Thallium Nitrate Research Articles

Room-temperature phosphorescence of dansyl chloride solution in the absence of protective medium and its medium effect

A unique fluid room-temperature phosphorescence (RTP) method, which is different from the RTP methods developed previously and needs no microscopically ordered medium, is developed. The RTP emission of dansyl chloride (DNS-Cl) and its amino acid derivatives can be induced directly in aqueous system by the addition of thallium nitrate as heavy atom perturber and sodium sulfite as deoxygenator, λ ex λ em = 326 574 nm . A good linearity between the RTP intensity and the concentration of DNS-Cl in the range 2.0 × 10 −7−1.0 × 10 −5 mol/l was obtained with a detection limit of 1.9 × 10 −8 mol/l. A comparative study of RTP of DNS-Cl in the presence of cyclodextrins (CDs), surfactant micelle, organic solvent and bovine serum albumin (BSA) has also been carried out. This fluid RTP emission system of DNS-Cl is very transparent and stable, and can be modulated by different organic solvents. The quenching behavior of RTP by BSA presents a satisfactory linearity between the concentration of BSA and I RTP , which can be used in the quantitative analysis of BSA.

Phosphorimetric determination of dipyridamole in pharmaceutical preparations.

Room temperature phosphorescence was applied to the determination of dipyridamole in pharmaceutical preparations. The response was linear in the concentration range 100-1600 ng ml-1. The use of phosphorescence enhancers such as thallium(I) nitrate (external heavy atom), sodium dodecyl sulfate (microemulsion stabilizer) and sodium sulfite (deoxygenation agent) was studied and optimized to obtain maximum sensitivity and adequate selectivity. The determination was performed in 0.026 M sodium dodecyl sulfate, 0.0156 M thallium nitrate and 0.02 M sodium sulfite. The pH value was 11.5, adjusted by adding sodium hydroxide. The phosphorescence was totally developed in 15 min, after that the intensity was measured at lambda ex = 303 nm and lambda em = 616 nm. The recovery of the method was tested on commercial formulations containing dipyridamole. The recoveries obtained were 94.67 +/- 0.58% for Persantin and 96.75 +/- 1.37% for Asasantin. The overall least squares regression method was applied to find the most exact straight line that fits the experimental data. The detection limit according to the error propagation theory was 16.4 ng ml-1. The repeatability and relative standard deviation were also determined according to this theory.

Experimental Studies of the Factors That Influence 1-Naphthaleneacetamide Determination by Micelle-stabilized Room-temperature Phosphorescence

A micelle-stabilized room-temperature phosphorescence (MS-RTP) method was developed for the determination of the phytohormone 1-naphthaleneacetamide residues in fortified pear samples. The proposed method is based on the use of a micellar medium obtained by the surfactant sodium dodecyl sulfate in the presence of thallium nitrate as an external heavy atom salt. To avoid oxygen quenching, sodium sulfite solution was used. To establish the optimum experimental variables, a complete and exhaustive statistical analysis of the experimental data by a multivariate optimization approach was performed. MS-RTP spectra were obtained and successfully used to determine 1-naphthaleneacetamide by the established method without further separation, with a detection limit of 25 ng ml - 1 . The precision (RSD ≤ 2.55%) and recovery (≥ 91.9%) were satisfactory.

Determination of the plant growth regulator β-naphthoxyacetic acid by micellar-stabilized room temperature phosphorescence

This paper presents a method for the determination of the plant growth regulator β-naphthoxyacetic acid (NOA) by micellar-stabilized room temperature phosphorescence with the surfactant Triton X-100 (TX-100) as the micellar medium, thallium nitrate as the heavy atom and sodium sulphite as the oxygen scavenger. A multivariate optimization approach using the blocked cube star design of central composite was carried out. The analytical curve of NOA gives a linear dynamic range of 0.4–3.0 μg ml −1 and a detection limit of 0.13 μg ml −1. A recovery of 93.6% was obtained for 1 μg ml −1 NOA in spiked apple samples.

