title: Highly selective molybdenum ONO pincer complex initiates the living ring-opening metathesis polymerization of strained alkynes with exceptionally low polydispersity indices.
abstract: The pseudo-octahedral molybdenum benzylidyne complex [TolC≡Mo(ONO)(OR)]·KOR (R = CCH3(CF3)2) 1, featuring a stabilizing ONO pincer ligand, initiates the controlled living polymerization of strained dibenzocyclooctynes at T > 60 °C to give high molecular weight polymers with exceptionally low polydispersities (PDI ∼ 1.02). Kinetic analyses reveal that the growing polymer chain attached to the propagating catalyst efficiently limits the rate of propagation with respect to the rate of initiation (kp/ki ∼ 10(-3)). The reversible coordination of KOCCH3(CF3)2 to the propagating catalyst prevents undesired chain-termination and -transfer processes. The ring-opening alkyne metathesis polymerization with 1 has all the characteristics of a living polymerization and enables, for the first time, the controlled synthesis of amphiphilic block copolymers via ROAMP.
authors.affiliation: Department of Chemistry, University of California Berkeley , Berkeley, California 94720, United States.
authors.forename: Donatela E
authors.initials: DE
authors.lastname: Bellone
authors.forename: Justin
authors.initials: J
authors.lastname: Bours
authors.forename: Elisabeth H
authors.initials: EH
authors.lastname: Menke
authors.forename: Felix R
authors.initials: FR
authors.lastname: Fischer