Chemiluminescence Properties Research Articles

Effect of surfactants on the spectrofluorimetric properties of zearalenone

The chemiluminescent properties of the estrogenic mycotoxin zearalenone in the presence of aqueous micellar media were investigated using steady state fluorescence techniques. Micelles of surfactants sodium dodecyl sulfate (SDS), hexadecyltrimethylammonium bromide (CTAB), and non-ionic Triton X-100 enhanced the fluorescence intensity of zearalenone in aqueous solutions. The binding constants have been determined and indicate zearalenone has the highest affinity for Triton X-100, followed by CTAB, and then by SDS. The encapsulation of zearalenone by the micelles studied is spontaneous and exothermic. The selective microenvironments provided by organized micellar systems offer an attractive medium to modulate fluorescence detection of zearalenone.

Directly Oxidized Chemiluminescence of 2-Substituted-4,5-di(2-Furyl)-1H -Imidazole by Acidic Potassium Permanganate and its Analytical Application for Determination of Albumin

In the paper, 2,4,5-tri(2-furyl)-1H-imidazole (TFI) and 2-phenyl-4,5-di(2-furyl)-1H-imidazole (PDFI), were chosen to investigate chemiluminescence (CL) properties of 2-substituted-4,5-di(2-furyl)-1H-imidazoles. The directly oxidized CL of analytes by potassium permanganate (KMnO(4)) was in detail studied. The KMnO(4) could directly oxidize TFI/PDFI to produce strong CL emission in acidic solution. The effects of experimental conditions were investigated. Under the optimal conditions, the effect of albumin on the TFI/PDFI-KMnO(4) system was investigated. It was found that the addition of albumin into the system could induce enhancement of CL signal, and the enhanced CL intensity is linearly related to the logarithm of concentration of albumin. Based on this study, a novel CL method has been developed for the determination of albumin with high sensitivity and good selectivity. The method was applied to the determination of albumin in human serum samples, and the results were in agreement with those obtained by the bromcresol green (BCG) method. The relative errors for the analytical results were from -5.8% to 4.2%. These new phenomena would further enable people to exploit more CL analytical application of the heterocyclic imidazole derivatives.

Synthesis, characterization and photophysical properties of organosoluble and thermally stable polyamides containing pendent N-carbazole group

A series of novel polyamides that carry carbazole-containing pendent was prepared by direct polycondensation of a diamine, N-(4-(carbazol-9-yl)phenyl)-3,5-diaminobenzamidamide (DAC), and various aliphatic and aromatic dicarboxylic acids. All the resulting polyamides were amorphous with inherent viscosities ranged from 0.51 to 0.65 dL/g and were readily soluble in many organic solvents which could be solution-cast into transparent and tough films. The glass transition temperatures ( T g ) of these polymers were affected considerably by their chemical structure and ranged from 195 to 300 °C. They had useful levels of thermal stability associated with relatively high temperatures of 10% weight loss ( T 10) in the range of 385–480 °C in nitrogen atmosphere. These polymers exhibited strong UV–vis absorption maxima in solution and in solid state, and their photo- and chemi-luminescence properties were studied. photoluminescence (PL) efficiency of the polyamides were affected by their chemical structure (PL quantum yield up to 32%). The aliphatic polyamides emitted blue light ( λ e.max = 435–450 nm), while the aromatic polyamides emitted green light ( λ e.max = 485–492 nm) both in solution and solid state.

A novel and unusually long-lived chemiluminophore based on the 7-hydroxycoumarin scaffold

Synthesis and chemiluminescent properties of a new 1,2-dioxetane chemiluminophore bearing a 7-hydroxycoumarin moiety are presented. The 1,2-dioxetane decomposition ended up with strong and long-lived emission of light. This new structure opens way to the development of a new generation of bright chemiluminescent bio-probes.

Sonochemical selective synthesis of ZnO/CdS core/shell nanostructures and their optical properties

The core/shell-type ZnO nanosphere/CdS nanorod and ZnO nanosphere/CdS nanoparticle composites have been selectively prepared through a simple ultrasound-assisted solution phase conversion process using monodispersed ZnO nanospheres as a starting reactant and in situ template. The formation mechanism of the products is closely connected with the sonochemical effect of ultrasonic irradiation. The photoluminescence and electrogenerated chemiluminescence properties of the as-prepared core/shell structures were investigated.

