Pyrylium Perchlorate Research Articles

Fluorescence chemosensor for acetate ion and fluorine ion based on 1,2,4-triazolyl substituted pentaphenylpyridinium

A novel pyridinium salt derivative, 2,3,4,5,6-pentaphenyl-1-(1H-1,2,4-triazol-3-yl)pyridinium perchlorate (1) has been designed and synthesized by using pyrylium perchlorate and 3-amino-1H-1,2,4-triazole as ingredients, which can be exploited for the binding and specific sensing of anion via hydrogen bonds. Compound 1 exhibits intense blue emission in solution with maximum emission at 469 nm with a red shift relative to that (426 nm) of solid state. The luminescence intensity of 1 could be selectively and sensitivity quenched with acetate ion and fluorine ion among various anions including F−, Cl−, Br−, I−, AcO− and NO3−. Furthermore, the possible detection mechanism was investigated. This work could contribute a credible potential sensing application of 1,2,4-triazolyl substituted pentaphenylpyridinium salts towards the specific anions in biological and environmental concerns.

Chemically Modified Electrodes Based on 4-(azulen-1-yl)-2,6-bis ((e)-2-(thiophen-2-yl)vinyl) Pyrylium Perchlorate

The electrochemical behavior of 4-(azulen-1-yl)-2,6-bis((E)-2-(thiophen-2-yl)vinyl) pyrylium perchlorate (L) was studied by cyclic voltammetry, differential pulse voltammetry, and rotating disk electrode voltammetry. The electrochemical polymerization of L was studied. Modified electrodes covered by polyL films were obtained by successive scanning or by controlled potential electrolysis (CPE) at different charges and potentials. The new electrodes obtained by CPE were applied for sensing the following heavy metals ions: Cu(II), Pb(II), Cd(II), Hg(II). The best results have been registered for Pb(II) ion with a detection limit of 10-8 M.

Study of Analytical Parameters of a Differential Pulse Voltammetric Method using Chemically Modified Electrodes for Lead Analysis in Water

The development of a new voltammetric method for the determination of Pb2+ ions in water samples using glassy carbon electrodes modified with 2,6-bis((E)-2-(thiophen-2-yl)vinyl)-4-(4,6,8-trimethylazulen-1-yl)pyrylium perchlorate is here presented. The analytical parameters for differential pulse voltammetry (DPV) were established and the method was applied for Pb2+ ions determination in acetate buffer solution at pH 5.5. For the developed DPV method the linearity of calibration curve was set up between 20.71mg L-1 - 103.6 mg L-1 with a good correlation coefficient R2=0.9988, the intermediate precision was calculated for three lead concentrations:20, 60,100mg L-1.The obtained detection and quantification limits were 3.1 mg L-1, respectively 10.4 mg L-1. An uncertainty budget was developed and the value of expanded uncertainty was assessed. The optimized method was used to analyze Pb2+ ions from of water samples and good correlation with standard method was obtained.

Highly efficient one-pot synthesis of α-free pyrylium salts with tunable fluorescence emission via ring-expanding reaction of triarylcyclopentadienes

A series of α-free pyrylium perchlorates were prepared by one-pot oxidation of substituted cyclopentadiene derivatives in the presence of perchloric acid. A tunable fluorescence with green to red emission in dichloromethane and green to orange emission in the solid state can be achieved by changing the aryl groups on 2- or 4-position of pyrylium ring. Furthermore, single crystal structures and quantum chemistry calculation were conducted to understand the relationship between structures and optical properties.

ChemInform Abstract: Heterocyclic Radical Mediated Synthesis and Fluorescence Properties of Conjugated Polyene Ketones.

AbstractDecatetraene diketone derivatives are prepared in a one‐step procedure from the phenyl‐substituted pyrylium perchlorates.

Heterocyclic Radical Mediated Synthesis and Fluorescence Properties of Conjugated Polyene Ketones

A straightforward route for the preparation of decatetraene diketone derivates is presented. The synthesis has been accomplished by a one-step procedure starting from phenyl-substituted pyrylium perchlorates, and an elaborate heterocyclic α-radical mechanism was proposed. This class of molecules displays a crystallization induced emission enhancement property.

Determination of traces of nitrate in water samples using spectrophotometric method after its preconcentration on microcrystalline naphthalene

Nitrate is quantitatively retained with 2,6-bis(4-methoxyphenyl)-4-phenyl pyrylium perchlorate (PPP) on microcrystalline naphthalene in the pH range of 6.5-9.0 from a large volume of aqueous solutions of various samples. The method was based on the complexation between PPP and nitrate and then, extraction of the resulted complex from aqueous solution by microcrystalline naphthalene. The solid mass consisting of the nitrate complex and naphthalene was then dissolved in dimethyl formamide (DMF) and absorption of the resulted solution was obtained at 328 nm. The linear calibration range for the determination of nitrate was 15-135 μg L-1 with the detection limit of 10 μg L-1.

