008979   Pang X Y;You T T (NO, College of Chemistry and Environmental Science, Baoding, 071002, People' Republic of China, Email: pxy833@163.com) : Preparation of biodiesel through transesterification of animal oil and alcohol under the catalysis of SO^2-₄/TiO₂. E J Chem 2009, 6(1), 189-95.

Biodiesel was obtained through transesterification of animal oil and ethanol under the catalysis of SO^2-₄/TiO₂. The activation of SO^2-₄/TiO₂ prepared under different dipping vitriol concentration, baking activation temperature. The optimum conditions to prepare SO^2-₄/ TiO₂ are; dipping vitriol concentration of TiC₄ hydrolysis product is 1.5 mol / L, baking activation temperature for this catalyst takes 500°C. It can guarantee the catalyst has a smaller size and a higher load of vitriol. With animal oil as raw materials, ethanol as transesterifying agent and SO^2-₄/ TiO₂ as catalyst, the influence of reaction time, mass ratio of ethanol to oil and the dosage of catalyst were investigated. Optimum condition to obtain biodiesel was studied through orthogonal experiment, and it is listed as follow: mass ratio of ethanol to oil is 1.5: 1.0, dosage of catalyst is 30 g SO^2-₄/ TiO₂ versus per 100 g animal oil, and reaction time is 8.0 h when reaction temperature is controlled as 80°C. The yield of biodiesel is 0.796 g/g under the above condition. SO^2-₄/ TiO₂ can be used as an effective catalyst during transesterification of animal oil and ethanol, and it can be reused.

6 illus, 2 tables, 16 ref

008978   Nowduri A;Adari K K;Nageswara Rao G; Parvataneni V (Inorganic and Analytical Chemistry Dep, School of Chemistry, Andhra University, Visakhapatnam-530 003, Email: vani_chem@rediffmail.com) : kinetics and mechanism of oxidation of L-cystine by hexacyanoferrate(III) in alkaline medium. E J Chem 2009, 6(1), 93-8.

Kinetics of oxidation of L-cystine by hexacyanoferrate(III) was studied in alkaline medium at 30°C. The reaction was followed spectrophotometrically at λmax = 420 nm. The reaction was found to be first order dependence each on [HCF(III)] and [cystine]. It was found that the rate of the reaction increases with increase in [OR]. The oxidation product of the reaction was found to be cysteic acid. A plausible mechanism has been proposed to account for the experimental results.

3 illus, 1 table, 21 ref

008977   Nithya R;Nithiyanantham S;Mullainathan S; Rajasekaran M (Physics Dep, Selvam College of Arts and Science, Namakkal. Tamil Nadu, Email: nithu59@rediffmail.com) : Ultrasonic investigation of molecular interactions in binary mixtutres at 303 K. E J Chem 2009, 6(1), 138-40.

The ultrasonic velocity, density and viscosity at 303 K have been measured in the binary systems of with benzene and o-xylone with benzene. The acoustical parameters such as adiabatic compressibility, free length, free volume and acoustical impedance are calculated. The results are interpreted in terms of molecular interaction between the components of the mixtures.

1 table, 18 ref

008976   Nath M A;Ganaie N B;Rastogi R P;Peerzada G M (Chemistry Dep, University of Kashmir, Srinagar-190 006, Email: nath_Masood@yahoo.co.in) : Effect of position and number of hydroxyl groups on the oscillatory behaviour of isomers of hydroxybenzoic acid. E J Chem 2009, 6(1), 133-7.

The effect of isomers of hydroxybenzoic acids with respect to their oscillatory behaviour as organic substrates with inorganic bromate and manganese(II) ion as catalyst in aqueous acid medium (1.0 M H₂SO₄) have been studied. The number and the relative position of hydroxyl groups (-OH) in the aromatic ring is found to influence the oscillatory behaviour. Besides, the role of bromination reaction and the formation of corresponding bromoderivative is found to be an important step. The experimental findings are within the purview of Field, Koros and Noyes (FKN) mechanism.

1 illus, 1 table, 20 ref

008975   Moudgil H K;Jyoti (Chemistry Dep, Ch. Devi Lal Univ, Sirsa, Haryana) : Acoustic study of acetone and water in DMSO at 303.15K. Asian J expl Chem 2008, 3(1-2), 100-5.

Ultrasonic velocity (v) and density of binary mixtures of acetone and water in DMSO of different composition was measured at 303.15K. Parameters such as isentropic compressibility K_s, intermolecular free length L relative association R_A acoustic impedances Z, Coefficients A_p standard deviations σ(Y^E) and molar sound velocity R_m were derived using ultrasonic velocity and density for these binary mixtures. Theoretical values of ultrasonic velocity calculated from FLT (Free Length Theory), CFT (Collision Factor Theory), Nomoto's and Van Dael and Vangeel's relation were compared with experimental values of ultrasonic velocity for above said binary mixtures. Nomoto's relation provides best results for experimental ultrasonic velocity of the systems under study. The mixing of DMSO with water tends to break the hydrogen bond present between the water molecules with subsequent increase in ΔK_s and V^E.

2 illus, 5 tables, 54 ref

008974   Morteza S (Faculty of Chemistry, Bu-Ali Sina Univ, Hamadari, Iran, Email: Mshiri@basu.ac.ir) : Metal dodecyl sulfates: combined lewis acid-surfactant catalyst (LASC). Res J Chem Envir 2007, 11(2), 74-5.

Metal dodecyl sulfates known as "combined Lewis acid-surfactant catalyst (LASC)" act in dual role both as a catalyst to activate the substrate molecules and as a surfactant to increase the concentration of organic reactants to form micelle particles in water.

6 ref

008973   Monajjemi M;Naderi F;Aghaie H;Yari M;Mansoor Dalili N;Afsharnezhad S;Mollaamin F (Chemistry Dep, Science and Research Campus, Islamic Azad Univ, Ponak, Hesarak Tehran, P.O. Box: 14155-775, Iran, Email: m_monajjemi@yahoo.com) : Study of thermodynamic functions values for CTAB. Res J Chem Envir 2007, 11(2), 56-62.

The strong association of DNA to CTAB containing vesicles, CTAB is widely used in model systems. Cetyl Trimethyl ammonium bromide as a cationic surfactant and also CTA (Cetyl trimethyl ammonium) were studied. After optimization, the values of thermodynamic functions, chemical shifts and Mulliken charges were obtained by Freq and NMR calculations in Gaussian program. Good results were obtained corresponding the experimental data.