Influence of Electron-Donating and Electron-Withdrawing Substituents on the Chemiluminescence Behavior of Coelenterazine Analogs

Abstract Coelenterazine analogs 3a–3e possessing various substituents at the para-position of the 6-phenyl group (R = CF3, F, H, OMe, and NMe2) were synthesized, and the chemiluminescent properties of 3a–3e in dimethyl sulfoxide (DMSO) were investigated quantitatively. Chemiluminescence maxima observed in the range of 454–478 nm showed a bathochromic shift as the electron-donating ability of R increased. Chemiluminescence quantum yields (ΦCL) were obtained in the range of 0.0006–0.0018. The analog 3a possessing the electron-withdrawing CF3 group showed a slight decrease in its ΦCL value. The fluorescence quantum yields (ΦF) of the light emitter, 2-acetamidopyrazine anions 4a−–4e−, were observed in the range of 0.005–0.21 and showed substituent dependency in that the increment in the electron-withdrawing ability of R decreases the ΦF value. The efficiency of generation of the singlet-excited 4a−–4e− (ΦS) showed a small change in the range of 0.008–0.015. From these quantitative analyses of the quantum efficiencies, we found that an electron-donating substituent R is not required for the efficient generation of a singlet-excited light emitter, but is required for the high ΦF of the emitter.

ChemInform Abstract: Preparation of 2,4,5‐Triarylimidazol‐4‐ols and Their Stereoselective Rearrangement by 1,5‐Phenyl Migration.

AbstractLophine hydroperoxides (I) undergo base‐triggered phenyl migration to provide the imidazolones (III) instead of amidines with chemiluminescence properties.

Dependence of Electrochemical and Electrogenerated Chemiluminescence Properties on the Structure of BODIPY Dyes. Unusually Large Separation between Sequential Electron Transfers

Electrochemistry and electrogenerated chemiluminescence (ECL) of selected substituted BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) dyes have been studied. The location and nature of substituents on positions 1-8 are important in predicting the behavior, and especially the stability, of the radical ions formed on electron transfer. Dyes with unsubstituted positions 2, 6, and 8 show a kinetic contribution to both oxidation and reduction. Dyes with only unsubstituted positions 2 and 6 and a substituted 8 position show chemically reversible reduction but irreversible oxidation. Unsubstituted positions 2 and 6 tend to show dimer formation on oxidation. Completely substituted dyes show nernstian oxidation and reduction. Oxidation and reduction studies of simple BODIPY dyes show an unusually large separation between the first and second reduction peaks and also the first and second oxidation peaks, of about 1.1 V, which is very different from that observed for polycyclic hydrocarbons and other heteroaromatic compounds, where the spacing is usually about 0.5 V. Electronic structure calculations confirmed this behavior, and this effect is attributed to a greater electronic energy required to withdraw or add a second electron and a lower relative solvation energy for the dianion or dication compared with those of the polycyclic hydrocarbons. ECL was generated for all compounds either by annihilation or by using a co-reactant.

Utilizing the chemiluminescence of 2-substituted-4,5-di(2-furyl)-1H-imidazole–H2O2–Cu2+ system for the determination of Cu2+

In the paper, 2,4,5-tri(2-furyl)-1H-imidazole (TFI) and 2-phenyl-4,5-di(2-furyl)-1H-imidazole (PDFI), were chosen to investigate chemiluminescence (CL) properties of 2-substituted-4,5-di(2-furyl)-1H-imidazoles. The directly oxidized CL of analytes by H2O2 was in detail studied. The H2O2 could directly oxidize TFI/PDFI to produce strong CL emission in basic solution. The addition of Cu2+ into the system could induce significant enhancement of CL signal. Based on this study, it was found that the TFI/PDFI–H2O2–Cu2+ CL system could be successfully applied to the determination of Cu2+. The proposed method has been used to determine trace amount of Cu2+ with a limit of detection (3σ) of 6.5×10−11mol/L, which enables minimal amount of sample for analysis. A satisfactory result has been obtained for the determination of Cu2+ in the reference material samples. The possible oxidized CL mechanism was also discussed briefly based on the photoluminescence (PL) and CL spectra.

