title: Efficient synthesis of high purity homo-arm and mikto-arm poly(ethylene glycol) stars using epoxide and azide-alkyne coupling chemistry.
abstract: High purity homo-arm and mikto-arm poly(ethylene glycol) (PEG) stars are successfully prepared by the combination of epoxide ring-openings and azide-alkyne click reactions. First, monohydroxy-PEG was modified via epoxide chemistry to bear one hydroxyl and one azide functionality at the same end. An alkyne-functionalized PEG chain was then coupled to the azide. Subsequently, the remaining hydroxyl could be reactivated to an azide again and again to enable stepwise addition of alkyne-functionalized polymer arms. The use of efficient reactions for this iterative route provides star polymers with an exact number of arms, and a tailorable degree of polymerization for each arm. Detailed characterization confirms the high purity of multi-arm polyethylene glycol products.
authors.affiliation: Department of Chemistry, Tulane University, New Orleans, LA, 70118, USA.
authors.forename: Boyu
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Tulane University, New Orleans, LA, 70118, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Tulane University, New Orleans, LA, 70118, USA.
authors.forename: Ravinder
authors.initials: R
authors.lastname: Elupula
authors.affiliation: Department of Physics, Tulane University, New Orleans, LA, 70118, USA.
authors.forename: Alina M
authors.initials: AM
authors.lastname: Alb
authors.affiliation: Department of Chemistry, Tulane University, New Orleans, LA, 70118, USA.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Grayson
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D001386:Azides / Q000737:chemistry*; D004852:Epoxy Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D011092:Polyethylene Glycols / Q000138:chemical synthesis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000480:Alkynes; D001386:Azides; D004852:Epoxy Compounds; D011092:Polyethylene Glycols
keywords: epoxide ring opening; homo-arm star polymers; mikto-arm star polymers; poly(ethylene glycol); stepwise CuAAC click coupling