Cyclic voltammetry is used to study the electrocatalytic activity in the formation of molecular hydrogen with condensed heterocyclic compounds 1,10-phenatroline and its derivatives 2,9-dimethyl-1,10-phenanthroline and 3,4,7,8-tetramethyl-1,10-phenanthroline using CF3COOH. It is shown that the efficiency and mechanism of electrocatalysis depend strongly on the nature of the catalyst. Raising the number of methyl substituents in the heterocyclic framework improves the efficiency of the process (to more than the TOF value). Mechanisms of the processes are studied and key intermediates are identified via DFT within the context of the density functional theory (DFT) using the B3LYP hybrid functional in the 6-31++G basis.

The electrochemical and electrocatalytic properties of 1-hydro-1,10-phenanthrolinium and 1,10-dihydro-1,10-phenanthrolinium perchlorates in formation of molecular hydrogen in the presence of CF3COOH were studied by cyclic voltammetry. The presence of hydrogen atoms at nitrogen atoms in the heterocyclic compounds strongly influences the electrochemical properties of the compounds and the efficiency of the electrocatalytic process. In going from 1-hydro-1,10-phenanthrolinium perchlorate to 1,10-dihydro-1,10-phenanthrolinium perchlorate, the process efficiency increases (TOF and TON values are higher), despite identical mechanisms. The reaction mechanisms were studied by DFT, and the key intermediates were revealed.

The article shows, for the first time, an example of the manifestation of electrocatalytic activity in the hydrogen evolution reaction (HER) in a new class of organic, metal -free electrocatalysts called "organic hydrides." These organic hydrides are derivatives of the compound 4,4 '-dihydropyridine - 1,1'-(2,6-dimethyl-1,4-dihydropyridin3,5-diyl)bis(ethan-1-one). The electrocatalytic activity of the organic hydride was studied in the presence of acetic and trifluoroacetic acid. It has been shown that the pK value of the acid used determines the HER mechanism. Based on kinetic data, isotope exchange data, as well as density functional theory (DFT)-based calculations, it is shown that the formation of molecular hydrogen proceeds through three different mechanisms depending on the nature of the acid: in the case of using acetic acid, the process goes through the stage of bimolecular elimination; when using trifluoroacetic acid at potential E = -1.0 V, it goes through the stage of intramolecular elimination; whereas at E = -1.6 V, it proceeds through a heterogeneous mechanism.

The possibility of conjugate electroreduction of carbon dioxide and hydrogen in the presence of 2,2'-bipyridine and its N -substituted salts in the presence of acids with different pKa values was studied. It was revealed how the strength of the acid affects the efficiency of the process; in particular, it was determined that the presence of methylsulfonic acid in the system promotes the conjugate formation of hydrogen and the reduction of carbon dioxide to formic acid. Probable mechanisms for the reactions occurring have been proposed.

The possibility of the coupled electrochemical reduction of carbon dioxide and hydrogen in the presence of 2,2'-bipyridine and its N -substituted salts in the presence of acids with different p K a values was studied. It was found that the strength of the acid affects the efficiency of the process; in particular, methylsulfonic acid promotes the coupled hydrogen formation and the reduction of carbon dioxide to formic acid. Plausible mechanisms of the reactions that occurred have been proposed.

2,5-Disubstituted 1,4-bis(4,5-diphenyl-1H-imidazol-2-yl)benzenes have been synthesized, and their electrochemical properties have been studied by cyclic voltammetry, in particular the effect of substituents on the redox characteristics has been examined. The reversible electrochemical redox transformation quinone–biradical of the title compounds occurs at positive potentials.

The electrocatalytic activity in the reaction of hydrogen evolution (HER) of new members of the family of metal-free electrocatalysts - 2,4,6-triphenylpyridine and 2,4,6-triphenylpyrillium perchlorate was studied. Using the method of cyclic voltammetry, preparative electrolysis and gas chromatography analysis the electrochemical behavior of electrocatalysts in the presence of acids of various strength (methanesulfonic, chloric, trifluoroacetic, acetic and triethylammonium hydrochloride) were studied. It has been shown that in the presence of chloric, methanesulfonic and trifluoroacetic acid, 2,4,6-triphenylpyridine has a high catalytic activity (TOF 76, 66.3, 63.2, respectively), while 2,4,6-triphenylpyrillium perchlorate does not. In the presence of weak acids (acetic and triethylammonium hydrochloride), instead of the expected process of formation of molecular hydrogen, the main products of the cathodic electrochemical process were the formation of 2,4,6-triphenyl-1,4-dihydropyridine. The influence of the nature of a heteroatom on of a catalytic process is determined: it is shown that the stage of protonation of electrochemically generated radicals on the heteroatom is key in the electrocatalytic HER process.

A new approach to the preparation of a nanosized sorbent based on magnesium phosphate has been developed. The patterns of copper(II) ions sorption with nanosized magnesium phosphate from aqueous solutions have been investigated. The sorption parameters have been determined, and the kinetics and mechanism of the processes have been elucidated. The high sorption ability of the nanoscale sorbent has been shown in comparison with existing sorbents based on magnesium phosphate.

Immobilization of acridine and its derivatives (9-phenylacridine and N -methyl-9-phenylacridinium iodide) has been studied and quantitative data on physical adsorption have been obtained. The adsorption equilibrium constants K , the parameters A ∞ and Δ G ads have been calculated from the Langmuir adsorption isotherms. The electrochemical properties of organic compounds immobilized on a carbon material surface have been studied by means of cyclic voltammetry.