Ring-opening polymerization of cyclic compounds catalyzed by carbene derivatives

A method for ring-opening polymerization of cyclic compounds, comprising:

• providing a cyclic compound, wherein the cyclic compound is a macrocyclic oligomer, wherein the macrocyclic oligomer is obtained by prepolymerization of one or more cyclic monomers chosen from:
• wherein A is [—(CR5R6)—]n, in which n is an integer from 2 to 10;
• R5 and R6 are independently chosen from H, alkyl groups with 1 to 5 carbon atoms, and alkyl groups having 1 to 5 carbon atoms with substituents chosen from halogens or a hydroxyl group;
• and X is chosen from O and N;
• polymerizing a reaction mixture comprising the macrocyclic oligomer, an alcohol initiator, and a carbon dioxide adduct of carbene, wherein the reaction mixture is solvent-free,
• wherein the carbon dioxide adduct of carbene has a structure represented by formula (I)
• wherein the dotted line together with the solid line parallel to the dotted line represents a single bond or a double bond;
• X1 is chosen from S and N;
• X2 is chosen from C and N;
• R1, R2, R3, and R4 satisfy at least one of the following conditions:
• (I) R1 and R2 are independently chosen from
• hydrogen,
• alkyl groups having 1 to 10 carbon atoms,
• alkyl groups having 1 to 10 carbon atoms and one or more substituents chosen from halogens, a hydroxyl group, a phenyl group, and a cyano group,
• cycloalkyl groups having 3 to 6 carbon atoms,
• a halogen atom,
• an adamantane group,
• a phenyl group, and
• a substituted phenyl group;
• (II) R3 and R4 are independently chosen from
• hydrogen,
• a halogen atom,
• a cyano group,
• a hydroxyl group,
• alkyl groups having 1 to 4 carbon atoms,
• alkyl groups having 1 to 4 carbon atoms and one or more substituents chosen from halogens, a hydroxyl group, a phenyl group, and a cyano group,
• a phenyl group, and
• a substituted phenyl group;
• (III) R3 and R4 are connected to form cycloalkyl or cycloalkenyl rings having 3 to 8 carbon atoms fused to the five-membered ring that contains X1, X2, and the nitrogen atom (in which case X2 and the carbon atom in the 5-membered ring next to X2 are also part of said cycloalkyl or cycloalkenyl rings);
• (IV) R3 and R4 are connected to form a benzene ring fused to the five-membered ring that contains X1, X2, and the nitrogen atom (in which case X2 and the carbon atom in the 5-membered ring next to X2 are also part of said benzene ring);
• and
• (V) R2 and R3 are connected to form a 5-membered or 6-membered N-heterocyclic ring having no substituent, which is fused to the five-membered ring that contains X1, X2, and the nitrogen atom (in which case X1 and the carbon atom in the 5-membered ring connected to R3 are also part of said 5-membered or 6-membered N-heterocyclic rings, R1 is a group as defined in condition (I), and R4 is a group as defined in condition (II)).