13 illus, 3 tables, 10 ref

008972   Mojumdar Subhash C;Capek I;Capek P;Lenka F; Dusan B (Chemical Engineering Dep, Waterloo Univ, 200 Univ Ave. West, Waterloo, ON N2L 3G1, Canada) : Preparation of composite nanoparticles on the base of starch. Res J Chem Envir 2007, 11(4), 5-12.

The miniemulsion polymerizations of hydrophobic monomers styrene (St), butyl acrylate (BA) and methyl methacrylate (MMA) in the presence of carboxymethylated starch (CMS) were investigated. The emulsions were stabilized by nonionic emulsifier Tween 20 (Tw 20). The synergistic effect of starch on the particle nucleation and stability is observed at high emulsifier concentration. The strong particle agglomeration and degradation of polymer emulsion was observed in the miniemulsion polymerization of MMA with starch. The robust continuous phase polymerization of MMA is connected with agglomeration of polymer and consequently by the strong agglomeration of polymer particles. The limited water-phase polymerization of styrene (grafting) does not form enough long hydrophobic chains of (grafted) radicals due to which the entry of such radicals is limited as well as the participation of grafted polymer on the particle stabilization. Starch acts as a relatively good (co) stabilizer for the miniemulsion polymerization of BA, a poor stabilizer for the miniemulsion polymerization of St and a coagulative agent for the miniemulsion polymerization of MMA, respectively.

6 illus, 3 tables, 17 ref

008971   Mittal S K;Kumar R;Dogra P;Sharma Harish K (PG Dep of Chemistry, Lovely Professional Univ, Jalandhar, Email: shr_harish@yahoo.com) : Potentiometric determination of terbium (III) ion using zirconium (IV) boratophosphate as an electroactive material. Res J Chem Envir 2007, 11(4), 47-51.

Membranes containing varying compositions of electroactive material and epoxy resin as binder were prepared and it is seen that the one having composition 60% ZrBP and 40% epoxy resin exhibits best performance. It shows excellent response in the concentration range of 10^-4 M to 10^-1 M Tb (III) ion with super-Nernstian slope of 45 mV/decade. It has fast response time of 15 seconds. Effect of internal solution was studied and the electrode was successfully used in partially non-aqueous medium. The proposed sensor revealed good selectivity with respect to alkali, alkaline earth, some transition and rare earth metal ions and can be used in the pH range of 2.0-10.0. It was used as an indicator electrode in the Potentiometric titration of Tb (III) ion against EDTA.

5 illus, 2 tables, 24 ref

008970   Mishra A;Sanja D;Sanghani A;Godhani D R (Chemistry Dep, Bhavnagar Univ, Bhavnagar, Gujarat) : Investigation of inhibition property and the trend of inhibition capacity of anisidine on 1060 aluminium alloy in trichloroacetic acid. Asian J expl Chem 2008, 3(1-2), 36-40.

The Inhibition of Corrosion of Aluminium alloy 1060 in aqueous solution of trichloro acetic acid and trend of the maximum inhibition trend of anisidine was measured by weight loss method, in relation to the concentration of corroding media, period of immersion of Aluminium alloy at different temperature range from 25 to 45°C with respect to the concentration of inhibitor and for the support corrosion potential and polarization behaviour are also observed.

1 illus, 5 tables, 27 ref

008969   Majid R (College of Chemistry, Bu-Ali Sina Univ, Hamadan 6517838683, Iran, Email: mj-rezaeivala@basu.ac.ir) : Metalloporphyrins as catalyst in organic synthesis. Res J Chem Envir 2007, 11(4), 80-1.

Metalloporphyrins are important catalysts which can increase rate and selectivity of many organic reactions.

9 ref

008968   Lokhande R S;Sawant A D;Barhate V D (Chemistry Dep, Mumbai Univ, Vidyanagari, Mumbai-400 098, Email: abhaysawant1965@yahoo.com) : Extractive spectrophotometric determination of palladium(II) with 2-hydroxy 3-nitro 5-methyl acetophenone oxime (HNMA). Res J Chem Envir 2007, 11(2), 70-1.

2-Hydroxy-3-Nitro-5-Methyl Acewphenone Oxime (HNMA) extracts Palladium (II) quantitatively (99.96%) into chloroform from an aqueous solution of pH 0.0 - 4.0 and from 0.1- 1M solution of acetic acid and mineral acids. The chloroform extract shows an intense peak at 430 nm (e _max). Beer's law is obeyed over the Pd (II) concentration range 0.1-10 ng cm^-3. The molar absorptivity is 15796 dm³ mole^{-1cm-1 at 430 nm. Composition of extracted species is found to be 1:2 (Pd : HNMA) by Job's continuous variation and mole ratio method. Interference by various ions has been studied. Proposed method has been applied for determination of Pd (II) in catalyst sample.}

^ssc1 table, 4 ref

008967   Li J T;Meng X T (NO, College of Chemistry and Environmental Science, Hebei University, Baoding-071 002, P.R. China) : Deoximation of ketoximes to ketones with ammonium chlorochromate/montmorillonite K10 in dichloromethane. E J Chem 2009, 6(1), 156-60.

A convenient, mild and efficient method for oxidative cleavage of ketoximes to their parent carbonyl compounds with ammonium chlorochromate (ACC) I montmorillonite K1O in dichloromethane at room temperature is described.

2 tables, 19 ref

008966   Kumar S;Garg M;Chundawat N S;Jodha J S;Patel P;Goswami A K (Chemistry Dep, M.L. Sukhadia University, Udaipur-313 001, Email: akumargoswami@rediffmail.com) : Application of hydroxytriazenes in corrosion protection of brass. E J Chem 2009, 6(1), 257-60.

Three hydroxytriazenes have been screened for their inhibitive action against corrosion of brass in ammoniacal environment. They have been found to possess 31.43 to 80.77%. Percentage inhibitive efficiency at 7.5 to 12 N ammonia solutions. The results indicate that hydroxytriazenes can further be explored for corrosion inhibitive property.

1 table, 15 ref

008965   Kumar A;Tyagi S;Sonia (Chemistry Dep, D.A.V. Post Graduate College (C.C.S. Univ), Muzaffarnagar, Uttar Pradesh) : Probe into the dissociation and association behaviour of alkali metal dodecylsulphates in water throgh conductometric investiation (25-45°C). Asian J expl Chem 2008, 3(1-2), 58-63.

