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.