Use of anN-heterocyclic carbene (NHC)-based interacting Lewis pair for the synthesis of a cyclic poly(alkyl acrylate)viachain-growth polymerization and subsequent ring-closing without extreme dilution

Abstract

The pairing of 1,3-di-tert-butylimidazol-2-ylidene (NHCtBu) and methylaluminum bis(2,6-di-tert-butyl-4-methylphenoxide) (MAD) acted as an interacting Lewis pair (ILP) for anionic polymerization of several acrylates. The ILP showed higher polymerization activity for ethyl...

Facile synthesis of cyclic RAFT agents and ring expansion radical polymerization of vinyl monomers having cyclic topology

“…The samples for TEM were prepared according to our reported protocol. [49][50][51][52] Electrospray ionization mass spectrometry (ESI-MS). The molecular weights of cyclic-TTC were obtained from ESI-MS measurements using a Synapt G2 HDMS + Acquity manufactured by Waters Co. Ltd.…”

Anionic Polymerization of Polar Conjugated Diene Monomers with Phosphine as the Initiator and Subsequent Ring Closure without Highly Dilute Conditions

“…However, because of the complex (Lewis pair) formation of I t Bu and MAD, the initiation efficiency was low (only 50–60%) and the ratio of the diisotactic polymer/disyndiotactic polymer was uncontrolled at 55/45; the diastereoselectivity, however, was almost 90% controlled in the threo structure. In extended studies, we reported the direct observation of the cyclic topology by transmittance electron microscopy (TEM) images and an expansion of the range of acceptable vinyl monomers, including MMA, allyl methacrylate (AMA), N -substituted maleimide (NMI), and acrylates . This research background has now prompted us to explore new organic catalysts that can replace expensive NHCs.…”

“…In extended studies, we reported the direct observation of the cyclic topology by transmittance electron microscopy (TEM) 38 images and an expansion of the range of acceptable vinyl monomers, including MMA, 39 allyl methacrylate (AMA), 40 N-substituted maleimide (NMI), 41 and acrylates. 42 This research background has now prompted us to explore new organic catalysts that can replace expensive NHCs.…”

Base‐assisted anionic polymerization of alkyl sorbates and subsequent ring‐closure without extreme dilution for synthesis of cyclic stereoregular poly(alkyl sorbates)

“…In 2017, we reported that an N ‐heterocyclic carbene, 1,3‐di‐ tert ‐butylimidazol‐2‐ylidene (NHC t Bu), initiated a Lewis acid‐assisted anionic polymerization of methyl sorbate (MS) and subsequent ring‐closure without highly diluted conditions to give the cyclic poly(MS) 11 . In extended work, we demonstrated the production of cyclic poly(methyl methacrylate) (MMA), 12 poly(allyl methacrylate) (AMA), 13 poly( N ‐substituted maleimide), 14 and poly(acrylate)s 15 by using 1:1 reactant of NHC t Bu and MS. We expected that initiation step is nucleophilic addition and inserted NHC t Bu residue acted as a leaving group to give the cyclic polymers after monomer depletion. We also expected ring closure did not require highly diluted conditions thanks to the neighboring α‐terminal NHC t Bu during the polymerization.…”