title: Thioether-Bearing Hyperbranched Polyether Polyols with Methionine-Like Side-Chains: A Versatile Platform for Orthogonal Functionalization.
abstract: The synthesis of thioether-bearing hyperbranched polyether polyols based on an AB/AB2type copolymerization (cyclic latent monomers) is introduced. The polymers are prepared by anionic ring-opening multibranching copolymerization of glycidol and 2-(methylthio)ethyl glycidyl ether (MTEGE), which is conveniently accessible in a single etherification step. Slow monomer addition provides control over molecular weights. Moderate dispersities (Đ = 1.48-1.85) are obtained, given the hyperbranched structure. In situ1H NMR copolymerization kinetics reveal reactivity ratios of rG= 3.7 and rMTEGE= 0.27. Using slow monomer addition, copolymer composition can be systematically varied, allowing for the adjustment of the hydroxyl/thioether ratio, the degree of branching (DB = 0.36-0.48), thermal properties, and cloud point temperatures in aqueous solution in the range of 29-75 °C. Thioether oxidation to sulfoxides enables to tailor the copolymers' solubility profile. Use of these copolymers as a versatile, multifunctional platform for orthogonal modification is highlighted. The methyl sulfide groups can be selectively alkoxylated, using propylene oxide, allyl glycidyl ether, or furfuryl glycidyl ether, resulting in functional hyperbranched polyelectrolytes. Reaction of the alcohol groups with benzyl isocyanate demonstrates successful orthogonal functionalization.
authors.affiliation: Institute of Organic Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128, Mainz, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Seiwert
authors.affiliation: Institute of Organic Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128, Mainz, Germany.|Graduate School Materials Science in Mainz (MAINZ), Staudinger Weg 9, 55128, Mainz, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Herzberger
authors.affiliation: Institute of Organic Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128, Mainz, Germany.|Graduate School Materials Science in Mainz (MAINZ), Staudinger Weg 9, 55128, Mainz, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Leibig
authors.affiliation: Institute of Organic Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128, Mainz, Germany.|Graduate School Materials Science in Mainz (MAINZ), Staudinger Weg 9, 55128, Mainz, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Frey
mesh_terms: D004987:Ethers / Q000737:chemistry*; D008715:Methionine / Q000737:chemistry*; D015394:Molecular Structure; D058105:Polymerization; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013696:Temperature
chemical_list: D004987:Ethers; D011108:Polymers; D013438:Sulfhydryl Compounds; C024617:polyol; D008715:Methionine
keywords: hyperbranched; orthogonal functionalization; polyethers; polyglycerols; polyols; thioethers