The paper deals with the conductometic measurements on aqueous solutions of alkali metal dodecylsulphates represented as LiDS, NaDS, KDS at different temperatures (25-45°C). The specific conductance, K (Scm^-1) as a function of surfactant concentration, C (mol dm^-3) is found to increase at different temperatures, whereas K-C plot intersects to give critical micelle concentration, c.m.c. The cmc for different alkali metals varies as: NaDS > LiDS > KDS and decrease with increasing temperatures. The equivalent conductance at infinite dilution λ_∞ (Scm²/g-eq.) for these solutions is found to increase with increasing temperature and varies as : KDS > LiDS > NaDS. The degree of dissociation (a) for NaDS (0.94 - 0.99), LiDS (0.56- 0.96) and KDS (0.49-0.99) have also been evaluated. The dissociation constant, K_D as (163.0 -1220) x 10^-2, (14.2 -19.1) x 10^-3 and (19.5 - 111.0) x 10^-4 for NaDS, LiDS, KDS, respectively, have been computed. Thermodynamic parameters for dissociation (ΔH°_D < 0, ΔG°_D > 0, TAS¹⁴⁴ < 0) and for association (ΔH°_A > 0, ΔG°_A < 0, TΔS°_A > 0) clearly suggest that the process of micellisation i.e. association predominates over dissociation process for these surfactant systems.

3 illus, 7 tables, 31 ref

008964   Kumar A;Tyagi S (Chemistry Dep, D.A.V. Post Graduate College, (C.C.S. Univ), Muzaffarnagar, Uttar Pradesh) : Probe into the aqueous behaviour of alkaline earth metal dodecylsulphates through density measurements (25-45°C). Asian J expl Chem 2008, 3(1-2), 14-19.

The density measurement, ρ(gcm^-3) for aqueous solutions of dodecylsulphates of Ba, Sr, Ca, Mg [abbreviated as Ba(DS)₂, Sr(DS)₂, Ca(DS)₂, Mg(DS)₂ ] at different temperatures (25-45°C) has been used to evaluate various parameters which might throw light on different aspects of solution behaviour. The critical micelle concentration (c.m.c.), as obtained from ρ-C plots, is found to decrease with increasing metal size and increasing temperature. Density for these solutions increases with increasing surfactant concentration and decreasing temperature. The ρ values for these compounds however vary as : Ca(DS)₂ > Sr (DS)₂ > Mg(DS)₂ > Ba(DS)₂. Partial molar volume (ε°_v) and experimental limiting slope (S_v) as determined from Masson's equation provide information on solute-solvent and solute-solute interactions, respectively. Apparent molar volume (ε_v) is found to increase with increasing concentration and increasing temperature.

3 illus, 8 tables, 26 ref

008963   Kumar A;Tarun (Chemistry Dep, D.A.V. Post Graduate College, (C.C.S. Univ), Muzaffarnagar, Uttar Pradesh) : Viscometric measurements on aqueous dodecylsuphate solutions of Cu (II), Zn (II), Ag(I), Cd(II) at different temperatures (30-50°C). Asian J expl Chem 2008, 3(1-2), 28-32.

The study deals with the viscometric measurements on aqueous solutions of transition metal [Cu(II), Zn(II), Ag(I), Cd(II)] dodecylsulphates at different temperatures (30-50°C). The plots of Viscosity coefficient, η as a function of surfactant concentration, C (mol dm^-3) are found to intersect at a definite concentration indicating the critical micelle concentration (c.m.c.). Viscosity of these solutions is found to increase with increasing concentration, but decrease with increasing temperature. The knowledge of thermodynamic parameters of viscous flow suggests that only the change in enthalpy (ΔH<0) favours the viscous flow whereas both the change in entropy (AS<0) and the change in free energy (ΔG>0) resist the flow in these aqueous surfactant systems.

1 illus, 7 tables, 17 ref

008962   Kumar A;Sonia;Tyagi S (Chemistry Dep, D.A.V. Post Graduate College, (C.C.S. Univ), Muzaffarnagar, Uttar Pradesh) : Dissociation/association behaviour of aqueous alkaline earth metal dodecylsulphates at various temperatures. Asian J expl Chem 2008, 3(1-2), 1-5.

The specific conductance, k (mS cm^-1) of the aqueous solutions of alkaline earth metal (Ba/Sr/Ca/Mg) dodecylsulphates, i.e., Ba(DS)₂, Sr(DS)₂,Ca(DS)₂, Mg(DS)₂ has been measured (25-45°C). The critical micelle concentration (c.m.c.), limiting equivalent conductance at infinite dilution (μ₀), degree of dissociation (a) and dissociation constant (K_D) have been evaluated for these solutions. The significant thermodynamic parameters like enthalpy/free energy and entropy changes have been computed for both dissociation and association processes which are only peculiar to anionic surfactant solutions.

3 illus, 6 tables, 21 ref

008961   Kumar A;Maan S;Tyagi S (Chemistry Dep, D.A.V. Post Graduate College, CCS Univ, Muzaffarnagar, Uttar Pradesh) : Integrated study on solubility, solubilization and pH of aqueous transition metal dodecylsulphates. Asian J expl Chem 2008, 3(1-2), 50-4.

The study deals with the measurements on solubility, solubilization and pH of aqueous transition metal [Cr(II), Mn(II), Fe(II), Co(II)] dodecylsulphates. The dissolution of these compounds in water has been found to be endothermic. The observed variation of solubility (mol dm^-3) for different compounds is as: Cr(II)DS > Co(II)DS > Mn(II)DS > Fe(II)DS. The observed common Krafft point is 40°C, which is obtained as inflection point in log S vs 1/T plots. Thermodynamic parameters for dissolution i.e., ΔH_SOL (kJ mol^-1) and ΔS_SOL (JK^-1 mol^-1) have been computed for these systems below and above the Krafft point. The spontaneous dissolving of a normally water insoluble substance with the help of a surfactant is termed solubilization. The observed maximum additive concentration (MAC) suggests that the solubility of 1 -butanol and 2-methyl-1-propanol in water increases in presence of these surfactants. Sigmoid plots of MAC vs concentration are only in agreement with solubility vs. temperature plots for endothermic dissolution. It is observed that the plots of pH vs concentration indicate a rapid fall in pH upto the critical micelle concentration, cmc. The results suggest that the hydrolysis of these compounds occur mainly at lower concentration (premicellar region) and that the hydrolysis is subdued as the surfactant concentration increases while becoming almost negligible in the vicinity of c.m.c.

3 illus, 5 tables, 28 ref

008960   Khaniani Y;Badiei A (School of Chemistry, University College of Science, University of Tehran, Tehran, Iran, Email: abadiei@khayam.ut.ac.ir) : Linnett double quartet theory, challenging the pairing electrons. E J Chem 2009, 6(1), 169-76.

