlet oxygen quantum yields of fifteen porphyrins and metalloporphyrins have been investigated in dimethylformamide solution. The results are compared with the quantum yields obtained by the usual kinetic run experiments. The results are found to match exceedingly well in the two methods.