The chemiluminescent peroxyoxalate system: state of the art almost 50 years from its discovery

Abstract

Almost fifty years after the discovery of the peroxyoxalate reaction by E. A. Chandross in the early nineteen sixties, this review article intends to give a general overview on mechanistic aspects of this system and to describe the principles of its analytical application. After a short general introduction on the principles of chemiluminescence and the history of peroxyoxalate discovery, mechanistic aspects of high-energy intermediate formation, its structure and its reaction with an activator in the peroxyoxalate system are discussed. Finally, analytical applications of peroxyoxalate chemiluminescence are exemplified using representative recent examples, including oxalic acid detection in biological samples.

Mechanistic Study of the Peroxyoxalate System in Completely Aqueous Carbonate Buffer

“…5), indicating that the activator does not participate in the rate‐limiting step and that the chemiexcitation process is faster than the initial steps of the peroxyoxalate reaction. This is in agreement with results obtained before for the reaction in anhydrous conditions (4,5,15–17). The singlet quantum yield at infinite activator concentration of Ф S ∞ = (5.8 ± 0.2) × 10 –7 E mol –1 is significantly lower than yields commonly determined in anhydrous media (3,16,17,32) however, comparable to quantum yields observed in partially aqueous media (25,26,42).…”

“…Peroxyoxalate reaction occurring by formation of a high‐energy intermediate (HEI), light emission is achieved by its interaction with an activator (ACT) (4,5). …”

“…The peroxyoxalate system is a chemiluminescent (CL) reaction applied as an efficient and sensitive analytical tool (1)(2)(3)(4)(5). It is the base-catalyzed reaction of hydrogen peroxide with an aromatic oxalic ester, forming a high-energy intermediate (HEI) (Scheme 1) (4)(5)(6)(7)(8)(9)(10)(11)(12).…”

Oxidation of dimethylplatinum(II) complexes with malonyl peroxide derivatives

“…All of the reactions are favourable, as expected, with the OP reaction most exothermic due, at least in part, to relief of the high ring strain in the reagent OP. [37][38][39] It has been argued that the strain in the peroxide ring is slightly greater in CBMP than in CPMP, 46 and this may account for the small difference of 2 kcal mol −1 calculated for the energies of reaction with [PtMe 2 (bipy)] (Fig. 5).…”

“…These peroxides are expected to give six-membered chelates on oxidative addition to platinum(II). Unfortunately, oxalyl peroxide, OP, (Chart 1) is too strained to be isolated as a pure compound, although it is an important intermediate in chemiluminescence, [37][38][39] and so the formation of five-membered chelates could not be achieved directly. New insights into the mechanism of peroxide oxidative addition are presented.…”