Quantum chemical calculation driven insights into deep eutectic solvent‐accelerated photoinduced reversible complexation‐mediated polymerization

• Published in: AIChE journal 2024-05, Vol.70 (5), p.n/a
• Main Authors: Li, Shen, Fu, Xin, Zhou, Yin‐Ning, Liu, Zhong‐Xin, Hou, Lin‐Xi, Luo, Zheng‐Hong
• Format: Article
• Language: English
• Subjects: Complexation; controlled radical polymerization; Decomposition; Decomposition reactions; deep eutectic solvent; Free energy; Hydrogen bonds; Iodides; Iodine; Irradiation; kinetic modeling; Light irradiation; Method of moments; Modelling; Photocatalysts; photochemistry; Polymerization; Polymers; Quantum chemistry; Radiation; Radicals; Solvents
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.18372

Deep eutectic solvent (DES) is used as both photocatalyst and solvent for photoinduced reversible complexation‐mediated polymerization (photo‐RCMP), which enables a rapid polymerization to produce polymers with predictable molar mass and low molar mass dispersity (Đ). This work illustrates a comprehensive understanding of DES‐accelerated RCMP's mechanism and kinetic features through quantum chemical calculations and kinetic modeling. According to the results, electrons transferring from hydrogen bond in DES to iodine atom in alkyl iodide (RI) initiator under light irradiation lowers the decomposition free energy of complex RI‐DES. This procedure facilitates the generation of primary radicals, thus contributing to the DES‐accelerated phenomenon. In the meantime, the reaction paths are identified by computation as (i) decomposition of RI‐DES under light irradiation generates active radicals and ·I‐DES complex and (ii) combination of two ·I‐DES releases iodine (I2) and regenerates DES. In addition, kinetic modeling based on the method of moments successfully identifies kinetic features of polymerization in the presence and absence of DES, respectively. Kinetic modeling shows a fast increase in primary radicals concentration and rapid build‐up of the photo‐RCMP activation‐deactivation equilibrium, demonstrating that DES is a beneficial photocatalyst and solvent to enable the rapid generation of primary radicals and accelerate the completion of catalytic cycle. This research provides an in‐depth understanding of DES‐involved photo‐RCMP and lays a theoretical foundation for expanding the application of DES to other polymerization systems.