The effect of a ligand structure on the catalytic activity of salophen chromium(III) complexes in the ring-opening copolymerization of phthalic anhydride with a series of epoxides was studied. The catalytic activity of ten differently substituted complexes was explored in the copolymerization reactions conducted in toluene solutions using equimolar mixtures of monomers. The experiments were performed both with and without DMAP addition as a co-catalyst. The presence of F or Me substituents in the moieties of 1,2-phenylenediamines increased the activity of the complexes. An increase in the complex activity was also found with decreasing the donor character of substituents in salicylaldehyde moieties (in the order OMe < tBu < H). When the molar ratio of [PA] : [epoxide] : [Cr] : [DMAP] = 250 : 250 : 1 : 1 was applied, the most active complexes allowed the copolymerization of phthalic anhydride with differently substituted epoxides (cyclohexene oxide, 4-vinylcyclohexene oxide, styrene oxide, phenyl glycidyl ether, propylene oxide, butylene oxide, epichlorohydrin) quantitatively within 60 minutes at 110 °C. The resulting polyesters were characterized by M_n up to 19 kg mol⁻¹ and narrow dispersity, and they did not contain polyether units.

Ni(II) complexes with (±)-trans-N,N′-bis(salicylidene)-1,2-cyclohexanediamine ([Ni(salcn)]), and its methyl ([Ni(salcn(Me))]) and tert-butyl ([Ni(salcn(Bu))]) derivatives have been synthesized. Anodic electropolymerization has been used to form electrodes modified by polymer films. FTIR and FTIR ATR methods showed that the obtained films consist of polymers of phenyl–phenyl type. The structure of poly[Ni(salcn)] is built with 1,2,4- and 1,2,3,5-substituted chains. A three-step process of the oxidation of the complexes and their films has been ascertained on the basis of cyclic voltammetry measurements. Furthermore we have also detected the oxidized species which probably serve as intermediates for polymer formation. The influence of the substituent in the phenolate moiety on the type of reaction after which the dimerization and polymerization reaction occurs has been evidenced. Furthermore the substituent dependence on the stability of the phenoxyl radical complex and the Ni(II)-phenoxonium cation has been noticed. For the [Ni(salcn(Bu))] complex, an additional electropolymerization step – the adsorption of the reagent on the electrode surface – has been observed.

Manganese(II) complexes with phenanthroline derivatives modified with different substituents were synthesized and incorporated into Nafion layers covering the surfaces of glassy carbon electrodes and were studied electrochemically. Formal potentials and apparent diffusion coefficients were calculated and discussed. The suitability for electrocatalytic oxidation of ascorbic acid and glycolic acid was examined. The surfaces of modified electrodes were characterized using atomic force microscopy.

Platinum electrodes were modified with polymers of the (±)-trans-N,N′-bis(salicylidene)-1,2-cyclohexanediaminenickel(II) ([Ni(salcn)]) and (±)-trans-N,N′-bis(3,3′-tert-Bu-salicylidene)-1,2-cyclohexanediaminenickel(II) ([Ni(salcn(Bu))]) complexes to study their electrocatalytic and electroanalytical properties. Poly[Ni(salcn)] and poly[Ni(salcn(Bu))]) modified electrodes catalyze the oxidation of catechol, aspartic acid and NO₂⁻. In the case of poly[Ni(salcn)] modified electrodes, the electrocatalysis process depends on the electroactive surface coverage. The films with low electroactive surface coverage are only a barrier in the path of the reducer to the electrode surface. The films with more electroactive surface coverage ensure both electrocatalysis inside the film and oxidation of the reducer directly on the electrode surface. In the films with the most electroactive surface coverage, electrocatalysis occurs only at the polymer–solution interface. The analysis was based on cyclic voltammetry, EQCM (electrochemical quartz crystal microbalance) and rotating disc electrode method.

Electrodes modified with polymers derived from the complexes [Ni(salcn)], [Ni(salcn(Me))] and [Ni(salcn(Bu))] were obtained in order to study the kinetics of electrode processes occurring in polymer films, depending on the thickness of the films, the type of electrolyte and the solvent. FTIR and EQCM methods were used to determine the type of mass transported into polymer films during anode processes and the number of moles of ions and solvent. The rate of charge transport through films was determined by the cyclic voltammetry method, by the quantity cD^1/2. It was shown that the charge transport was determined by the transport of anions. The kinetics were most efficient for poly[Ni(salcn(Bu))] modified electrodes, obtained from TBAPF₆ and working in TBAClO₄ and TBABF₄. It was also shown that a solvent with a higher DN value and lower viscosity (MeCN) facilitated the transport of the charge through polymer films.

The voltammetry and chronocoulometry methods were used in the research of kinetics of redox processes occurring on electrodes modified with conductive polymers, derived from the following complexes: (±)-trans- N,N’-bis(salicylidene)-1,2-cyclohexanediaminenickel(II) (poly[Ni(salcn)]), ((±)-trans-N,N’-bis(3,-methylsalicylidene)-1,2-cyclohexanediaminenickel(II) (poly[Ni(salcn(Me))]) and ((±)-trans-N,N’-bis(3,-tert-butylsalicylidene)-1,2-cyclohexanediaminenickel(II) (poly[Ni(salcn(Bu))]). Spectroelectrochemical method and chronopotentiometry were used to determine the mechanisms of redox processes. In poly[Ni(salcn)] and poly[Ni(salcn(Bu))] the ligand is oxidized, whereas in poly[Ni(salcn(Me))] both the ligand and the central ion are oxidized. The processes take place according to the EE mechanism. The poly[Ni(salcn)] and poly[Ni(salcn(Me))] films of thickness obtained as a result of 1–30 electropolymerization cycles, as well as poly[Ni(salcn(Bu))] of thickness obtained as a result of up to 150 cycles were studied. The investigated films of each complex are limited by surface processes, diffusion and surface-diffusion processes, depending on the film thickness. For the films that generate surface-diffusion processes, the boundaries of such processes have been determined. For the diffusion processes, the boundaries of semi-infinite diffusion regime and finite diffusion regime have been defined. On this basis, the cD^1/2 value for anode and cathode processes providing semi-infinite diffusion conditions has been determined as a criterion for selection of the optimal conditions for modification of the electrodes.