ChemInform Abstract: Polarographic Reduction of Pyrylium Salts.

Abstract The polarographic reduction of several pyrylium perchlorates in buffered and unbuffered solution was investigated at DME. In 0.1M LiCl-DMF, two waves are observed. The first wave is reversible and diffusion controlled representing the uptake of one electron, whereas the second wave is a catalytic reduction of the perchlorate ion. In buffered solutions (pH ⩽ 5), only one wave is obtained and its i l , decreases with pH due to the partial conversion of the pyrylium salt into a pseudo-base. The rate of conversion, electron affinities, ionization potentials and the energy levels of HOMO and LUMO of these compounds have been computed and a linear correlation shown to exist between the spectroscopic data and the redox potentials.

ChemInform Abstract: Reactions of 3-Acetyltropolone with Benzaldehydes in Trimethyl Orthoformate in the Presence of Perchloric Acid: Synthesis of 2-Aryl-4-methoxy-9-oxocyclohepta[b]pyrylium Perchlorates.

3-Acetyltropolone (1) reacted with benzaldehydes in trimethyl orthoformate in the presence of perchloric acid to afford 2-aryl-4-methoxy-9-oxocyclohepta[b]pyrylium perchlorates 3a-c in 25–37% yields. From the filtrates, 3-(3,4-diaryl-3-butenoyl)tropolones 4a,b and 3-(2-methoxycinnamoyl)tropolone (5) were also isolated.

Sol–gel derived highly selective optical sensor for sensitive determination of the mercury(II) ion in solution

We report a versatile optical sensor by incorporating the indicator dye 4-phenyl-2,6-bis(2,3,5,6-tetrahydrobenzo[b][1,4,7]trioxononin-9-yl)pyrylium perchlorate into a sol–gel layer. The proposed optical sensor that is stable, fast and highly selective to Hg 2+ ions shows a significant absorbance signal change on exposure to an aqueous solution containing mercury(II) ion. The sensing film is able to determine mercury(II) ion in aqueous solution with a high selectivity over a wide dynamic range between 1.52 × 10 −9 and 1.70 × 10 −2 M, at pH 5, and a lower detection limit of 1.11 × 10 −9 M. Validation of the assay method revealed excellent performance characteristics for Hg 2+ ions over a wide variety of other metal ions, including good selectivity, long-term response stability and high reproducibility. Applications, for the direct determination of mercury(II) in real samples, gave the results with good correlation with the data obtained by using cold vapor atomic absorption spectrometry.

Highly selective sensing of mercury (II) by development and characterization of a PVC-based optical sensor

A novel optical sensor that is highly selective to Hg 2+ ions is described. This is based on the use of 4-phenyl-2,6-bis(2,3,5,6-tetrahydrobenzo[b][1,4,7]trioxononin-9-yl)pyrylium perchlorate as an ionic carrier in a plasticized poly(vinyl chloride) membrane. The sensing membrane is capable of determining mercury(II) with a high selectivity over a wide dynamic range between 2.95 × 10 −10 and 3.20 × 10 −3 M at pH 5.0 with a lower detection limit of 1.01 × 10 −10 M. Validation of the assay method reveals excellent performance characteristics, including long life span, good selectivity for Hg 2+ ions over a wide variety of other metal ions, long-term response stability, and high reproducibility. Applications for direct determination of mercury in samples including dental amalgam, shaft water, and fountain give results with good correlation with data obtained using cold vapor atomic absorption spectrometry.

Synthesis and Reactions of 1‐(3‐Chloropropyl)‐6,7‐dimethoxy‐3‐methylbenzo[c]pyrylium Perchlorate.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Unusual Double ‘O/N to N/O’ Recyclization of 5-Alkyl-7,8-dimethoxy-2-arylbenzo[d]pyrrolo[3,2-b]pyrylium Perchlorates into 5-Alkyl-7,8-dimethoxy-2-arylfuro[2,3-c]isoquinolines

Novel unusual double recyclization of both pyrrole and pyrylium cores of 5-alkyl-7,8-dimethoxy-2-phenylbenzo[d]pyrrolo[3,2-b]pyrylium perchlorate by nucleophiles is described, which regardless of the nucleophile (ammoniumcarbamate, triethylamine, sodium acetate, HCI in methanol), results in 5-alkyl-7,8-dimethoxy-2-phenylfuro[2,3-c]isoquinoline. The structure of 5-methyl-7,8-dimethoxy-2-phenylfuro[2,3-c]isoquinoline was established from X-ray diffraction analysis.

