title: A Simple and Facile Approach to Aliphatic N-Substituted Functional Eight-Membered Cyclic Carbonates and Their Organocatalytic Polymerization.
abstract: Aliphatic N-substituted functional eight-membered cyclic carbonates were synthesized from N-substituted diethanolamines by intramolecular cyclization. On the basis of the N-substituent, three major subclasses of carbonate monomers were synthesized (N-aryl, N-alkyl and N-carbamate). Organocatalytic ring opening polymerization (ROP) of eight-membered cyclic carbonates was explored as a route to access narrowly dispersed polymers of predictable molecular weights. Polymerization kinetics was highly dependent on the substituent on the nitrogen atom and the catalyst used for the reaction. The use of triazabicyclodecene (TBD), instead of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), as the catalyst for the N-alkyl substituted monomers significantly enhanced the rate of polymerizations. Computational studies were performed to rationalize the observed trends for TBD catalyzed polymerizations. With the optimal organocatalyst all monomers could be polymerized generating well-defined polymers within a timespan of ≤2 h with relatively high monomer conversion (≥80%) and low molar-mass dispersity (Đ(M) ≤ 1.3). Both the glass transition temperatures (T(g)) and onset of degradation temperatures (T(onset)) of these polymers were found to be N-substituent dependent and were in the range of about -45 to 35 °C and 230 to 333 °C, respectively. The copolymerization of the eight membered monomers with 6-membered cyclic comonomers including commercially available l-lactide and trimethylene carbonate produced novel copolymers. The combination of inexpensive starting materials, ease of ring-closure and subsequent polymerization makes this an attractive route to functional polycarbontes.
authors.affiliation: Institute of Bioengineering and Nanotechnology , 31 Biopolis Way, The Nanos, Singapore 138669, Singapore.
authors.forename: Shrinivas
authors.initials: S
authors.lastname: Venkataraman
authors.affiliation: Institute of Bioengineering and Nanotechnology , 31 Biopolis Way, The Nanos, Singapore 138669, Singapore.
authors.forename: Victor W L
authors.initials: VW
authors.lastname: Ng
authors.affiliation: IBM Almaden Research Center , 650 Harry Road, San Jose, California 95120, United States.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Coady
authors.affiliation: IBM Almaden Research Center , 650 Harry Road, San Jose, California 95120, United States.
authors.forename: Hans W
authors.initials: HW
authors.lastname: Horn
authors.affiliation: IBM Almaden Research Center , 650 Harry Road, San Jose, California 95120, United States.
authors.forename: Gavin O
authors.initials: GO
authors.lastname: Jones
authors.affiliation: Institute of Bioengineering and Nanotechnology , 31 Biopolis Way, The Nanos, Singapore 138669, Singapore.
authors.forename: Tak Shun
authors.initials: TS
authors.lastname: Fung
authors.affiliation: POLYMAT, University of the Basque Country UPV/EHU Joxe Mari Korta Center , Avda. Tolosa 72, 20018 Donostia-San Sebastián, Spain.
authors.forename: Haritz
authors.initials: H
authors.lastname: Sardon
authors.affiliation: Department of Chemistry, Stanford University , Stanford, California 94305, United States.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Waymouth
authors.affiliation: IBM Almaden Research Center , 650 Harry Road, San Jose, California 95120, United States.
authors.forename: James L
authors.initials: JL
authors.lastname: Hedrick
authors.affiliation: Institute of Bioengineering and Nanotechnology , 31 Biopolis Way, The Nanos, Singapore 138669, Singapore.
authors.forename: Yi Yan
authors.initials: YY
authors.lastname: Yang