A Cation-Dependent Dual Activation Motif for Anionic Ring-Opening Polymerization of Cyclic Esters
Caleb N. Jadrich, Vince E. Pane, Binhong Lin, Gavin O. Jones, James L. Hedrick, Nathaniel H. Park, Robert M. Waymouth
Abstract
A new organocatalyst for the ring-opening polymerization of lactones has been identified. Under the tested conditions, the anions of 2,2'-bisindole promote fast, living polymerizations (as short as 10 ms) which are selective for chain elongation over transesterification (Đ ≤ 1.1). While structurally related to (thio)urea anion catalysts, anions of 2,2'-bisindole activate the monomer via the counterion rather than through hydrogen bonding. This new activation motif enables modulation of the polymerization rate by 2 orders of magnitude by changing the counterion.
Topics & Concepts
ChemistryPolymerizationPolymer chemistryMotif (music)Ring-opening polymerizationRing (chemistry)StereochemistryOrganic chemistryPolymerPhysicsAcousticsbiodegradable polymer synthesis and propertiesCarbon dioxide utilization in catalysisAdvanced Polymer Synthesis and Characterization