title: Stille Catalyst-Transfer Polycondensation Using Pd-PEPPSI-IPr for High-Molecular-Weight Regioregular Poly(3-hexylthiophene).
abstract: A commercially available palladium N-heterocyclic carbene (Pd-NHC) precatalyst is used to initiate chain-growth polymerization of 2-bromo-3-hexyl-5-trimethylstannylthiophene. The molecular weight of the resultant poly(3-hexylthiophene) can be modulated (7 to 73 kDa, Đ = 1.14 to 1.53) by varying the catalyst concentration. Mass spectrometry data confirm control over the polymer end groups and (1)H NMR spectroscopy reveals that the palladium catalyst is capable of "ring-walking". A linear relationship between Mn and monomer conversion is observed. Atomic force microscopy and X-ray scattering verify the regioregular nature of the resultant polythiophene.
authors.affiliation: Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, 15213, USA.
authors.forename: Yunyan
authors.initials: Y
authors.lastname: Qiu
authors.forename: Jacob
authors.initials: J
authors.lastname: Mohin
authors.forename: Chia-Hua
authors.initials: CH
authors.lastname: Tsai
authors.forename: Stephanie
authors.initials: S
authors.lastname: Tristram-Nagle
authors.forename: Roberto R
authors.initials: RR
authors.lastname: Gil
authors.forename: Tomasz
authors.initials: T
authors.lastname: Kowalewski
authors.forename: Kevin J T
authors.initials: KJ
authors.lastname: Noonan
mesh_terms: D002384:Catalysis; D009682:Magnetic Resonance Spectroscopy; D010165:Palladium / Q000737:chemistry*; D013876:Thiophenes / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: D013876:Thiophenes; C507295:poly(3-hexylthiophene); D010165:Palladium
keywords: N-heterocyclic carbenes; Stille polycondensation; catalyst-transfer polycondensation; controlled polymerization; poly(3-hexylthiophene)