Metal-free Lewis pairs catalysed synthesis of fluorescently labelled polyester-based amphiphilic polymers for biological imaging

ABA Block Copolyester Thiol–Ene Resin From Triethylborane-Assisted Ring-Opening Copolymerization

“…In agreement with previous reports of Et 3 B/ [PPN]Cl catalyzed ROCOP with or without small-molecule CTAs, M n increases linearly with anhydride conversion and time (Figure 1A,B), validating PPS's linear and uniform chain extension. 21,44 The conversion-M n best-fit curve intercepts the y-axis at 2323 g/mol, approximating the M n of PPS and suggesting negligible epoxide homopolymerization (Figure 1A). GPC traces of polymerization aliquots have an unimodal distribution, with the series of peaks corresponding to low molecular weight PPS oligomer no longer visible.…”

“…20,43 The recent advent of boron-based Lewis-pair-catalyzed ROCOP alleviates the toxicity concern and has demonstrated potential in drug delivery and biological imaging. 44 To produce colorless and stable photopolymers, we used an Et 3 B/[PPN]Cl bicomponent catalyst system. The resultant BC1 prepolymer with 18 wt % of PPS (entry 1, Table 1) has a higher molecular weight than that produced by AlCl.…”

Biodegradable Copolymers from CO2, Epoxides, and Anhydrides Catalyzed by Organoborane/Tertiary Amine Pairs: High Selectivity and Productivity

“…31−38 Furthermore, these organocatalysts could be fully removed from the resultant polymers by simply precipitating them in acidified methanol, 39 and the polymers from these TEB/organic base Lewis pairs are biocompatible in nature with minimal cytotoxicity. 40,41 Later, inspired by the EP/CO 2 ROCOP and EP/AH ROCOP mediated by TEB-based catalyst systems, 42−44 the EP/CO 2 / AH ROCOP was successfully conducted. 45−48 Notably, the most widely studied systems are Lewis pairs consisting of TEB and onium salts, which require excess TEB loadings and display high activity with a TOF value up to 185 h −1 , but the highest productivity did not exceed 250 g polymer/g catalyst.…”

“…After the pioneering work of Feng’s research group in 2016, a series of metal-free Lewis pairs composed of triethylborane (TEB) and organic bases have been developed for the ROCOP of CO 2 with various epoxides even under atmospheric CO 2 , which are commercially available and obviate the metal usage. − Furthermore, these organocatalysts could be fully removed from the resultant polymers by simply precipitating them in acidified methanol, and the polymers from these TEB/organic base Lewis pairs are biocompatible in nature with minimal cytotoxicity. , Later, inspired by the EP/CO 2 ROCOP and EP/AH ROCOP mediated by TEB-based catalyst systems, − the EP/CO 2 /AH ROCOP was successfully conducted. − Notably, the most widely studied systems are Lewis pairs consisting of TEB and onium salts, which require excess TEB loadings and display high activity with a TOF value up to 185 h –1 , but the highest productivity did not exceed 250 g polymer/g catalyst . Other organic bases including guanidine and phosphazene bases were also applied and displayed medium/high activity (76–191 h –1 ).…”

A Facile Fabrication of Lysosome-Targeting pH Fluorescent Nanosensor Based on PEGylated Polyester Block Copolymer

“…On the basis of the above introduction, we propose a concept for the design and synthesis of lysosome-targeting polyester-based amphiphilic polymeric fluorescent pH nanosensors by the ROCOP of epoxide with anhydride catalyzed by metal-free Lewis pairs, a thiol-ene click reaction and subsequent self-assembly. Rhodamine was selected as the fluorescence organic dye due to its highly fluorescent pH-sensitivity [53][54][55][56]. Concurrently, biocompatible polyester-based amphiphilic polymers with abundant alkenyl functional groups, serving as the polymer carriers, can covalently attach rhodamine moieties with controllable grafting degree via an efficient thiol-ene reaction.…”