Use of coumarin derivatives as activators in the peroxyoxalate system in organic and aqueous media

https://doi.org/10.1016/j.jphotochem.2020.113076Get rights and content

Highlights

  • Coumarins can be utilized as activators in the peroxyoxalate system in anhydrous and aqueous media.

  • Rate constants are independent of the nature and the concentration of the activator.

  • Coumarin activators do not participate in the rate-limiting step.

  • The highest quantum yields are obtained with coumarin 153 as activator.

  • Chemiexcitation mechanism operating with the coumarin activators is Chemically Initiated Electron Exchange Luminescene.

Abstract

The peroxyoxalate system – base catalyzed reaction of oxalic ester derivatives with hydrogen peroxide in the presence of a fluorescent activator – is one of the most efficient chemiluminescence transformations known and widely utilized in analytical and bioanalytical applications. Coumarin derivatives have found widespread application as fluorescent labels for the determination of enzymatic activity in biological fluids and in fluorescence immunoassays, among others. In this work, we show that coumarin derivatives can be utilized as activators in the peroxyoxalate reaction (with two oxalic esters, including a new, environmentally compatible derivative) in anhydrous and aqueous systems, leading to reproducible kinetic results and singlet quantum yields similar to that obtained with commonly utilized activators. Quantum yields are lower in aqueous than in anhydrous medium, however still considerably high to allow the application in analytical and bioanalytical assays. The chemiluminescence parameters (singlet quantum yields at infinite activator concentration and relative electron transfer rate constants) determined in the systems indicate the occurrence of electron or charge transfer steps according to the Chemically Initiated Electron Exchange Luminescence (CIEEL) mechanism.

Introduction

Coumarin derivatives are widely distributed in the plant kingdom, some of them show physiological activity, whereas many derivatives are of great interest for diverse practical applications. [[1], [2], [3], [4], [5], [6], [7]] Synthetic coumarin derivatives are widely utilized as laser dyes [[8], [9], [10]], optical brighteners [11], as well as fluorescence labels [[12], [13], [14], [15]]. Additionally, some coumarin derivatives show antimicrobial properties and others are employed as fluorescence probes for the determination of proteolytic enzyme activity in biological fluids [16], in fluorescence immunoassays [17,18], for intercellular cerebral pH measurements [19], as well as in the treatment of skin diseases [[19], [20], [21]].

On the other hand, chemiluminescence systems have been utilized in a great variety of analytical and bioanalytical assays. [[22], [23], [24], [25], [26], [27], [28], [29], [30]] The general mechanisms of organic chemiluminescence involve the unimolecular decomposition of cyclic peroxides (1,2-dioxetanes or 1,2-dioxetanones) with the preferential generation of triplet-excited states [[31], [32], [33]] and a catalytic process, where peroxide decomposition is initiated by and electron or charge transfer from an appropriate catalyst, called activator (ACT) [34]. The catalyzed decomposition, denominated Chemically Initiated Electron Exchange luminescence (CIEEL,) can lead to the preferential formation of emissive singlet excited states, however, the efficiency of the intermolecular process is generally low, eventually due to sterical hindrance. [[35], [36], [37]] Contrarily, when the CIEEL process is of intramolecular nature, the efficiency is very high, being able to reach quantum yields of up to 1.0 E/mol [[38], [39], [40], [41]]. The most efficient intramolecular CIEEL system is the induced decomposition of 1,2-dioxetane derivatives containing a protected phenoxyl moiety as substituent, generating, upon deprotection with a chemical reagent or enzymatically, phenolate as an excellent internal electron donor [[42], [43], [44]]. This kind of 1,2-dioxetanes is the basis for a wide variety of chemiluminescent immunoassay and several other bioassays related to the determination of enzyme activities [[45], [46], [47], [48], [49]].

As outlined above, the singlet quantum yields and thereby chemiluminescence emission quantum yields in intermolecular CIEEL systems are generally low (in the order of 10−4 E/mol). [35,38] Contrarily, the peroxyoxalate reaction possesses very high efficiency [[50], [51], [52]], moreover the occurrence of an electron or charge transfer in its chemiexcitation step between a high-energy intermediate (HEI) formed and an activator (ACT) has been unequivocally shown [[52], [53], [54], [55]]. This highly efficient chemiluminescence reaction, with widespread analytic and practical applications [22,30,56,57], consists in the base-catalyzed reaction of activated oxalic acid derivatives with hydrogen peroxide in the presence of a highly fluorescent chemiluminescence ACT with low oxidation potential, leading to the formation of carbon dioxide and light emission form the ACT [50,58]. The reaction proceeds by base catalyzed hydrogen peroxide attack to the oxalate derivative with formation of a monoperoxalate derivative, [[59], [60], [61], [62]] which, upon cyclization, leads to the formation of a cyclic four-membered peroxide, most likely 1,2-dioxetanedione (Scheme 1). [55,[62], [63], [64]] The interaction of this HEI with the ACT, initiated by a charge or electron transfer from the ACT to the HEI, leads to peroxide cleavage and the ACT’s excited singlet state formation, resulting in chemiluminescence by fluorescence emission from the ACT (Scheme 1). [52,53] The use of ACTs with different fluorescence emission wavelengths leads to differently colored chemiluminescence emission [[65], [66], [67], [68], [69]].