Effect of Anionic Surfactants with Different Structure on the Fluorescent Properties of the CPPO-H<sub>2</sub>O<sub>2</sub>-Rhodamine B System

The effect of anionic surfactants on the chemiluminescence (CL) properties of CPPO- H2O2-Rhodamine B system was researched, and the maximum fluorescent intensity of every system was found at the critical micelle concentration (CMC) of corresponding surfactant. The reduced vibration of Rhodamine B molecules induced by the combination of micelle was offered to explain the positive effect of anionic surfactants. Moreover, the structure of anionic surfactant was found to be relative to the enhanced fluorescent intensity, and the hydrophobic group’s structure and stereospecific blockade were considered as two main factors to the sensitization ability of anionic surfactant on CL.

ChemInform Abstract: Chemiluminescent Products of Reaction Between α-Keto Acids and 4, 5-Diaminophthalhydrazide.

The chemiluminescent products formed from α-keto acids and 4, 5-diaminophthalhydrazide dihydrochloride were characterized as corresponding 3-substituted-7, 8-dihydropyridazino[4, 5-g]quinoxaline-2, 6, 9(1H)-trione. The chemiluminescence properties of the products are described.

ChemInform Abstract: Synthesis and Absorption/Emission Spectroscopic Properties of Bis( phenylethynyl)benzenes and 9,10-Bis(phenylethynyl)anthracenes.

A series of bis(phenylethynyl)benzenes 3 and 9,10-bis(phenylethynyl)anthracenes 4 was synthesized by bromination–dehydrobromination reaction or newly developed direct CC triple bond formation reaction from styrylstilbenes 1 or distyrylanthracenes 2. Subsequently systematic investigations were carried out on their absorption and fluorescence spectra, and their chemiluminescence properties. The following points are apparent; (a) a linear relationship between ν and Hammett's σp of compounds 3 and 4 was observed, (b) a significant relationship between the Stokes' shift of 4 and σp was observed and (c) in the series of compounds 4 the electron-donating ability of the substituents has a pronounced effect on the chemiluminescence properties.

ChemInform Abstract: Synthesis and Chemiluminescence Properties of 6-(4-Methoxyphenyl)-2- methylimidazo(1,2-a)pyrazin-3(7H)-one and 2-Methyl-6-(2-naphthyl)- imidazo(1,2-a)pyrazin-3(7H)-one.

New Cypridina luciferin analogues, 6-(4-methoxyphenyl)-2-methylimidazo[1,2-a]pyrazin-3(7H)-one (MCLA) and 2-methyl-6-(2-naphthyl)imidazo[1,2-a]pyrazin-3(7H)-one (NCLA), were prepared together with their oxyluciferin analogues, 2-acetamido-5-(4-methoxyphenyl)pyrazine (MCOLA) and 2-acetamido-5-(2-naphthyl)pyrazine (NCOLA). Various chemiluminescence properties of these compounds were compared with those of known luciferin analogues, 2-methyl-6-phenylimidazo[1,2-a]pyrazin-3(7H)-one (CLA) and 6-(3-indolyl)-2-methylimidazo[1,2-a]pyrazin-3(7H)-one (ICLA). The light yields obtained from ICLA, MCLA, and NCLA were much higher than CLA in diethylene glycol dimethyl ether (diglyme), in which triplet oxygen was the oxidant. In aqueous solution, employing superoxide ion as the oxidant, NCLA emitted light weaker than CLA and MCLA. ICLA gave almost no light on account of no fluorescence intensity of the emitter (oxyluciferin analogue ICOLA) in aqueous solution. For applications to the detection of active oxygen species p...

ChemInform Abstract: Indole Dioxetanes and Epoxides by Oxidation of N-Acylated Indoles with Singlet Oxygen and Dimethyldioxirane: Kinetics and Chemiluminescence Yields of the Thermal Dioxetane Decomposition and Fluoride Ion-Induced CIEEL Emission.

