Spectroscopic Studies on the Interaction of Metallic Ions with an Imidazolyl-Phenolic System

Orfão, Ronaldo Barros; Alves, Jessica; Bartoloni, Fernando Heering

doi:10.1007/s10895-016-1828-x

Cited by 9 publications

(29 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The triphenylimidazole structural framework has been intensely studied throughout the years, by many different research groups, due to its fluorescence (FL) and chemiluminescence (CL) properties. The typical direct CL of 2,4,5‐triphenylimidazole (also known as lophine) with oxygen in an alkaline media, first described by Radziszewski in 1877, was studied mainly to elucidate its reaction mechanism .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The decomposition of triphenylimidazole‐para‐acetate follows specific base catalysis and can be conveniently followed by fluorescence

et al. 2019

Self Cite

View full text Add to dashboard Cite

The kinetics of the decomposition reaction of 4-(4,5-diphenyl-1H-imidazol-2-yl)phenyl acetate (1) in basic alcoholic media was investigated, using a simple fluorescence (FL) spectrophotometric procedure. The process was conveniently studied using FL, since the triphenylimidazole-derived ester 1 and its reaction products (the corresponding phenol 2 and phenolate 2 − ) are all highly fluorescent (Φ FL > 37%). By carefully selecting excitation and emission wavelengths, observed rate constants k 1 in the order of 10 −3 to 10 −2 s −1 were obtained from either reactant consumption (λ ex = 300 nm, λ em = 400 nm) or product formation (λ ex = 350 nm, λ em = 475 nm); these were shown to be kinetically equivalent. Intensity-decay time profiles also gave a residual FL intensity parameter, shown to be associated to the distribution of produced species 2 and 2 − , according to the basicity of the medium. Studying the reaction in both methanol (MeOH) and isopropanol (iPrOH), upon addition of HO − , provided evidence that the solvent's conjugate base is the active nucleophilic species.When different bases were used (tBuO − , HO − , DBU and TEA), bimolecular rate constants k bim ranging from 4.5 to 6.5 L mol −1 s −1 were obtained, which proved to be non-dependent on the base pK aH , suggesting specific base catalysis for the decomposition of 1 in alcoholic media. KEYWORDS imidazole, kineticslight emissionlophine, rate constant 1 | INTRODUCTIONThe triphenylimidazole structural framework has been intensely studied throughout the years, by many different research groups, due to its fluorescence (FL) [1][2][3][4][5][6][7][8][9] and chemiluminescence (CL) [10][11][12][13][14][15][16][17][18][19][20][21][22] properties. The typical direct CL of 2,4,5-triphenylimidazole (also known as lophine) with oxygen in an alkaline media, first described by Radziszewski in 1877, [23] was studied mainly to elucidate its reaction mechanism. [11][12][13][18][19][20][21][22]24] However, lophine and its derivatives were also applied in other CL systems, being used as activators of the peroxyoxalate reaction [10] or enhancers of the luminol transformation. [25][26][27] In part, the vast array of application of these molecules, from FL to CL measurements, depends on the high FL quantum yields (Φ FL > 0.1) presented by them. [1][2][3][4][5][6][7][8][9][10]17,[24][25][26][27] In 1993, Kuroda et al. reported that triphenylimidazole-para-acetate (1, IUPAC name 4-(4,5-diphenyl-1H-imidazol-2-yl)phenyl acetate), as well as another three ester analogs based on pertinent fatty acids, could be applied on the evaluation of lipase activity through FL measurements. [8] Although ester 1 itself was not the most suitable for interaction with the lipase, it was primarily used to define the methodology for activity determination. Briefly, the method consisted on hydrolyzing the ester with the enzyme, followed by separation and FL

show abstract

Section: Introductionmentioning

confidence: 99%

“…However, lophine and its derivatives were also applied in other CL systems, being used as activators of the peroxyoxalate reaction or enhancers of the luminol transformation . In part, the vast array of application of these molecules, from FL to CL measurements, depends on the high FL quantum yields ( Φ FL > 0.1) presented by them …”

Section: Introductionmentioning

confidence: 99%

The decomposition of triphenylimidazole‐para‐acetate follows specific base catalysis and can be conveniently followed by fluorescence