Due to the facts that coumarin derivatives are widely utilized in bioassays in vitro and in vivo, as well as the peroxyoxalate reaction being highly efficient and adequate for the utilization in chemiluminescence assay, the peroxyoxalate chemiluminescence is studied here with three different representative coumarin derivatives as activators (COU120, COU151 and COU153), using the commercially available and widely utilized bis(2,4,6-trichlorophenyl) oxalate (TCPO), as well as the new, non-toxic bis(3-(methoxycarbonyl)phenyl) oxalate (MCPO) derivative, in anhydrous as well as aqueous media.

Section snippets

Experimental section

Bis(2,4,6-trichlorophenyl) oxalate (TCPO) (Sigma ≥ 99 %) was recrystallized from a chloroform/n-hexane mixture (14:5) (mp 189 - 191 °C, lit. 190 °C). [70] Imidazole (IMI-H, Sigma, 99 %), coumarins 153, 151 and 120 (all Aldrich) were used without further purification.

Bis(3-(methoxycarbonyl)phenyl) oxalate (MCPO) was synthesized from the reaction between methyl 3-hydroxybenzoate and oxalyl chloride following the procedure previously reported for methyl salicylate as phenol derivative. [71] Methyl

Results and discussion

The imidazole catalyzed reactions of the oxalates TCPO and MCPO with hydrogen peroxide in DME and DME / water in the presence of the three activators COU121, COU151 and COU153 were studied in standard conditions ([TCPO] =0.10 mmol L−1 or [MCPO] =0.10 mmol L−1; [IMI-H] =2.0 mmol L−1, 5.0 mmol L−1 or 10 mmol L−1; [H2O2] = 10 mmol L−1), leading to kinetic emission curves easily observed in a conventional fluorimeter. The reactions are considerably faster in the aqueous medium as compared to pure

Conclusions

Coumarins, like the derivatives COU120, COU151 and COU153 can be utilized as activators in peroxyoxalate chemiluminescence in anhydrous and aqueous media, leading to reproducible results. Singlet quantum yields are similar to that obtained with the commonly utilized polycondensed aromatic hydrocarbon activators. The environmentally compatible oxalic ester bis(3-(methoxycarbonyl)phenyl) oxalate (MCPO) leads to slightly lower quantum yields than the commonly utilized polychlorinated derivative

CRediT authorship contribution statement

Maidileyvis C. Cabello: Investigation, Writing - original draft, Formal analysis, Visualization. Liena V. Bello: Investigation, Formal analysis, Visualization. Wilhelm J. Baader: Conceptualization, Writing - original draft, Writing - review & editing, Project administration, Funding acquisition.

Declaration of Competing Interest

The authors report no declarations of interest.

Acknowledgements

The authors would like to thank Solvay Peróxidos do Brasil for a generous donation of hydrogen peroxide. The authors also would like to thank funding by Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Brazil (MCC (147138/2016-7), LVB (141816/2017-1)) for financial support in the form of PhD fellowships and Coordenadoria de Aperfeioamneto de Pessoal de Ensino Superior (CAPES), Brazil, for support to the Graduate Progaram of Chemistry, IQUSP. Furthermore, the generous

References (79)

  • S. Sadeghi Mohammadi et al.

    Chemiluminescent liposomes as a theranostic carrier for detection of tumor cells under oxidative stress

    Anal. Chim. Acta

    (2019)
  • S. Gnaim et al.

    Light emission enhancement by supramolecular complexation of chemiluminescence probes designed for bioimaging

    Chem. Sci.

    (2019)
  • F.H. Bartoloni et al.

    Chemiluminescence efficiency of catalyzed 1,2-dioxetanone decomposition determined by steric effects

    J. Org. Chem.

    (2015)
  • A.L.P. Nery et al.

    Fluoride-triggered decomposition of m-sililoxyphenyl-substituted dioxetanes by an intramolecular electron transfer (CIEEL) mechanism

    Tetrahedron Lett.

    (1999)
  • A.L.P. Nery et al.

