Spectroelectrochemical Study of N‐Substituted Phenoxazines as Electrochemical Labels of Biomolecules

Abstract

The electrochemical conversion of N-substituted phenoxazines (NSPs) bearing a CH 2 CH 2 ÀX substitute (where X¼OH, COOH, CH 2 NH 2 , CH 2 SO 3 H, CH 2 NHCOR) was investigated using cyclic voltammetry on a bulk gold electrode and a thin-layer spectroelectrochemical cell. The electrochemical oxidation of NSPs on the gold electrode was quasi-reversible and proceeded in a diffusion-controlled regime. The formal redox potential of NSPs covered the range from 0.39 to 0.45 V vs. SCE. The electrochemical oxidation of NSPs in the thin-layer spectroelectrochemical cell produced radical cations that showed absorbance at 385, 410 and 530 nm. Electrochemical conversion fitted the general voltammetric current-potential equation of a reversible wave, whereas electrolysis at constant potential showed a typical Cottrell behavior. Combining of NSPs with a biologically-relevant theophylline molecule did not change electrochemical and spectral properties of the phenoxazine core. Theophylline enlarged with NSPs demonstrated electrochemical and biocatalytic behavior similar to that of NSPs. The investigated NSPs possess electrochemical and spectral properties that are useful as biomolecular labels for electroanalysis.

Probing Reactivity of PQQ-Dependent Carbohydrate Dehydrogenases Using Artificial Electron Acceptor

“…3-(10H-Phenoxazin-10-yl)propionic acid (PPA), 3-(10H-phenoxazin-10-yl)-propane-1-sulfonic acid (PPSA), and 10-methyl-10H-phenoxazine (MPX) were synthesized as described in [15]. 1-(N,N-Dimethylamine)-4-(4-morpholine)benzene (AMB) was synthesized as described in [16].…”

Kinetics of N-substituted phenothiazines and N-substituted phenoxazines oxidation catalyzed by fungal laccases

“…3-(10H-phenoxazin-10-yl)-1-propanesufonic acid sodium salt (PPSA), 3-(10H-phenoxazin-10-yl)propanoic acid (PPA), 2-(10H-phenoxazin-10-yl)ethanol (PET) and 3-(10H-phenoxazin-10-yl)propylamine (PPAM) were synthesized as described in [12]. 3-(10H-phenothiazin-10-yl)-1-propanesulfonic acid sodium salt (PTPSA), 10-methyl-10H-phenothiazine-1-carboxylic acid (MPC1), 10-methyl-10H-phenothiazine-2-carboxylic acid (MPC2), 3-(10H-phenothiazin-10-yl)propan-1-ol (HPP) and 10-ethyl-10H-phenothiazine-4-carboxylic acid (EPC4) were obtained from Novozymes A/S (Copenhagen, Denmark).…”

“…The formal redox potential was calculated as the midpoint potential of the reduction and oxidation peaks potentials. The values of the redox potentials of the other investigated compounds were taken from references [8] and [12]. In [8] the redox potential values were measured at pH 7.0.…”

“…PTs are involved in laccase catalyzed recalcitrants conversion, dye oxidation and lignin degradation [4]. The oxidized forms of PXs show remarkable stability [11,12] therefore they may find new applications in laccase catalyzed processes.…”

Laccase Based Synergistic Electrocatalytical System

“…2-(10H-phenoxazin-10-yl)ethanol (PET), 3-(10H-phenoxazin-10-yl)propylamine (PPAM), the derivative of PPAM and theophylline-7-acetic acid, i.e. 2-(1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydro-7H-purin-7-yl)-N-[3-(10H-phenoxazin-10-yl)propyl] acetamide (PT) was synthesized as described in [14]. 10-methyl-10H-phenothiazine-1-carboxylic acid (MPC1), 10-methyl-10H-phenothiazine-2-carboxylic acid (MPC2) and 10-ethyl-10H-phenothiazine-4-carboxylic acid (EPC4) was obtained from Novozymes A/S (Copenhagen, Denmark).…”