Regio-controlled ring-opening polymerization of perfluoroalkyl-substituted epoxides

Abstract

Highly fluorinated epoxides were polymerized under mild conditions regioregularly, which gave easy access to isotactic polymers by using optically pure epoxides.

Designing Cooperative Hydrogen Bonding in Polyethers with Carboxylic Acid Pendants

“…29,30 It is known that the initiation step can involve hydrogen or the t-butyl group from Al(i-Bu) 3 besides the desired iodine group, as shown in Figure 3a. 31,32 As a representative example, P(t-BGA) 10 (entry 1 in Table 1) was selected to determine the degree of initiation from each group. It can be observed that the majority of the peaks originated from the initiation of iodine; for example, the observed m/z of 2034.25 can be assigned to a homopolymer comprised of the iodine initiator (126.90) and 10 monomers (188.22), with Na + as the counterion (Figure 3b).…”

“…Encouraged by the successful polymerization of the t -BGA monomer using MAROP, we further explored the mechanistic details by analyzing the initiation steps using matrix-assisted laser desorption/ionization-time of flight (MALDI-ToF) analysis (Figures and S13). As demonstrated in previous reports, the MALDI-ToF was employed for evaluation of the absolute molecular weight and end group analysis as well as the polymer topologies, which provides a convenient means to assess the relative contents of polymers with different initiating species. , It is known that the initiation step can involve hydrogen or the t -butyl group from Al­( i -Bu) 3 besides the desired iodine group, as shown in Figure a. , As a representative example, P­( t -BGA) 10 (entry 1 in Table ) was selected to determine the degree of initiation from each group. It can be observed that the majority of the peaks originated from the initiation of iodine; for example, the observed m / z of 2034.25 can be assigned to a homopolymer comprised of the iodine initiator (126.90) and 10 monomers (188.22), with Na + as the counterion (Figure b).…”

Ester Functional Epoxide Monomers for Random and Gradient Poly(ethylene glycol) Polyelectrolytes with Multiple Carboxylic Acid Moieties

“…For higher molar fractions of t BEP (31.1 mol %) less-defined bimodal molecular weight distributions were obtained with a dispersity of 1.76. The bimodal distribution may be caused by undesired late initiation by the Lewis acid, through the transfer of hydrides or isobutyl groups . The de via tion of the molecular weights determined via SEC from the targeted value is similar to the case of the P­(EG- co -MEP) copolymer series.…”

Utilization of catecholic functionality in natural safrole and eugenol to synthesize mussel-inspired polymers

“…Polymerization reaction of 2 using Lewis acid triisobutylaluminium as a catalyst and methyltriphenyphosphonium bromide (I) as an initiator 38,39,52 gave ring opened polymer 6 in excellent yields (Scheme 2), ( Table 1). The 1 H NMR spectra (Fig.…”

“…It is reported that the initiation process involved the attack by not only bromide but also by the isobutyl group and hydride as shown in Scheme 3, 39,52 thereby leading to three polymers having bromide, isobutyl, and hydride end groups. 52 i Bu 3 Al can work both as a hydride as well as an isobutyl anion in the ringopening reaction. 55,56 Generally, propagation via nucleophilic attacks on the less hindered methylene carbon of epoxides leads to regioregular polymers.…”