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.

The effect of ligand structure on the catalytic activity of amine-bis(phenolate) chromium(III) complexes in the ring-opening copolymerization of phthalic anhydride and a series epoxides was studied. Eight complexes differing in the donor-pendant group (R₁) and substituents (R₂) in phenolate units were examined as catalysts of the model reaction between phthalic anhydride and cyclohexane oxide in toluene. They were used individually or as a part of the binary catalytic systems with nucleophilic co-catalysts. The co-catalyst was selected from the following organic bases: PPh₃, DMAP, 1-butylimidazole, or DBU. The binary catalytic systems turned out to be more active than the complexes used individually, and DMAP proved to be the best choice as a co-catalyst. When the molar ratio of [PA]:[epoxide]:[Cr]:[DMAP] = 250:250:1:1 was applied, the most active complex (R₁-X = CH₂NMe₂, R₂ = F) allowed to copolymerize phthalic anhydride with differently substituted epoxides (cyclohexene oxide, 4-vinylcyclohexene oxide, styrene oxide, phenyl glycidyl ether, propylene oxide, butylene oxide, and epichlorohydrin) within 240 min at 110 °C. The resulting polyesters were characterized by M_n up to 20.6 kg mol⁻¹ and narrow dispersity, and they did not contain polyether units.

Novel multifunctional one-component catalysts for the cycloaddition of CO₂ to epoxides. The selective and effective conversion of substrates to cyclic carbonates possible using 0.01 mol% catalyst and a low CO₂ pressure.