Linnett proposed his theory 45 years after Lewis's supposition. During these years Pauling, Mulliken and Hund made different molecular structure models based on valance bond and molecular orbital theory. theories were seemed to fit many experiences but had some inabilities. Linnett's double quartet theory could solved some important problems about stability of radicals, paramagnetism / diamagnetism in molecular systems, electronic structure in transition states and finally challenge of resonance and aromaticity. Some basic ideas and concerpts concerning different models and then we give a detailed discussion of the LDQ and use it in diverse branches of chemistry.

12 illus, 9 ref

008959   Kavran Belin G (Chemistry Dep, Geneva University, Laboratory of Mass Spectrometry, Boulevard d'Yvoy 16, CH-1221 Geneva-4, Switzerland) : Investigation of Hopanoid biomarkers in lake sediments by GC-MS and RP-HPLC-APCI-MS. E J Chem 2009, 6(1), 77-88.

Hopanoids are mainly derived from bacteriohopanpolyols that occur especially in bacteria, show the importance of bacterial lipid contributions in geological materials. In this work, GC-MS and RP-HPLC-APCI-MS analyses of hopanoid biomarkers in oxic and anoxic sediment samples from Lake Cadagno (Swiss Alps) and Lake Voua de la Motte (Haute Savoie, France) are presented and discussed. Samples were ultrasonically extracted, fractionated by flush chromatography on silica gel and derivatised before the analyses. Periodic acid/ sodium borohydride cleavage was used to identify highly functionalised hopanoids.

6 illus, 24 ref

008958   Kaur P P;Gupta U (Chemistry Dep, Punjabi University, Patiala-147 002, Email: ushagupta_doc@yahoo.co.in) : H-point standard addition method for simultaneous determination of maneb and zineb. E J Chem 2009, 6(1), 106-12.

The H-point standard addition method (HPSAM) has been applied for simultaneous determination of maneb and zineb using 1-(2-pyridylazo)-2- naphthol (PAN) as a reagent. Both maneb and zineb form wine red colored complex with PAN at pH 9.2 which are soluble in Triton X-l00. Zineb and maneb can be determined simultaneously in the range of 0.414-3.446 fig mL^-1 and 0.663-3.316 fig mL^-1 respectively with satisfactory accuracy and precision. The proposed method has successfully been applied for the simultaneous determination of maneb and zineb in several synthetic samples, spiked water samples and crops.

3 illus, 2 tables, 34 ref

008957   Joseph B;Joseph A (Chemistry Dep, Calicut Univ, Caliut Univ P.O.-673 635, Kerala, Email: drabrahamj@gmail.com) : Indirect complexometric determination of mercury (II) using DL-pencillamine as a demasking reagent.. Res J Chem Envir 2007, 11(2), 49-52.

A rapid, sensitive and selective complexometric method of determination of mercury(II) in the presence of other ions based on the technique of masking and demasking using DL-pendllamine is described. Mercury(II) present in the aliquot is first complexed with a known excess of EDTA and the surplus EDTA is titrated back with lead nitrate solution at pH 5-6 using xylenol orange as indicator, A known excess of 1% solution of DL-pencillamine is then added. The mixture is shaken well and the EDTA released from Hg-EDTA complex is titrated against the standard lead nitrate solution. Accurate and reproducible results are obtained for 4.01-60.15 mg of mercury(II) with relative error ± 0.25% and standard deviation is <0.06 mg. The interference of various ions is also studied. This method was applied to the determination of Mercury(II) in its complexes and alloy compositions.

1 illus, 4 tables, 22 ref

008956   Jain S;Hiran B L;Bhatt C V (Chemical Kinetics and Polymer Research Laboratory, Chemistry Dep, University College of Science, Mohan Lal Sukhadia University, Undaipur-313 001, Email: hiranbl@rediffmail.com) : Kinetics and mechanism of the oxidation of lactic acid and mandelic acid by pyridinium chlorochromate in aqueous acidic medium. E J Chem 2009, 6(1), 273-80.

Pyridinium chlorochromate (PCC) act as two electron oxidant in 'kinetic studies of the oxidation of lactic and mandelic acid in acidic medium. The influence of several factors such as acidity, salts, solvent composition and temperature on the reaction rate has been studied. The reaction shows first order dependence with respect to [PCC] and [H⁺]. The various thermodynamic parameters have been evaluated. Products as oxoacids and absence of free radical were confirmed. Suitable reaction mechanism has been proposed.

6 illus, 5 tables, 15 ref

008955   Jain S;Hiran B L;Bhatt C V (Chemical Kinetics and Polymer Research Laboratory, Chemistry Dep, Mohan Lal Sukhadia University, Udaipur-313 001, Email: hiranbl@rediffmail.com) : Oxidation f some aliphatic alcohols by pyridinium chlorochromate - kinetics and mechanism. E J Chem 2009, 6(1), 237-46.

Kinetics of oxidation of some aliphatic primary and secondary alcohols viz. ethanol, propan-1-ol, propan-2-ol, butan-1-ol, butan-2-o1 and 2-methyl butanol by pyridinium chlorochromate (PCC) have been studied in water-perchloric acid medium. The reaction shows first order dependence with respect to pyridinium chlorochromate [PCC] and hydrogen ion [H⁺]. The rate of oxidation decreases with increase in dielectric constant of solvent suggests ion-dipole interaction. Activation parameters have been evaluated. Products are carbonyl compounds and free radical absence was proved. A tentative mechanism has been proposed.

7 illus, 5 tables, 31 ref

008954   Hu X;An T;Zhang M;Sheng G;Fu J (State Key of Organic Geochemistry, Guangdong Key Laboratory of Environmental Resources Utilization and Pr, Guangzhou 510640, China, Email: antc99@gig.ac.cn) : Preparation and photocatalytic activity of Fe<. Res J Chem Envir 2007, 11(4), 13-21.

Nanometer Fe³⁺ doped TiO₂ and TiO₂ / Fe₂O₃ coupled oxides photocatalysts were prepared with different content ferric citrate and different opposite anions of iron using the Ti(SO₄)₂ precipitation method. The precursors of nanometer TiO₂ were analyzed by thermogravimetric and differential thermal analyses (TG/DTA) and both nanometer photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and UV-VIS diffuse reflectance spectrum (DRS). Results showed that the mean size of nanometer TiO₂ in both photocatalysts decreased with the increase in Fe³⁺ doped content. The photocatalytic activities of prepared catalysts were evaluated under UV light irradiation using methyl orange as a mode organic pollutant in water. The results showed that a small amount of iron dopants in TiO₂ crystalline matrix could enhance the photocatalytic efficiency. The prepared TiO₂ samples exhibited even higher photocatalytic activities than that of Degussa P25, the optimal amount of doped Fe³⁺ was 0.05%. However, with increase of iron element amount, at 25% and 50% contents, the nanometer particle becomes the coupled oxides of TiO₂/Fe₂O₃. Moreover, the effect of different doped anions coming from different ferrous salts on the photocatalytic activities of Fe³⁺/ TiO₂ was also investigated, and the best doped opposite anion is found as SO₄^2-.