Photooxygenation of the N-acylated indoles 2 afforded the corresponding labile indole dioxetanes 3, the allylic hydroperoxides 4 and the carbamates 5. The dioxetanes were sufficiently stable for isolation and spectral characterization. Additionally, they were characterized by their chemiluminescence properties and chemical transformations, i.e. thermolysis to the fragmentation products 5 and dimethyl sulfide deoxygenation to the epoxides 7. The latter were independently prepared by dimethyldioxirane oxidation. The activation parameters (Ea, log A, ΔH‡, ΔS‡) and the excitation yields (ΦS, ΦT) of the direct chemiluminescence for the indole dioxetanes 3 were determined by standard isothermal kinetic methods. The fluoride ion-induced decomposition of the silyl-substituted dioxetane 3b released intramolecular CIEEL emission.

Synthesis and characterization of organo-soluble polyamides containing triaryl imidazole pendant and ether linkage moieties: thermal, photophysical, and chemiluminescent properties

A new symmetrical diamine monomer containing a triaryl imidazole pendant group was successfully synthesized by the nucleophilic substitution of hydroquinone with the synthesized 2-(2-chloro-5-nitrophenyl)-4, 5-diphenyl-1H-imidazole (I). A series of novel polyamides were prepared from the diamine monomer and various aliphatic and aromatic dicarboxylic acids via phosphorylation polyamidation. These polyamides are readily soluble in many organic solvents; their inherent viscosities ranged from 0.68 to 0.89 dl/g and gave tough and flexible films by solution-casting. They had useful levels of thermal stability associated with relatively high Tgs (186–278°C), 10% weight loss temperatures in the range of 355–482°C, and char yields at 600°C in air up to 67%. All the polyamides have fluorescence emission in dilute (0.2 g/dl) DMAc solution with maxima at 425–495 nm and with the quantum yields in the range 14–28%. The chemiluminescence activity of polyamides was also studied in the presence of peroxyoxalate. Copyright © 2010 John Wiley & Sons, Ltd.

Synthesis and identification of organosoluble polyimides: thermal, photophysical and chemiluminescence properties

Novel fluorescent polyimides (PIs) were prepared from a new diamine, 4-(4-(4-amino-2-(4,5-diphenyl-1H-imidazol-2-yl)phenoxy)phenoxy)-3-(4,5-diphenyl-1H-imidazol-2-yl)benzenamine, and three tetracarboxylic dianhydrides. The new symmetrical diamine was successfully synthesized by the nucleophilic substitution reaction of hydroquinone with 2-(2-chloro- 5-nitrophenyl)-4, 5-diphenyl-1H-imidazole (I). The PIs synthesized here are amorphous and soluble in polar aprotic solvents and demonstrate the ability to form films; their inherent viscosities ranged from 43 to 82 ml g−1. The PIs had suitable thermal stability and relatively high Tg values (245–274 °C), 10% weight loss temperatures in excess of 500 °C and char yields at 600 °C in air up to 62%. The PIs show emission in the solid state and in dilute (0.20 g per 100 ml) N,N-dimethyl acetamide solution at 431–464 nm with photoluminescence (PL) quantum yields in the range of 11–25%. The chemiluminescence activity of PIs in the presence of peroxyoxalate was also investigated. Novel fluorescent polyimides (PIs) were prepared from a new diamine, 4-(4-(4-amino-2-(4,5-diphenyl-1Hi-midazol-2-yl)phenoxy)phenoxy)-3-(4,5-diphenyl-1H-imidazol-2-yl)benzenamine(DA), and three tetracarboxylic dianhydrides. The PIs are amorphous and soluble in polar aprotic solvents and demonstrate a film-forming capability; their inherent viscosities ranged from 43 to 82 ml g−1. The PIs show emission in dilute (0.2 g per 100 ml) N,N-dimethyl acetamide solution with photoluminescence (PL) quantum yields in the range of 11–25%. The chemiluminescence (CL) activity of PIs in the presence of peroxyoxalate was also investigated.