Solid-substrate and micellar-stabilized room temperature phosphorescence of two anilinonaphthalenesulfonates

Room temperature phosphorimetric studies were made on two important fluorescent probes: 8-anilinonaphthalene-1-sulfonate (ANS) and 6-toluidinylnaphthalene-2-sulfonate (TNS). The two dyes gave proper RTF signals using solid-substrate room temperature phosphorimetry (SS-RTP) and micellar-stabilized room temperature phosphorimetry (MS-RTP) under the experimental conditions described in this article. The SS-RTP signals are observed on filter paper using thallium(I) nitrate as a heavy atom. The MS-RTP emission of the compounds is also measurable in sodium dodecyl sulfate (SDS) micelles by applying sodium sulfite as an oxygen scavenger and thallium(I) nitrate as a heavy atom. Light irradiation for a certain period of time could increase the RTP intensities of ANS and TNS solutions. Our results provide some useful information for the RTP studies of derivatized macromolecules using ANS or TNS as phosphorescent probes.

ChemInform Abstract: A Novel Oxidative Cyclization of 2′‐Hydroxychalcones to 4,5‐ Dialkoxyaurones by Thallium(III) Nitrate.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Oxidative rearrangement of 2′-hydroxychalcones having no substituent at the 3′- and 5′-positions with thallium(III) nitrate in methanol

Oxidation of 2′-hydroxychalcones with no substituents at the 3′-and 5′-positions with thallium(III) nitrate (TTN) in methanol has been studied in detail and the following results obtained. (1) 2′-Hydroxy-4,6′-dimethoxychalcones (1b and 2b) have increased reactivity over their methyl ethers as a result of participation of the 6′-methoxy oxygen atom; the reactivity of 2′-hydroxy-4,4′-dimethoxychalcone 3b however was decreased. (2) The reactions were greatly affected by the substituents on the A and B rings and formed the corresponding 1,2-diaryl-3,3-dimethoxypropan-1-ones (acetal) and/or 2-(α-methoxybenzyl)coumaranones (coumaranone): the oxidative rearrangement was greatly accelerated by methoxy groups at the 4- and/or 2-positions to give an acetal as a main product. (3) Formation of the coumaranone was observed only when the 2′-hydroxychalcones had a methoxy group at the 6′-position and a B ring with weaker electron-donating nature. (4) The ratio of the coumaranones formed in the reaction of 2 with no substituent at the 4′-position was lower than that of 1 which formed quickly a cyclic TTN complex between the 2′-hydroxy and the neighbouring carbonyl groups. Only the reaction of 2′-hydroxy-6′-methoxychalcone 2a afforded the acetal and coumaranone together with a large amount of thallium compounds which were converted into a mixture of the corresponding isoflavone and aurone by treatment with hydrochloric acid. From these results, the mechanism of the reaction was proposed as shown in Schemes 2 and 3.

Studies of the Selective O-Alkylation and Dealkylation of Flavonoids.XX. A Convenient Method for Synthesizing 5,6,7-Trihydroxyisoflavones and 5,6-Dihydroxy-7-methoxyisoflavones.

3', 6'-Bis(benzyloxy)-2', 4'-dimethoxychalcones, which were derived from dibenzyl ether of 3, 6-dihydroxy-2, 4-dimethoxyacetophenone, were oxidatively rearranged with thallium(III) nitrate (TTN) in methanol to give 2-aryl-1-[3, 6-bis(benzyloxy)-2, 4-dimethoxyphenyl]-3, 3-dimethoxypropan-1-ones; these products were converted into 6-hydroxy-5, 7-dimethoxyisoflavones by hydrogenolysis followed by cyclization. The 5-methoxy group in the acetates of the isoflavones was selectively cleaved with 5% (w/v) anhydrous aluminum bromide in acetonitrile to give quantitatively the corresponding 5-hydroxyisoflavones, which were hydrolyzed to 5, 6-dihydroxy-7-methoxy-isoflavones. The acetates were also demethylated to 5, 6, 7-trihydroxyisoflavones with 30% (w/v) anhydrous aluminum chloride in acetonitrile at 70°C for 36-48 h. The spectral properties of these isoflanones were examined and some natural isoflavones were identified.

