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[Display omitted] • A 1,3/1,4-diazine's modified SPE for NB determination in honey was prepared. • Cathodic currents of NB reduction enhanced the diazine-modified SPEs. • The best NB response was obtained by using co-polymerization of the receptor layer. • The low detection limit 0.107 μM allows NB in honey samples to be detected. • The analysis of spiked probes showed the high precision of the sensor with HPLC. In this work, a screen-printed electrode (SPE) modified by 1,3/1,4-diazines was prepared for the rapid and sensitive determination of nitrobenzene (NB). The obtained results indicated enhanced cathodic currents of direct NB reduction into hydroxylaminophenol on the diazine-modified SPEs. The enhanced effect was most likely due to the combination of complexation and collisional processes of diazines towards nitroaromatic compounds and also the diazine-modified electrodes' increased electroconductivity. The best electrochemical responses were obtained in square wave voltammetry mode by using the carbazolyl substituted diazines as a component of the sensitive layer, which was assembled by co-electropolymerization with the unsubstituted carbazole on the electrode during 5 cycles. The low detection limit estimated as 0.107 μM and wide linear range (1–1000 µM) enables NB in water and food samples to be determined. The developed modified electrode was applied in the analysis of commercial honey samples. [ABSTRACT FROM AUTHOR]

A series of novel D–A and D–π–A push-pull systems based on a pyrazine and quinoxaline acceptor, bearing various electron-donating triphenylamine and carbazole moieties, are compared. A significant difference in electrochemical and photophysical properties was found depending on molecular structure. The compounds have strong solvatochromic properties. Quinoxaline-containing systems exhibit delayed fluorescence (DF) in thermal vacuum deposition films. Despite the low quantum yield of fluorescence in the solid state (less than 10%), organic light-emitting diodes with sufficiently high efficiency (4.2 cd/A) have been fabricated on the basis of this push-pull systems. The best results were obtained for compounds exhibiting DF. The possible channel for increasing the efficiency of OLED can be associated with the "hot excitons" mechanism. Image 1 • 1,4-Diazine-based D–(π)–A emitters were synthesized and investigated. • Non-doped OLEDs achieved maximum current efficiency up to 4.2 cd/A. • Yellow OLEDs demonstrating maximum brightness up to 3.2 × 104 cd/m2. [ABSTRACT FROM AUTHOR]