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.

Objectives: Salophen-type Schiff bases functionalized with 4-(dimethylamino)pyridinium halide units are shown to be effective single-component catalysts for the synthesis of cyclic carbonates from terminal epoxides and carbon dioxide. Methods: Using one of such trifunctional organocatalysts, epichlorohydrin could be selectively converted to the target cyclic carbonate under 2 bar of CO₂ at 120 °C. Results: Over 80% conversion of E3 was then observed when organocatalyst S3 was used in the amount of 0.5 mol% (TON = 156) and even the use of 0.05 mol% S3 guaranteed almost 50% conversion of E3 to C3 (TON = 893). Conclusions: The presence of tertiary amine units in the molecules of these homogeneous organocatalysts proved to be crucial for the catalytic activity of developed organocatalysts. However, their catalytic activity was also supported by the presence of acidic phenolic units and halide ions as Lewis bases. Some closely related compounds were found to be clearly less active or inactive catalytically under the applied reaction conditions.