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Inhibition effect of some hydroxytriazenes on copper in nitric acid medium has been studied using weight loss technique at temperature range between 303 to 343 K. The used hydroxytriazene compounds are 3-Hydroxy-3-phenyl-1-(4-sulphonato(sodium salt) phenyl) triazene(HPST), 3-Hydroxy-3-(3-methylphenyl)- 1-(4-sulphonato(sodium salt) phenyl) triazene(HMMPST), 3-Hydroxy-3-(4-methylphenyl)-1-(4-sulphonato (sodium salt) phenyl) triazene (HPMPST), 3-Hydroxy-3-(3-chloroplenyl-(4-sulphonato (sodiumsalt) phenyl) triazene (HMCPST), 3-Hydroxy-3-(4-chloroplenyl-(4-sulphonato (sodiumsalt)phenyl) triazene (HPCPST). Results reveal that inhibition efficiency increases with increasing concentration of hydroxytriazenes from 0.0005 to 0.002 M in following order HPMPST > HPST > HMMPST > HPCPST > HMCPST. HPMPST compound in 0.002M concentration show maximum inhibition efficiency of ~90 at % 303 K temperature. Effect of temperature on inhibition efficiency and thermodynamic parameters have also been reported. The adsorption of hydroxytriazenes obeyed Langmuir Adsorption Isotherm.

In the present investigation, a series of substituted hydroxytriazenes containing trifluoromethyl group were synthesized via diazocoupling reaction with phenylhydroxylamine. The structure of synthesized hydroxytriazenes has been assigned on the basis of elemental analysis, IR, 1H NMR and mass spectroscopy data. The lipid lowering effect of synthesized compounds was evaluated on triton-induced hyperlipidemia model in adult male Charles Foster rats. Administration of 400 mg/kg body wt. dose of triton WR 1339 causes elevation in total cholesterol, phospholipid, and triglyceride levels and inhibits post-heparin lipolytic activity, which was reversed by hydroxytriazenes. Adose of 100 mg/kg body wt. also inhibits free radical generation of superoxide anions and hydroxyl radicals and lipid oxidation.

The present paper reports removal of chromium from aqueous solution using marble slurry waste material at room temperature. Optimum conditions such as concentration of Cr(III) and adsorbent, solution pH, stirring time, effect of foreign ions, and effect of temperature were studied. The adsorption of Cr(III) ion onto marble slurry is well described by Langmuir and Freundlich adsorption isotherm. The maximum Cr(III) removal was 139.92 mg of Cr(III) per gram of marble slurry as evaluated from Langmuir isotherm. Thermodynamic parameters like enthalpy, entropy, and Gibbs free energy have been found to be 30.92 kJ/mol, 118.14 J/mol K, and −4.21 kJ/mol, respectively. These parameters indicated that the process was spontaneous and endothermic in nature. It has been found that 1 g/L marble slurry is capable to remove ≈100% of Cr(III) ions in the pH range of 5–10.

Hydroxy-3-n-propyl-1-(4-sulphonamidophenyl)triazene has been used for spectrophotometric determination of Nickel(II) at 400 nm, keeping the pH between 6.9 to 7.3. The Beer's law is obeyed in the range 1x10-5 to 6x 10-5 M. The molar absorptivity and Sandell's sensitivity values are 6743 dm 3 mol -1 cm -1 and 8.61 ng cm -2 , respectively. The Nickel (II) has been determined successfully even in presence of upto 100 ppm of various interfering cations and anions. The reagent forms complex with iron at ratio of 1:2. The composition of complex was determined by Job's method and Mole ratio method of Yoe and Jones. The value of log ² found from two different methods were 9.57 and 9.53 respectively.

p-Chlorophenylazo-bis-acetoxime has been used for spectrophotometric determination of nickel (II) at 375 nm and a pH of 7.3-8.1. Beer‘s law is obeyed in the range of (1.0-6.0) × 10 -5 M. The molar absorptivity and Sandell’s sensitivity values are 5,389 L mol-1 cm-1 and 10.89 ng cm-2 respectively. Value of log â is determined by two different method i.e. Harvey and Manning’s method and Purohit’s method and the values of it are 9.36 and 9.37 respectively. Hydroxytriazenes have been used as analytical reagents for a number of transition metals. Similar compounds arylazobis-acetoximes developed by Bamberger and subsequently used by Sogani and Bhattacharaya as spectrophotometric reagents for determination of various transition metals such as cobalt, iron and copper. In the present paper p-chlorophenylazo-bis-acetoxime (p-CPABA) has besen used for spectrophotometric determination of nickel (II).

Department of Chemistry, M. L. Sukhadia University, Udaipur-313 00 I, India E-mail : akumargoswami@rediffmail.com Manuscript received 8 April 2002, revised II February 2003, accepted 4 March 2003 p-Sulfonamidophenylazobisacetoxime has been used for spectrophotometric determination of iron(III) at 405 nm, keeping the pH at 2.5-3.0. Beer's law is obeyed in the range (4 to 24) x 10-5 M. The molar absorptivity and Sandell's sensitivity values are 1853 dm3 mol-1 cm-1 and 30.14 ng cm-2, respectively.

The present paper reports synthesis, characterization, spectrophotometric studies and activity prediction of HPMPT with Fe (III) complexes. It was observed that Fe (III) forms complex with HPMPT in 1:3 ratio at wavelength of 510 nm and between the pH range of 4.3–4.8. The molar absorptive and Sandell's sensitivity values are 52175 L mol−1 cm−1 and 1.32 ng cm−2 respectively. The study shows that metal chelates are better in activity as compared to their respective ligands. The results have been interpreted in terms of tables, figures and theories.

The coordination behaviour of azomethines derived from salicylaldehyde and some well known sulpha drugs, viz. sulphathiazole, sulphisoxazole, sulphaphenazole, sulphapyridine, sulphadiazine and sulphaguanidine has been systematically studied. The resulting complexes have been subjected to elemental analyses, conductance measurements, molecular weight determination and electronic infrared and proton nuclear magnetic resonance spectral studies and their plausible structures have been discussed.

The present paper describes the synthesis and structural features of the silicon complexes with S-benzyldithiocarbazate Schiff bases. The resulting complexes of the type, Si(OAc)4–2Ln (where L is the dianion of the ligand and n = 1 or 2) have been characterized on the basis of elemental analyses, molecular weight determinations and conductivity measurements. The nature of bonding has been further discussed on the basis of IR and 1H NMR spectral data. The covalent bonding of oxygen and sulphur with silicon and a dative bond between silicon and nitrogen indicate trigonal bipyramidal and octahedral geometries for Si(OAc)2L and SiL2 type of derivatives, respectively. A few representative complexes have also been screened for their fungicidal as well as bactericidal activity and found to be quite active in this respect.