Pulsed laser polymerisation studies of methyl methacrylate in the presence of AlCl₃ and ZnCl₂ – evidence of propagation catalysis

Abstract

Pulsed laser polymerization experiments demonstrate that Lewis acids electrostatically catalyse the propagation step in radical polymerization of methyl methacrylate.

Isotactic Regulation in the Radical Polymerization of Calcium Methacrylate: Is Multiple Chelation the Key to Stereocontrol?

“…Theoretical calculations also indicated that the coordination of Li + to the ester moiety of a unimeric MMA radical increased the radical stabilization energy (RSE) by between 5 and 8 kJ mol −1 , depending on the extent of cation solvation . We subsequently showed that catalysis could be enhanced through the use of Lewis acids with higher charges such as AlCl 3 and ZnCl 2 . Similar catalysis was also recently reported in the LiNTf 2 ‐mediated radical polymerization of N,N‐dimethylacrylamide, which suggests that such catalysis may be relevant to a wide‐array of polar systems.…”

Internal Oriented Electric Fields as a Strategy for Selectively Modifying Photochemical Reactivity

“…To date these challenges have been overcome on the nanoscale using surface chemistry techniques in conjunction with scanning tunneling microscopy, , but movement toward larger scale systems involving electrodes or charged insulators has been limited to unimolecular reactions and/or surface-tethered systems. − A more promising approach to applying electrostatic effects to solution chemistry is by introduction of charged functional groups (CFGs) to a specific region of a molecule . Typically these CFGs are Brønsted acids and bases in their relevant protonation states, although charged ligands, Lewis acids, and ionic aggregates are also recognized as having potential as electrostatic catalysts.…”

“…5−7 A more promising approach to applying electrostatic effects to solution chemistry is by introduction of charged functional groups (CFGs) to a specific region of a molecule. 8 Typically these CFGs are Brønsted acids and bases in their relevant protonation states, although charged ligands, 9 Lewis acids, 10 and ionic aggregates 11 are also recognized as having potential as electrostatic catalysts.…”

Electrostatic Switching between SN1 and SN2 Pathways

“…Experiments have shown that this can be achieved at the nanoscale using scanning tunneling microscopy, 4,5 and, at larger scales, using electrodes 6 charged insulators, 7 charged functional groups, [8][9][10] and metal ions. [11][12][13] While catalysis has been the main focus until now, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] perhaps the most interesting applications stem from the ability of electric fields to change outcome of a reaction. For instance, theoretical studies have shown that the regio-and stereoselectivity of a Diels-Alder reaction can be changed with either external oriented fields 16,17 or appropriately placed charged functional groups.…”