Determination of Salbutamol, Amikacin and Paromomycin Sulfate by a Novel Sulfate Polymeric Membrane Sensor Based on 2,6-diphenyl 4-(4-methoxyphenyl) pyrylium perchlorate

A novel sulfate polymeric membrane sensor based on 2,6-diphenyl 4-(4-methoxyphenyl) pyrylium perchlorate (DMPP) as a sensing material is presented. The electrode displays a very low detection limit (4.0×10−7 M) and wide working concentration range (8.0×10−7–1.0×10−1 M). The sensor shows remarkable selectivity toward sulfate over most common organic and inorganic anions, including chloride, acetate, nitrate, nitrite, bromide, iodide, thiocyanate, phosphate, fluoride, sulfite, hydrogen sulfite, hydrogen carbonate, citrate, tartarate and oxalate. The sensor reveals a Nernstian behavior (slope of −29.7±0.5 mV per decade) in a wide pH range (3.0–9.5). The proposed sensor shows a short response time over the entire working range (∼15 s) and was successfully applied to the direct determination of salbutamol, amikacin and paromomycin sulfate.

Synthesis and Reactions of 1-(3-Chloropropyl)-6,7-dimethoxy-3-methylbenzo[c]pyrylium Perchlorate

Acid-catalyzed acylation of 3,4-dimethoxyphenylacetone with γ-chlorobutyryl chloride gave 1-(3-chloropropyl)-6,7-dimethoxy-3-methylbenzo[c]pyrylium perchlorate. Recyclization of the product with nitrogen nucleophiles (ammonia, primary amines, hydrazine derivatives, hydroxylamine) led through the corresponding isoquinolinium salts to benzo[f]indolizinium, pyridazino[2,1-b]isoquinolinium, and 1,2-oxazino[2,1-b]isoquinolinium salts.

Reactions of 4-Methoxy-2-(4-methoxyphenyl)-9-oxocyclo-hepta[b]pyrylium Perchlorate with Active Methylene Compounds

4-Methoxy-2-(4-methoxyphenyl)-9-oxocyclohepta[b]pyrylium perchlorate (1) reacted with active methylene compounds to give two types of products. The reactions with nitromethane and cyano-substituted active methylene compounds occurred at the 4-position to yield 4-methylene-substituted 4,9-dihydrocyclohepta[b]pyran-9-ones (2, 3a-d). On the other hand, the reactions with active methylene compounds having an acetyl group took place at the 9a-position to give the ring-opened 6,7-dimethylenecyclohepta-2,4-dien-1-ones (4a-d). In the reactions with malonic acid diesters, 2H-cyclohepta[b]furan-2-ones (5a,b) were obtained by the attack at the 9a-position, ring-opening, and recyclization. Compound (5a) reacted with in situ-generated enamines to afford azulene derivatives (6a-e).

One‐Step Synthesis of a Naphtho[1,2‐b]furan Derivative from Benzo[c]pyrylium Perchlorate.

AbstractFor Abstract see ChemInform Abstract in Full Text.

One-Step Synthesis of A Naphtho[1,2-b]furan Derivative from Benzo[c]pyrylium Perchlorate

One-Step Synthesis of A Naphtho[1,2-b]furan Derivative from Benzo[c]pyrylium Perchlorate

Free Radicals: XXVII. Synthesis of 2,6-Diphenyl-4-[p-(2,6-diphenyl-4-pyridyl)phenyl]pyranyl

Starting with 2,6-diphenyl-4-(p-tolyl)pyridine a synthesis of 2,6-diphenyl-4-[p-(2,6-diphenyl-4-pyridyl)phenyl]pyrylium perchlorate was performed. By reduction of the latter the corresponding radical was obtained. The radical was shown to be unstable with respect to oxygen.

Reactions of 3‐acetyltropolone with benzaldehydes in trimethyl orthoformate in the presence of perchloric acid: Synthesis of 2‐aryl‐4‐methoxy‐9‐oxocyclohepta[b]pyrylium perchlorates

Abstract3‐Acetyltropolone (1) reacted with benzaldehydes in trimethyl orthoformate in the presence of perchloric acid to afford 2‐aryl‐4‐methoxy‐9‐oxocyclohepta[b]pyrylium perchlorates 3a‐c in 25–37% yields. From the filtrates, 3‐(3,4‐diaryl‐3‐butenoyl)tropolones 4a,b and 3‐(2‐methoxycinnamoyl)tropolone (5) were also isolated.