10 illus, 2 tables, 30 ref

008953   Heasley Victor L;Renfrow Ronald E;Sator Lisa C;Boerneke Jeffrey L;Shellhamer Dalf F (Chemistry Dep, Point Loma Nazarene Univ, San Diego, CA 92106, USA, Email: vheasley@pointloma.edu) : Synthesis of anhydrous, monohydrate and multihydrate 2, 4, 6-trichlororesorcinol. Res J Chem Envir 2007, 11(2), 13-15.

The data presents a convenient synthesis of four forms of 2,4,6-trichlororesorcinol, 3: a rnultihydrate, a monohydrate, a kinetic anhydrous form and a thermodynamic anhydrous form. The multihydrate is prepared initially (using a significantly modified literature procedure) by the reaction of resorcinol, 1, in sulfuryl chloride, SO₂Cl₂, and acetic acid as a catalyst, and the other three forms are made from the multihydrate. Previous to this report, only the monohydrate form of 3 was clearly confirmed in the literature. The anhydrous form has been mentioned in the literature, but authors were unable to repeat this study. The multihydrate form and the kinetic and thermodynamic anhydrous forms of 3 have not been mentioned previously. The four forms of 3 have been identified by an appropriate combination of the following approaches: gas chromatography, infrared spectroscopy, ¹H and ¹³H nuclear resonance spectroscopy, mass spectrometry, and elemental analysis. Melting points are presented for each form; this will improve the literature markedly since a wide range of melting points is reported. Aside from intrinsic interests in the different forms of 3, the ease of preparation of 3 will make a contribution to synthetic chemistry. 2,4,6-Trichlororesorcinol, 3, is also of interest because it is an intermediate on the synthetic pathway of the pentachloro derivative, 2, of resorcinol, 1. Pentachloro derivative, 2, is an important model compound of the humic acids.

1 illus, 13 ref

008952   Fernando D;Carvalho da Silva (Instituto de Qumica, Universidade Federal Fluminense, UFF, CEP: 24020-150 Niteroi, Rio de Janeiro, Brazil, Email: gpofernando@yahoo.com.br) : Organic reactions in superheated water. Res J Chem Envir 2007, 11(2), 72-3.

At high temperatures and pressures, pure liquid water becomes a surprisingly effective medium for the reactions of organic compounds.

12 ref

008951   Fanny G (Laboratoire de Chimie des Molecules Bioactives et des Aromes, Universite de Nice-Sophia Antipolis, CNRS, UMR 6001 - Parc Valrose - F 06108 NICE Cedex 2 - France., Email: grau@unice.fr) : Metallic triflimidates: green lewis acids catalysts. Res J Chem Envir 2007, 11(2), 76-7.

Typical Lewis acid catalysts can be advantageously replaced by metallic triflimidates which exhibit superior activity and efficiency.

9 ref

008950   Desale Bhatu S (NO, Arts Science and Commerce College, Manmad-423 104, Email: bsdesale@yahoo.com) : Volume and transport properties of binary liquid mixtures of propyl acetate with butan-1-ol and hexan-1-ol at 308.15 and 313.15 K.. Res J Chem Envir 2007, 11(4), 37-41.

The densities and viscosities of binary mixtures of propyl acetate with butan-1-ol, pentan-l-ol and hexan-1-ol have been measured over the entire range of composition at 308.15 and 313.15 K and at atmospheric pressure. Excess Gibbs free energy of activation of viscous flow (G^ΔE) and Grunberg-Nissan interaction parameter (d) of binary liquid mixtures is useful in understanding the nature of intermolecular interactions between two liquids.

3 illus, 3 tables, 15 ref

008949   Desai S A;Dhomane A S (Chemistry Dep, K.V. Pendhakar College, Dombivali (E)., Dist. Thane-421 203, Email: sadesai_28543@yahoo.co.in) : Indirect spectrophotometric determinaton of vanadium (IV). Res J Chem Envir 2007, 11(4), 22-5.

Spectrophotometric method for trace determination of Vanadium (IV) has been developed based on reduction of absorbance of alkaline potassium permangnate solution. Vanadium (IV) gets oxidized by alkaline potassium permangnate solution to Vanadium (V) in presence of barium ion. Hence reaction of Vanadium (IV) results in reduction in optical density of alkaline potassium permangnate solution containing barium ion. This reaction is exploited to develop a simple, rapid and sensitive method for trace determination of Vanadium (IV). The reaction was studied under different conditions and different parameters were checked. The calibration curve, which is a plot of decreasing value of potassium permangnate solution at 540 nm against increasing concentration of Vanadium (IV) is linear up to six ppm.

2 illus, 6 tables, 24 ref

008948   Begum A;Ramaiah M;Harikrishna;Khan I;Veena K (Chemistry Dep, P.E.S. School of Engineering, , Bangalore, Email: drabid.drabida@gmail.com) : Analysis of heavy metals concentration in soil and litchens from various localities of hosur road, Bangalore, India. E J Chem 2009, 6(1), 13-22.

Assessment of heavy metal content in litchens and soil samples from various localities of Hosur Road, Bangalore south was undertaken. Topsoil samples (0-10 cm) were taken at various locations, the metals analysed were Cr, Pb, Fe, Zn, Ni and Cu. The geoaccumulation index of these metals in the soils under study residential areas indicated that they are uncontaminated with Ni, Zn, and Fe and moderately contaminated with Cr and Pb. In Industrial areas and traffic junctions the concentration of Fe, Pb and Ni was maximum. Heavy metal accumulation in few prominent lichens of some localities was analysed. Cr and Pb were maximum in Chrysothrix candelaris (L.) Laundon, at the gardens of Madiwala and Silk Board junction with 95.29 and 623.95 μg g^-1 dry weight respectively. Fe and Cu were maximum in Bulbothrix isidiza (Nyl.). Hale and Pyxine petricola Nyl at Central Prison campus and Kendriya Sadan campus with 22721 and 338.12 μg g^-1 dry weight respectively, Lecanora perplexa Brodo at Infosis and Wipro Campus, electronic city have 531.5 and 634 μg g^-1 dry weight of Zn. While Ni and Fe were maximum in Arthopyreniaceae at Shanti Niketan of MICO Limite.d with. 1100 and 23200 μg g^-1 dry weight respectively.

