Sequential and alternating RAFT single unit monomer insertion: model trimers as the guide for discrete oligomer synthesis

Abstract

A complete set of model trimers and their synthetic kinetics are established to guide the synthesis of diverse sequence-defined polymers.

Unraveling Sequence Effect on Glass Transition Temperatures of Discrete Unconjugated Oligomers

“…Meanwhile, the F monomer has higher rigidity than the Q monomer, which is attributed to the strong electronic repulsion between the two cyanide (-CN) electron withdrawing groups. [57][58] As a result, the T g value for F-I-F is higher (30 °C) than that of Q-I-Q. This structural effect also applied to the other three pairs of trimers listed in Figure 1a.…”

“…The monomers were sequentially inserted into a trithiocarbonate (n-butyl-1-phenylethyl trithiocarbonate, BETC) via designed donor-acceptor sequences in the presence photocatalyst (5,10,15,20-tetraphenyl21H,23Hporphine zinc (ZnTPP) under the red light irradiation, which have been synthesized in high isolated yields without great difficulties. [57] The molecular structures of these trimers are shown in Figure 1a. The electron-donating I monomer is placed in the middle of the trimer without variation.…”

“…[73][74] Taking Pair 2 (M-I-Q and Q-I-M) as an example, their T g s have a 10.5 °C difference (35.2 vs 24.7 °C). Considering the compatibility of the bulk polymer materials with the plasticizers, the ideal polymers are those possessing similar polymer structures, such as the copolymer of I and M. To demonstrate the concept we employed a model pentamer that we prepared in our previous study, [57] M-I-M-I-M (Figure 4a), as the parent polymer to blend with the pair of trimers. The monodisperse pentamer has a defined molecular weight and molecular composition, which is preferable to a high molecular weight polymer with dispersed chain lengths.…”

Aminolysis induced functionalization of (RAFT) polymer-dithioester with thiols and disulfides

“…Especially, reversible addition-fragmentation chain transfer (RAFT) chemistry introduces a handle to modification of polymer materials on demand as recently shown by the synthesis of hydrogels capable of growth in consecutive polymerization steps. 27,28 The reactivity of the RAFT end group can be utilized for end group modifications of polymers, for example, for single unit monomer insertions 29 or removal of the reactive end group. 30 As with other reversible deactivation radical polymerization techniques, the RAFT group has been used to produce block copolymers.…”

A Universal Sequencing System for Unknown Oligomers

“…In addition, achieving sequence-controlled oligomerization in multicomponent reactions remains an elusive goal in polymer chemistry and materials science (15). Several synthetic strategies have emerged for producing sequence-controlled oligomers and polymers, with stepwise (19) and more recently chain growth methods (20) enabling sequence-controlled synthesis of specific oligomers and oligomer libraries. However, no synthetic system to date has come close to matching the fidelity, specificity and turnover of biological systems in their production of complex, sequence-encoded polymers (15).…”