Transferência de elétron inversa na quimiexcitação da reação peróxi-oxalato usando ativadores facilmente redutíveis Inverse electron transfer in peroxyoxalate chemiexcitation using easily reducible activators

Chemiluminescence properties of the peroxyoxalate reaction in the presence of activators bearing electron withdrawing substituents were studied, to evaluate the possible occurrence of an inverse electron transfer, from the peroxide intermediate to the activator, in its chemiexcitation step. Relative catalytic rate constants and singlet quantum yields were obtained for the peroxyoxalate reaction, using 9-chloro, 9,10-dichloro, 9-cyano and 9,10-dicyanoanthracenes as activators. The linear free-energy correlation of the relative rate constants with the activators' reduction potentials and the dependence of the quantum yields on the released energy confirm, for the first time, the occurrence of this inverse electron transfer.

Fluorescence and chemiluminescence properties of indolylmaleimides: experimental and theoretical studies

Various indolylmaleimides (IMs) were synthesized, and their fluorescence (FL) and chemiluminescence (CL) were measured. The substitution at the 2-position of the indole ring and the 3- or 4-position of the maleimide moiety caused an obvious change in the FL and CL of the IMs. An almost on-off switching of the FL of the IMs was observed. The intramolecular charge transfer from the indole moiety to the maleimide moiety occurred in 3-(1H-3-indolyl)-2,5-dihydro-1H-2,5-pyrroledione. In the FL of the IMs, CASPT2 calculations showed deprotonation of the NH group of the indole ring and the maleimide moiety at the excited state. The C[double bond, length as m-dash]C bond in the maleimide moiety was needed for strong CL in the IMs without substitution at the 2-position of the indole ring. The relationships between the FL or CL properties and the structures of the IMs were clarified. These results provide significant information on the rational design of IMs as FL and CL probes.

Green Electrogenerated Chemiluminescence of Highly Fluorescent Benzothiadiazole and Fluorene Derivatives

A group of highly fluorescent 2,1,3-benzothiadiazole derivatives (BH0-BH3), including two fluorene derivatives (AB2 and C01) were synthesized and characterized. The electrochemical, spectroscopic, and electrogenerated chemiluminescence (ECL) properties of the compounds were determined. Benzothiadiazole derivatives BH1, BH2, and BH3 show reversible oxidation and reduction waves and produce strong green ECL in nonaqueous solutions. This ECL could be seen by the naked eye, even in a well lit room. The fluorene derivatives, C01 and AB2, also produce bright, easily observable ECL. Since the ECL spectra are at essentially the same wavelengths as the photoluminescence (PL) spectra, and the energies of the electron transfer reactions are greater than the singlet state energies, we propose direct formation of the excited singlet state during ion annihilation. BH0, which shows a quasi-reversible oxidation wave, only produced weak ECL via direct annihilation but gave strong ECL with benzoyl peroxide (BPO) as a coreactant. The ECL quantum efficiencies of the series, compared to that of 9,10-diphenylanthrace, was estimated to range from 0.05 to 7%. This series shows rare green photoluminescence (lambda(PL) = 490-556 nm) with a high PL quantum efficiency in solution (Phi = 5 to 90%).

Synthesis and Spectroscopic Properties of Acridinium-9-sulfonamides

Abstract By introducing an electro-withdrawing antipyrine group, N -( p -toluenesulfonyl)- N -(4-antipyrine)-10-methylacridinium-9-carboxamide triflate is prepared. The UV, fluorescent (FL), and chemiluminescent (CL) properties of the target compound and of its precursor are investigated by comparing with those of the model compounds N -( p -toluenesulfonyl)- N -phenyl-10-methylacridinium-9-carboxamide triflate and the corresponding precursor, respectively. The results show that, compared with the corresponding model compound, acridine sulfonamide with a heterocyclic antipyrine group exhibits blue shift of both UV absorption and of maximum excitation wavelength ( λ ex ) and the emission wavelength ( λ em ) in FL spectra. The λ ex of the final target and its precursor are 268 and 274 nm, respectively, and the λ em are 321 and 327 nm, respectively, whereas the λ ex of the model compound and its unmethylated precursor are 365 and 359 nm, respectively, and the λ em are 504 and 440 nm, respectively. Moreover, the chemiluminescence of the final target compound triggered by H 2 O 2 could finish within 1.1 s, and the quantum yield is similar to that of the model compound, being 5.6 times high as that of luminol.