3 illus, 4 tables, 11 ref

008947   Baviskar B A;Baviskar B;Shiradkar M R;Deokate U A;Khadabadi S S (Pharmaceutical Chemistry Dep, Government College of Pharmacy, Amravati-444 604, Email: bhushan_baviskar@rediffmail.com) : Synthesis and antimicrobial activity of some novel benzimidazolyl chalcones. E J Chem 2009, 6(1), 196-200.

Some novel benzimidazolyl chalcones were synthesized by condensation of N-(4-(lH-benzo[d]imidazol-2-yl)phenyl)acetamide with aromatic aldehydes in presence of aqueous potassium hydroxide solution at room temperature. All the synthesized compounds were characterized on the basis of their IR, ¹H NMR spectroscopic data and elemental analysis. All the compounds have been screened for antimicrobial activity by the cup-plate method.

3 tables, 16 ref

008946   Anil Kumar;Tarun;Tyagi S (Chemistry Dep, D.A.V. Post Graduate College, C.C.S. Univ, Muzaffarnagar, Uttar Pradesh) : Probe into the dissociation and association behaviour of aqueous transition dodecylsulphates (30-50°C). Asian J expl Chem 2008, 3(1-2), 94-9.

The dissociation and association behaviour of aqueous transition metal (copper, zinc, silver, cadmium) dodecylsulphates, abbreviated as Cu(II)DS, Zn(II)DS, Ag(I)DS, Cd(II)DS,has been thoroughly examined using conductance measurements. The specific conductance, k(Scm^-1) for these solutions is found to increase with increasing concentration (mol dm^-3) and increasing temperature. The breaks in k-C plots give the values for critical micelle concentration, cmc. It is noticeable that cmc increases with increasing temperature. The data for degree of dissociation, a and dissociation constant, K_D for Ag(I)DS suggest greater tendency for dissociation as compared to Cu(II)DS,Zn(lI)DS,Cd(II)DS systems. Also observed that dissociation process is assisted by negative enthalpy and increase in entropy,(ΔH°_D < 0 and TΔS°_D > 0), whereas the process for micellisation or association is supported by free energy decrease and entropy increase (ΔG°_A < 0 and TΔS°_A>0).

1 illus, 5 tables, 30 ref

008945   anil Kumar;Maan S;Tyagi S (Chemistry Dep, D.A.V. Post Graduate College, C.C.S. Univ, Muzaffarnagar, Uttar Pradesh) : Rheology, density and molar volume of aqueous transition metal dodecylsulphates. Asian J expl Chem 2008, 3(1-2), 82-91.

The apparent molar volume, φ_v (cm³mol^-1) and fluidity, φ (P^-1 or rhe) for the aqueous solutions of transition metal [Cr(II), Mn(II), Co(II)] dodecylsulphates at different temperatures (30°-50°C) have been evaluated from the data of density, p (g cnr^-3) and viscosity, t|(P), respectively. The limiting apparent molar volume, φ°_v(cm³ mol^-1) has been computed employing Masson's equation. Both viscosity and density for these aqueous solutions are found to increase with increasing surfactant concentration. The CMCs determind from η-C and ρ-C plots are in good agreement. The investigation reveals that transition metal dodecylsulphates exhibit a greater tendency to undergo micellization in water even at low surfactant concentration (0.008-0.010 mol dm³). Higher fluidity for these aqueous surfactant solutions is suggestive of the fact that these are free flowing solutions even after the onset of micellization. Partial molar expansibility data, E°surf have been evaluated for these systems utilizing the temperature dependence of partial molar volume, φ°_v. E°_SURF increases with increasing temperature which may be attributed to a decrease in electrostriction as well as loosening of water structure at higher temperatures.

6 illus, 15 tables, 24 ref

008944   Ahmad S;Shawali;Darwish E S S;Altalbawy F M A (Chemistry Dep, Faculty of Science, Cairo Univ, Giza, Egypt, Email: as_shawali@mail.com) : Site selectivity in diazonium coupling of ethyl (3-phenyl-7H-[1,2,4]-triazolo [3,4-b] [1,3,4] thiadiazin-6-yl)acetate and tautomeric structure of the coupling products in ground and excited sates. Asian J Spectrosc 2008, 12(2-3), 113-20.

A series of new ethyl (arylhydrazono)-(3-phenyl-7H-[1,2,4]triazolo[3,4-b] [1,3,4]thiadiazines-6-yl)acetates 4 were synthesized and their electronic absorption spectra were investigated in different organic solvents of varying polarities and their acid dissociation constants in both ground and excited states were determined spectrophotometrically The tautomeric structures of such products were elucidated by their spectral analyses and correlation of their acid dissociation constants with Hammett equation. The results indicated that the studied compounds 4 exist predominantly in the hydrazone tautomeric form 4B in both ground and excited states.

1 illus, 3 tables, 18 ref

008245   Yusuf M;Rupesh Kumar;Bansal W R;Ritu Bala (Chemistry Dep, Punjabi University, Patiala-147 002, Email: dryusufpur@rediffmail.com) : Photocyclisations of some 3-alkoxychromones: Substituent control on photoreactivity. Indian J Chem-Sect B 2007, 46(11), 1860-7.

The photochemical transformation of some 3-alkoxy-2phenylchromones bearing various stabilizing substituents on the 3-alkoxy group have been described. Photoreactions occur through the 1,4-biradicals that yield angular tetracyclic products. The yield and distribution of the photoproducts are dictated by the nature of substituents of 3-alkoxy moieties.

2 illus, 2 tables, 13 ref

008244   Yaoguo W;Xiang L;Sihai H;Yuezhou Z;Dezhong Y (Applied Chemistry Dep, Northwestern Polytechnical Univ, Xi'an 710072, China, Email: wuygal@163.com) : Effect of nitrite on benzene degradation linked to denitrification in riverbed sediments. Res J Chem Envir 2007, 11(3), 13-17.

Microcosm tests were conducted to study the possibility of benzene degradation as well as the effects of nitrite on the degradation linked to denitrification with the coexistence of nitrite and nitrate in riverbed sediments. Although nitrite appeared and even accumulated in some cases, benzene was degraded in the riverbed sediments under denitrification conditions. At certain concentrations, nitrite had the potential to enhance rather than inhibit the degradation. When the initial concentration of total NO₃-N and NO₂^--N was about 250 mg/L, enhancement was greatest when NO₂^--.N was at 186.45 mg/L. When the initial concentration of NO₃-N was 15.5 mg/L, enhancement was greatest when N0₂^--N was at 105.87 mg/L. During all the test processes, the reaction rates and their rate constants for nitrite were greater than for nitrate. This shows that nitrite is more readily used as an electron acceptor to denitrification and aid microbes, and this may be the reason that nitrite has the potential to enhance the degradation. Therefore, nitrite can be used to enhance benzene degradation in riverbed sediments under denitrification conditions, especially when the concentration of nitrate is low.

