A fast semi-continuous anionic process for fluorene-functionalized homo and block oligomers with uniform molecular weights

Abstract

A semi-continuous strategy based on anionic reactions was developed for the step-by-step synthesis of oligomers with uniform molecular weights.

Single Unit Monomer Insertion: A Versatile Platform for Molecular Engineering through Radical Addition Reactions and Polymerization

“…The drawback of this approach is evident in the repetitive and limited chemical functionality of the monomer units; increasing the chemical diversity in the oligomer chains is thus challenging . Chain-growth polymerization presents advantages by providing a diverse choice of monomers and precise location of functionality along the polymer chains, which include ionic polymerization ,, and ring-opening and cross-metathesis polymerization. ,− The details of these approaches are beyond this Perspective, and several comprehensive review articles have summarized recent developments in both step-growth and chain-growth polymerization. ,,− …”

“…As the name itself implies, SUMI is a synthetic technology for the precise assembly of oligomers/polymers through a radical process with monomer additions occurring one at a time. The description of SUMI is pinpointed from the following mechanistic and monomer scopes (Figure ): (1) SUMI operates via a radical chain-growth mechanism; although anionic and cationic polymerizations possess the capability for single monomer additions to the growing chain end, there are very limited monomer examples (e.g., 1,1-diphenylethylene − and Boc-protected 2-aminoethyl vinyl ether , ), with these acting mostly as branching or capping agents to mediate polymerization “on” and “off”. Therefore, these techniques will not be discussed in this Perspective.…”

Thermally Controlled On/Off Switch in a Living Anionic Polymerization of 1-Cyclopropylvinylbenzene with an Anion Migrated Ring-Opening Mechanism

“…A stepwise growth polymerization can effectively reveal the sequence tailoring of monomer units through iterative incorporations of specific monomers. − Thus, sequence-coded functionalized polymers that are mono -dispersed are mainly synthesized by multiple steps of selective coupling reactions. − However, complicated operations and a low productivity rate extremely restrict the synthesis of polymers with a high degree of polymerization. Thus, the challenge is to drive controlled chain-growth polymerization to innovate stepwise growth characteristics that can provide ultraprecise monomer sequences in addition to other inherent advantages.…”

Upscaling single unit monomer insertion to synthesize discrete oligomers

“…Motivated by the desire to prepare such precise structures, an increasing number of innovative physical and chemical approaches have been developed during the past decades, including automated separation system, atom transfer radical addition, click‐based chemistry (thio‐ene, thio‐maleimide, and thiolactone), phosphoramidite chemistry, multicomponent reaction, photo‐ligation chemistry, and ionic polymerization techniques . Most of the elegant examples in these approaches use an iterative exponential growth (IEG) process, which evolves from step‐growth polymerization and uses pre‐protected bifunctional monomers to achieve sequential attachments and doubles the molecular weights of synthetic oligomers/polymers .…”

“…1,2,[12][13][14][15][16] Motivated by the desire to prepare such precise structures, an increasing number of innovative physical and chemical approaches have been developed during the past decades, including automated separation system, [17][18][19][20][21] atom transfer radical addition, [22][23][24][25][26][27] click-based chemistry (thio-ene, thio-maleimide, and thiolactone), [28][29][30][31][32] phosphoramidite chemistry, 12,[33][34][35] multicomponent reaction, [36][37][38][39][40] photo-ligation chemistry, 41 and ionic polymerization techniques. 3,[42][43][44] Most of the elegant examples in these approaches use an iterative exponential growth (IEG) process, 37,38,41,[45][46][47][48][49][50] which evolves from step-growth polymerization and uses pre-protected bifunctional mo...…”