    Studies on the intramolecular Electron transfer catalyzed thermolysis of 1,2-dioxetanes

    Tetrahedron

    (2000)
  • A.P. Schaap et al.

    Chemical and enzymatic triggering of 1,2-dioxetanes. 3: alkaline phosphatase-catalyzed chemiluminescence from an aryl phosphate-substituted dioxetane

    Tetrahedron Lett.

    (1987)
  • A.P. Schaap et al.

    Chemical and enzymatic triggering of 1,2-dioxetanes. 1: aryl esterase-catalyzed chemiluminescence from a naphthyl acetate-substituted dioxetane

    Tetrahedron Lett.

    (1987)
  • A.P. Schaap et al.

    Chemical and enzymatic triggering of 1,2-dioxetanes. 2: fluoride-induced chemiluminescence from tert-butyldimethylsilyloxy-substituted dioxetanes

    Tetrahedron Lett.

    (1987)
  • L.J. Kricka

    Clinical applications of chemiluminescence

    Anal. Chim. Acta

    (2003)
  • R. Liu et al.

    Magnetic-particle-based, ultrasensitive chemiluminescence enzyme immunoassay for free prostate-specific antigen

    Anal. Chim. Acta

    (2013)
  • E.A.A. Chandross

    New chemiluminescent system

    Tetrahedron Lett.

    (1963)
  • R. Bos et al.

    Studies on the mechanism of the peroxyoxalate chemiluminescence reaction: part 1. Confirmation of 1,2-dioxetanedione as an intermediate using13C nuclear magnetic resonance spectroscopy

    Anal. Chim. Acta

    (2004)
  • S.A. Tonkin et al.

    Studies on the mechanism of the peroxyoxalate chemiluminescence reaction. Part 2. Further identification of intermediates using 2D EXSY13C nuclear magnetic resonance spectroscopy

    Anal. Chim. Acta

    (2008)
  • M. Shamsipur et al.

    A study of chemiluminescence from reaction ofbis(2,4,6-trichlorophenyl)oxalate, hydrogen peroxide and an opticalbrightener 5-(3-anilino-5-chloroanilino)-2-{(E)-2-[4-(3-anilino-5-chloroanilino)-2-sulfophenyl]-1-ethenyl}-1-benzenesulfonic acid

    Dyes Pigm.

    (2007)
  • A. Yari et al.

    Chemiluminescence of curcumin and quenching effect of dimethyl sulfoxide on its peroxyoxalate system

    J. Lumin.

    (2010)
  • Y. Qiu et al.

    A further study on the degradation mechanism of rhodamine 6G in the peroxyoxalate chemiluminescent reaction

    J. Photochem. Photobiol. A: Chem.

    (1995)
  • S.Y. Kazemi et al.

    A study of chemiluminescence characteristics of a novel peroxyoxalate system using berberine as the fluorophore

    Dyes Pigm.

    (2012)
  • G.B. Schuster et al.

    Chemiluminescence of organic compounds

    Adv. Phys. Org. Chem.

    (1982)
  • X.Y. Sun et al.

    Synthesis and application of coumarin fluorescence probes

    RSC Adv.

    (2020)
  • M.L. Odyniec et al.

    Peroxynitrite activated drug conjugate systems based on a coumarin scaffold toward the application of theranostics

    Front. Chem.

    (2019)
  • A. Gualandi et al.

    Application of coumarin dyes for organic photoredox catalysis

    Chem. Commun.

    (2018)
  • A.M. Saleh et al.

    The effect of coumarin application on early growth and some physiological parameters in Faba bean (Vicia faba L.)

    J. Plant Growth Regul.

    (2015)
  • D. Cao et al.

    Coumarin-based small-molecule fluorescent chemosensors

    Chem. Rev.

    (2019)
  • V.R. Mishra et al.

    Photostability of coumarin laser dyes - a mechanistic study using global and local reactivity descriptors

    J. Fluoresc.

    (2017)
  • X. Liu et al.

    Molecular origins of optoelectronic properties in coumarin dyes: toward designer solar cell and laser applications

    J. Phys. Chem. A

    (2012)
  • S. Pajk et al.

    Fluorescent membrane probes based on a coumarin-thiazole scaffold

    Acta Chim. Slov.

    (2019)
  • G. Liu et al.

    Synthesis and application of polymeric fluorescent compounds based on coumarin

    Adv. Sci. J.

    (2015)
  • R.J. Ambrose

    Organic luminescent materials

    J. Polym Sci. Part C: Polym. Lett.

    (1989)
  • S.G. Thompson et al.

    Substrate-labeled fluorescent immunoassay for amikacin in human serum

    Antimicrob. Agents Chemother.

    (1980)
  • Cited by (3)

    View full text