1 illus, 3 tables, 21 ref

008243   Upmanyu N;Dolly A;Garg G;Mishra P (Pharmaceutical Sciences Dep, Dr. Hari Singh Gour Univ, Sagar-470 003, Email: neerajupmanyu@rediffmail.com) : Nuclear overhauser effect : revolutionary approach in NMR spectroscopy. Res J Chem Envir 2008, 12(1), 101-3.

Nuclear overhauser effect (NOE) is the change in a signal's intensity as the result of perturbation applied to spins other than those associated with that signal. NOE, is therefore, the effect of magnetization transfer through space. NMR is commonly used for characterizing the structure and molecular dynamics of target or ligand molecules. NOE is used for the identification of lead compounds in an NMR screening, preferably in a high throughput manner. Reverse NOE pumping and transferred NOE can be used without isotope labelled protein. Sequential NOE connectivity determines the secondary structure elements. The three-dimensional structure is from NOE connectivity's between secondary structure elements. NOE-based methods not only prove ligand-protein binding interactions, but they can, in addition be used to characterize the binding epitope of the ligand.

^iia1 illus, 25 ref

008242   Tripathi Y B;Pandey N;Tripathi P (Medicinal Chemistry Dep, Institute of Medical Sciences, Banaras Hindu Univ, Varanasi-221 005, Email: yaminiok@yahoo.com) : Purification of nuts of Semecarpus anacardium Linn., a herbal drug for arthritis. Curr Sci 2008, 94(8), 1062-5.

Although nuts of Semecarpus anacardium Linn. (Ana-cardiaceae) (SA nuts) are used in the Ayurveda and Siddha systems of medicine for the management of arthritis and other inflammatory diseases, they are always associated with several side effects, if used un-purified. Several traditional methods for purification are available, but they are not free from toxicity and also the scientific basis behind these purification steps is not known. Here, we have hypothesized that the oily part of the nut is toxic and its degree of removal is proportional to its safety margin. To test this hypothesis, we treated the SA nuts with brick powders (traditional method of Ayurveda), silica gel and hexane solvent for various time periods. These defatted nuts were washed and extracted with ethanol and the solvent-free extract was tested on rat peritoneal macro-phages in terms of NO production, both in the absence and presence of lipopolysaccharides (LPS). Results suggest that the hexane fraction (oily part) is highly toxic and produces free radicals (FR) in a concentration-dependent manner without affecting the cell viability and the hexane fraction works as a prooxidant, similar to that of LPS. Contrary to this, the alcoholic fraction of hexane-washed SA nuts (defatted nuts) significantly scavenged FR and its yield was directly proportional to the removal of the oily part. Thus it is suggested that the oily part of the nuts is prooxidant, whereas the alcoholic fraction is antioxidant, and that the use of hexane is better for purification of SA nuts than the traditional methods, as it enhances the therapeutic value.

3 tables, 21 ref

008241   Teodorova S (NO, Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy o, 72 Tzarigradsko shaussee, 1784 Sofia, BULGARIA, Email: seteodor@tea.bg) : Coupling of chemical reaction and fluxes in open thermodynamic system. Res J Chem Envir 2007, 11(3), 7-12.

A theory of direct coupling of chemistry and diffusion in membranes is not yet developed. The problems concerning open thermodyhamic systems, where chemical reactions proceed and mater exchanges with the surroundings, are especially of interest in context of further applications to biological systems. The paper is a simple effort to consider a possible formulating of a direct dependence between fluxes and chemical reaction proceeding in an open thermodynamic system. The existence of vectorial reciprocal coefficients, coupling chemical reaction and fluxes, when the reaction advances in anisotropic membrane, is discussed. The relaxation of the chemical affinity A to its steady state value is derived for a reaction coupled with fluxes exchanged with the surroundings. Formula of relaxation of the chemical affinity to equilibrium value is obtained as a particular case. The advancement of reaction φ is defined in open thermodynamic systems and it is shown that IE depends not only on the concentrations of the constituents but also on the fluxes. The results obtained could be used in investigations of some irreversible processes in open thermodynamic systems where a linear approximation of the phenomenological laws could be assumed.

16 ref

008240   Swathi R S;Sebastian K L (Inorganic and Physical Chemistry Dep, Indian Institute of Science, Bangalore-560 012, Email: kls@ipc.ernet.in) : Molecular mechanism of heterogeneous catalysis. Resonance 2008, 13(6), 548-60.

Gerhard Ertl, the German physical chemist, was awarded the Nobel Prize in chemistry for the year 2007, for his contributions in the area of surface science. His painstaking work led to a microscopic understanding of heterogeneous catalysis in industrially important chemical reactions. These include the Haber-Bosch process for the production of ammonia, and the catalytic oxidation of carbon monoxide.

4 illus, 10 ref

008239   Subramaniam G;Malarvizhi M (Chemistry Dep, Velammal College of Engg. and Tech., Madurai-625 009) : Synthesis and characterisation of iron (III) complex with 3-carboxy-4 quinolinol. Acta Cienc Indica-Phys 2008, 34(3), 351-5.

Bis (pyridine) (chloro-3-carboxyIate-4-quinolinato) aqua iron (III) complex was synthesized and its IR spectrum was studied. The IR spectra of the ligand 3-carboxy-4-quinolinol was compared with the IR spectra of the metal complex, for the confirmation of the formation of the metal complex as well as to elucidate the structure of the complex.

3 illus, 1 table, 18 ref

008238   Sondhi S M;Jain S;Rani R;Ashok Kumar (Chemistry Dep, Indian Institute of Technology Roorkee, Roorkee-247 667, Email: sondifcy@iitr.ernet.in) : Microwave assisted synthesis of indole and furan derivatives possessing good anti-inflammatory and analgesic activity. Indian J Chem-Sect B 2007, 46(11), 1848-54.