Determination of the Pesticide Carbaryl by Microemulsion Room-Temperature Phosphorescence in Real Samples.

A room-temperature phosphorescence method for the determination of the pesticide carbaryl is described. The proposed method is based on the formation of a microemulsion obtained by mixing an apolar solvent with the surfactant sodium dodecyl sulfate as the micellar medium in the presence of thallium nitrate as the external heavy atom salt. To avoid the oxygen quenching, a sodium sulfite solution was used. A complete and exhaustive statistical analysis of experimental data by a multivariate optimization approach was performed to establish the optimum experimental variables. Good results have been obtained when the insecticide have been analyzed in synthetic and real samples.

A Facile Synthesis and X-Ray Structure Determination of the First Triptycenocrown Ethers

The synthesis of the first triptycenocrown ethers was achieved by two-step procedure which includes condensation of 9,10-bis(chloromethyl)anthracene with polyethylene glycols to yield the intermediate 9,10-anthracenocrown ethers, and subsequent cycloaddilion of benzyne leading to the title compounds. The structures of 9,10-tnplyceno-25-crown-7 (1) and its thallium nitrate complex (Tl-1) were determined by X-Ray diffraction analysis and NMR spectroscopy.

A facile synthesis and X-ray structure determination of the first triptycenocrown ethers

The synthesis of the first triptycenocrown ethers was achieved by two-step procedure which includes condensation of 9,10-bis(chloromethyl)anthracene with polyethylene glycols to yield the intermediate 9,10-anthracenocrown ethers, and subsequent cycloaddilion of benzyne leading to the title compounds. The structures of 9,10-tnplyceno-25-crown-7 ( 1) and its thallium nitrate complex ( Tl-1) were determined by X-Ray diffraction analysis and NMR spectroscopy.

Solid-surface room-temperature phosphorescence detection of serotonin, tryptamine, and gramine enhanced by inorganic salts and sodium dodecyl sulfate

Room-temperature phosphorescence characteristics of serotonin (5-hydroxytryptamine), typtamine, and gramine ([3-(dimethylaminomethyl)indole]) were studied on low-background paper substrates. Several experimental parameters were optimized for maximum signal intensity. Sodium iodide, thallium(I) nitrate, silver(I) nitrate, and lead(II) nitrate were tested as phosphorescence enhancers. The effect of sodium dodecyl sulfate on the enhancement efficiency of these inorganic salts was also studied. The pH values of the solutions were adjusted to optimize the interaction between analyte molecules and solid substrates. Under the experimental conditions for maximum phosphorescence intensity, working curves ranging from two (gramine) to four (typtamine) orders of magnitude were obtained. Limits of detection at the nanogram level were estimated for the three compounds, showing the potential of solid-surface room-temperature phosphorimetry as a detection technique for biogenic amines.

A Novel Oxidative Cyclization of 2'-Hydroxychalcones to 4,5-Dialkoxyaurones by Thallium(III) Nitrate

A Novel Oxidative Cyclization of 2'-Hydroxychalcones to 4,5-Dialkoxyaurones by Thallium(III) Nitrate

Room Temperature Phosphorescence Characteristics of Indole-3-Propionic Acid, DL-Indole-3-Lactic Acid, and Indole-3-Glycolic Acid on Low-Background Paper Substrate

Room temperature phosphorescence characteristics of indole-3-propionic acid, DL-indole-3-lactic acid, and indole-3-glycolic acid were studied on a low-background paper substrate. The influence of potassium iodide, thallium (I) nitrate, silver (I) nitrate, and lead (II) acetate on the intensities of the analyte signals was evaluated. The effects of sodium dodecyl sulfate and pH conditions were studied as well. The analytical figures of merit were obtained for each compound under experimental conditions for maximum phosphorescence emission. Calibration curves with linear dynamic ranges extended between two and three orders of magnitude and limits of detection at the nanogram level were estimated.

