title: Synthesis of Discrete Oligomers by Sequential PET-RAFT Single-Unit Monomer Insertion.
abstract: Uniform synthetic polymers with precisely defined molar mass and monomer sequence (primary structure) have many potential high-value applications. However, a robust and versatile synthetic strategy for these materials remains one of the great challenges in polymer synthesis. Herein we describe proof-of-principle experiments for a modular strategy to produce discrete oligomers by a visible-light-mediated radical chain process. We utilize the high selectivity provided by photo-induced electron/energy transfer (PET) activation to develop efficient single unit monomer insertion (SUMI) into reversible addition-fragmentation chain-transfer (RAFT) agents. A variety of discrete oligomers (single unit species, dimers, and, for the first time, trimers) have been synthesized by sequential SUMI in very high yield under mild reaction conditions. The trimers were used as building blocks for the construction of uniform hexamers and graft copolymers with precisely defined branches.
authors.affiliation: Centre for Advanced Macromolecular Design (CAMD) and Australian Centre for NanoMedicine (ACN), School of Chemical Engineering, UNSW Australia, Sydney, NSW, 2052, Australia.
authors.forename: Jiangtao
authors.identifier: 0000-0002-9020-7018
authors.initials: J
authors.lastname: Xu
authors.affiliation: Centre for Advanced Macromolecular Design (CAMD) and Australian Centre for NanoMedicine (ACN), School of Chemical Engineering, UNSW Australia, Sydney, NSW, 2052, Australia.
authors.forename: Changkui
authors.initials: C
authors.lastname: Fu
authors.affiliation: Centre for Advanced Macromolecular Design (CAMD) and Australian Centre for NanoMedicine (ACN), School of Chemical Engineering, UNSW Australia, Sydney, NSW, 2052, Australia.|Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, USA.
authors.forename: Sivaprakash
authors.identifier: 0000-0001-5954-1336
authors.initials: S
authors.lastname: Shanmugam
authors.affiliation: Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, USA.
authors.forename: Craig J
authors.identifier: 0000-0001-9951-851X
authors.initials: CJ
authors.lastname: Hawker
authors.affiliation: CSIRO Manufacturing, Clayton, VIC, 3168, Australia.
authors.forename: Graeme
authors.identifier: 0000-0002-4375-5580
authors.initials: G
authors.lastname: Moad
authors.affiliation: Centre for Advanced Macromolecular Design (CAMD) and Australian Centre for NanoMedicine (ACN), School of Chemical Engineering, UNSW Australia, Sydney, NSW, 2052, Australia.
authors.forename: Cyrille
authors.identifier: 0000-0002-4564-4702
authors.initials: C
authors.lastname: Boyer
keywords: RAFT polymerization; photopolymerization; sequence control; single unit monomer insertion