Indole-2-carboxylic acid on condensation with benzene sulfonyl hydrazide and p-toluene sulfonyl hydrazide gives condensation products 1a and 1b. 1H-Tetrazole-5-acetic acid, hydantoin-5-acetic acid, orotic acid, 5-bromo nicotinic acid and indole 2-carboxylic acid have been condensed with furfuryl amine to give corresonding condensation products 2a-e whereas condensation of succinic acid and adipic acid with furfuryl amine gives products 3a and 3b respectively. 3,5- Pyrazole dicarboxlic acid, 4,5-imidazole dicarboxylic acid and 3-carboxy-1,4-dimethyl pyrole-2-acetic acid on condensation with furfuryl amine give compounds 4, 5 and 6. All these compounds i.e. 1a,b, 2a-e, 3a,b, 4, 5 and 6 have been characterized by spectroscopic means and have been screened for anti-inflammatory and analgesic activity. Compounds 2a, and 5 exhibit good anti-inflammatory and 2a, 2e and 5 exhibit good analgesic activity.

2 tables, 17 ref

008237   Saini A;Sanjay Kumar;Sandhu J S (NO, Punjabi University, Patiala-147 002, Email: j_sandhu2002@yahoo.com) : Gallium(III) halides catalyzed, microwave enhanced, synthesis of 3,4-dihydropyrimidin-2-(1H)-ones under solvent free condition. Indian J Chem-Sect B 2007, 46(11), 1886-9.

Gallium(III) halides catalyzed and microwave enhanced thee component Biginelli reaction of aldehyde, 1,3-dicarbonyl compounds and urea or thiourea under solvent free conditions to afford 3,4-dihydropyrimidin-2-(1-H)-ones in excellent yields is described. the present procedure for the production of dihydropyrimidinones describes the first ever catalytic activity of gallium (III) halides. This improved procedure is fairly simple, facile and environment friendly.

1 illus, 1 table, 22 ref

008236   Reena Devi L;Singh T S; (Chemistry Dep, Manipur University, Canchipur-795 003, Email: warjeet@yahoo.com) : Antifungal and phytochemical studies of Eupatorium birmanicum DC.. Indian J Chem-Sect B 2007, 46(11), 1868-72.

The isolation of coumarin, β-sitosterol and β-sitosterol-D-glucoside from the chloroform extract; and o-coumaric acid, cerebroside 1, ceramide 2, and quercetin-3-o-rutinoside 3 from the methanol extract of the leaves of Eupatorium birmanicum DC. along with the antifungal study of the chloroform and methanol extracts from the plant are reported. The structures of the isolated compounds are characterized by different spectroscopic methoids.

2 tables, 8 ref

008235   Rao K;Sahu N;Panigrahi P K (Theoretical Physics Div, Physical Research Laboratory, Ahmedabad-380 009, Email: kumar@prl.res.in) : Fermion number fractionization. Resonance 2008, 13(8), 738-51.

Solitons emerge as non-perturbative solutions of non-linear wave equations in classical and quantum theories. These are non-dispersive and localised packets of energy - remarkable properties for solutions of non-linear differential equations. In the presence of such objects, the solutions of Dirac equation lead to the curious phenomenon of 'fractional fermion number'. Under normal conditions the fermion number takes strictly integral values. Describes accidental discovery and its manifestation in poly-acetylene chains, which has led to the development of organic conductors.

2 illus, 6 ref

008234   Ramadevi P;Ramanathan R (Chemistry Dep, V.S.S. Government Arts College, Pulankuruchi, Sivagangai, District-630 413) : Comparative study of IR spectrum of Ni(II) and Cu(II) complexes of 1-phenyl-tetrazoline-5-thione. Acta Cienc Indica-Phys 2008, 34(3), 345-50.

1-Phenyl tetrazoline-5-thione play an important role in industrial applications. The comparative study of these two complexes is meant to analyze the difference in the model of bonding in the vibration spectra which help us to reveal the structural difference between these two complexes. It was predication that these two complexes had slight difference in the IR spectra which is useful tool for the predication of molecular structures. Hence a comparative study of closely related complexes helps in the predication of molecular structure.

5 illus, 1 table, 9 ref

008233   Ram Reddy M J;Arun Kumar P;Srinivas U;Venkat Reddy V;Ram Reddy M J;Rao G V;Jayathirtha Rao V (Organic Division II, Indian Institute of Chemical Technology, Hyderabad-500 007, Email: jrao@iict.res.in) : Wavelength dependent regioselective E→Z isomerization of 9-anthryldiene derivatives. Indian J Chem-Sect B 2007, 46(11), 1833-47.

9-Anthryldiene derivatives 1-5 are synthesized to study E→Z photoisomerization. Photoisomer composition upon direct excitation, and triplet-sensitized isomerization are determined. Quantum yield of isomerization, quantum yield of fluorescence and fluorescence life times are determined for these compounds. Interestingly, upon direct excitation the anthryldiene derivatives 1-3 carrying electron withdrawing end groups (EWG) displayed wavelength dependent regioselective E→Z isomerization from the singlet excited state. Triplet sensitization studies revealed that these anthryldiene derivatives undergo Z→E isomerization and not E→Z isomerization. The dual fluorescence observed for 1, 2, 3 and 2E, 4Z-1, indicates the involvement of two different emissive states. The fluorescence solvatochromism displayed by 1, 2, 3 and 2E, 4Z-1 is a clear indication of the involvement of a highly polarized/charge transfer singlet-excited state and the same is involved in the isomerization process. Fluorescence lifetimes measured for these compounds displayed bi-exponential behaviour supporting the presence of two emissive states. A mechanism for photoisomerization is suggested.

9 illus, 6 tables, 38 ref

008232   Parvin Kumar;Jag Mohan;Makrandi J K (Chemistry Dep, Maharshi Dayanand University, Rohtak-124 001, Email: jkmakrandi@gmail.com) : Heterocyclic systems containing bridgehead nitrogen atom: synthesis and evaluation of bio-activity of thiazolo[3,2-b]-s-triazoles and isomeric thiazolo[2,3-c]-s-triazoles. Indian J Chem-Sect B 2007, 46(11), 1883-5.

Synthesis of 2-(3'-bromophenyl)-5-(p-bromophenyl)thiazolo[3,2-b]-2-triazoles 4 has been achieved starting from the appropriate 5-mercapto-3-(3'-bromo phenyl)-s-triazole 2. Compound 2 on condensation with α-haloketones gives the ketones 3 which on cyclization with PPA afford 5-(p-bromophenyl)-2-(3'-bromophenyl)thiazolo[3,2-b]-2-triazoles 4 and not the isomeric thiazole[2,3-c]-s-triazoles 6. This has been established by an unequivocal synthesis of 6 through POCl₃ cyclization of 3'-bromobenzoylhydrazino-4-p-bromophenyl-thiazole hydrobromide 5. The diuretic, antibacterial and antifungal activities of some of the compounds have also been evaluated.

^sscm14 ref