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…8 In the opposite way, switching off mechanism is the quenching effect of the emission intensity with increasing concentration of metal ions. 3 In recent years, [9][10][11][12][13] several chemosensors were reported to operate based on an excited state intramolecular proton transfer (ESIPT, Scheme 1) process. The ESIPT process can be interpreted as the disturbance of the equilibrium between two tautomers, the enolic (E) and ketonic (K) species, that happens after absorption of a photon.…”

Section: Introductionmentioning

confidence: 99%

“…Such phenomenon occurs with an imidazolyl-phenolic framework, 7 as the one present in 2-(4,5-diphenyl-1H-imidazol-2-yl)phenol (1) 14 and its derivative 2,4-di-tert-butyl-6-(4,5-diphenyl-1Himidazol-2-yl)phenol (2). 13 The phototautomerization reaction occurs once that the E 0 tautomer is the most stable on the fundamental state (when compared to K 0 ) and, after the formation of the excited state E 1 , the ESIPT process generates the more stable electronically excited tautomer K 1 . After deactivation of the K 1 state through the emission of a photon, the system thermally equilibrates from K 0 back to the more stable E 0 species.…”

Section: Introductionmentioning

confidence: 99%

“…15 The presence of certain metallic ions induces the formation of a complex, which prevents the formation of the ketonic species and, thus, the ESIPT process is inhibited, changing the emission profile of the probe (Scheme 1). 7,13 Our research group recently reported the application of compound 2 as a fluorescent sensor to detect Al 3+ , Cr 3+ , Fe 3+ and Cu 2+ ions, 13 which occurs due to the formation of a complex and inhibition of the ESIPT process, thus, quenching the ketonic species emission. Moreover, the interaction between 2 and the aforementioned trivalent cations results on a new emission band, attributed to the fluorescence of a locked-enol tautomer, stabilized due to coordination.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On the Fluorescent, Steric and Electronic Factors Affecting the Detection of Metallic Ions Using an Imidazolyl-Phenolic Derived Fluorescent Probe

Orfão¹,

Carvalho²,

Homem-de-Mello³

et al. 2017

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

The imidazolyl-phenolic probe used at the present study has its photophysic properties regulated by a tautomeric equilibrium. After the absorption of a photon, an excited state intramolecular proton transfer process generates a ketonic species, responsible for the 440 nm emission (in CH 3 CN/H 2 O, 95:5, v/v). Addition of Cu 2+ , Al 3+ , Cr 3+ and Fe 3+ suppresses emission through a combination of dynamic and static-like quenching, as indicated by Stern-Volmer plots, with a higher sensitivity for Cu 2+ (K SV = 1.90 × 10 5 and 2.40 × 10 4 L mol-1 , respectively, for Cu 2+ and Fe 3+). The trivalent ions led to the formation of a locked-enol tautomer that emits at shorter wavelengths; this coordinated compound is also quenched at metallic ions concentrations above 20 μmol L-1 , due to a collisional process. When compared to another imidazolyl-phenolic probe, experimental and simulated data revealed that fluorescent, steric and electronic effects regulate their sensitivity towards the ions.

show abstract

Barbituric acid appended fluorescent sensor for the detection of Cu2+/Hg2+ ions along with real-life utility in recognition of malathionin food samples and fingerprint imaging

Jindal

Kaur

2023

Journal of Photochemistry and Photobiology A: Chemistry

View full text Add to dashboard Cite

Spectroscopic Studies on the Interaction of Metallic Ions with an Imidazolyl-Phenolic System

Cited by 9 publications

References 39 publications

The decomposition of triphenylimidazole‐para‐acetate follows specific base catalysis and can be conveniently followed by fluorescence

The decomposition of triphenylimidazole‐para‐acetate follows specific base catalysis and can be conveniently followed by fluorescence

On the Fluorescent, Steric and Electronic Factors Affecting the Detection of Metallic Ions Using an Imidazolyl-Phenolic Derived Fluorescent Probe

Barbituric acid appended fluorescent sensor for the detection of Cu2+/Hg2+ ions along with real-life utility in recognition of malathionin food samples and fingerprint imaging

Contact Info

Product

Resources

About