Critical phenomena and new effects in the physical acoustics of solids

Experimental results on the variations of the acoustical parameters of crystal in the vicinity of their critical states are given; these variations represent new effects in the physical acoustics of solid, called acoustic splitting and internal friction oscillations. The new effects are illustrated in potassium nitrite and potassium nitrate, thallium nitrate, ammonium perchlorate, silver azide, and in high-temperature superconductors made from yttrium—barium cuprate. Three types of acoustic splitting are discussed, depending on the nature of the phase transition and other factors. An approach is proposed as a possible means of explaining the observed effects on the basis of the notion of anomalous heterophase fluctuations.

Solid surface room temperature phosphorimetry analysis of yohimbine hydrochloride in pharmaceutical formulations

A new method of analysis for yohimbine hydrochloride pharmaceutical formulations is reported. The phosphorescence characteristics of yohimbine hydrochloride were studied at room temperature employing low background paper substrate. The use of phosphorescence enhancers such as sodium iodide, thallium(I) nitrate, and sodium dodecyl sulfate were optimized to obtain limits of detection at the nanogram level. The interference effects of active ingredients commonly encountered in yohimbine hydrochloride formulations were also evaluated. These included methyl testosterone, strychnine hydrochloride, and tocopherol acetate. The recovery of the method was tested in commercial formulations containing yohimbine hydrochloride and tocopherol acetate. The analyses were performed by both the calibration curve and the standard addition procedure. The recoveries obtained varied from 93.61 ± 3.15% to 101.53 ± 11%. The simplicity, the sensitivity, and the selectivity of the method, associated to the satisfactory recoveries obtained, show the potential of solid surface room temperature phosphorimetry for the analysis of yohimbine hydrochloride formulations.

ChemInform Abstract: A Novel Oxidative Cyclization of 2′‐Hydroxychalcones to 4‐ Methoxyaurones by Thallium(III) Nitrate.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Thallium(III) Salts Mediated Oxidative Cyclization of Arenecarbaldehyde Benzothiazol-2-ylhydrazones to Bridged Head Nitrogen Heterocycles

Abstract Oxidation of arenecarbaldehydebenzothiazol-2-ylhydrazones (4) with thallium (III) acetate in refluxing acetic acid, thallium (III) acetate and thallium (III) nitrate in acetonitrile in presence of p-toluene sulphonic acid afforded 3-aryl-1,2,4-triazolo[3,4-b]benzothiazoles (6) by intramolecular cyclization in high yield. A mechanistic scheme for this transformation has been proposed.

A novel oxidative cyclization of 2′-hydroxychalcones to 4-methoxyaurones by thallium (III) nitrate

An unusual oxidative cyclization of chalcones by thallium (III) trinitrate (TTN) to 4-methoxyaurones has been studied. A key feature of this reaction is the introduction of a methoxyl group into the aurone skeleton. Several reactions have been performed to understand the mechanism and regiochemistry of cyclization.

Study of naphthalene and phenanthrene by microemulsion room-temperature phosphorimetry

The effect of pH on the deoxygenation rate and phosphorescence intensity in microemulsion systems was studied. It was found that more intense room-temperature phosphorescence (RTP) can be obtained and the deoxygenation time can be decreased from more that 30 min to less than 100 s if the pH is maintained in the range 7–7.5. In addition, with increase in sodium sulphite concentration the deoxygenation rate increased. Other conditions such as the concentrations of sodium dodecyl sulphate and thallium(I) nitrate were investigated in detail. For the results, the microemulsion RTP of naphthalene and phenanthrene was improved. Limits of detection of 1.3×10 −7 mol 1 −1 for naphthalene and 7.0 × 10 −8 mol 1 −1 for phenanthrene were achieved.