title: Furan- and Thiophene-Based Auxochromes Red-shift Chlorin Absorptions and Enable Oxidative Chlorin Polymerizations.
abstract: The de novo syntheses of chemically stable chlorins with five-membered heterocyclic (furane, thiophene, formylfurane and formylthiophene) substituents in selected meso- and β-positions are reported. Heterocycle incorporation in the 3- and 13-positions shifted the chlorin absorption and emission to the red (up to λem=680 nm), thus these readily incorporated substituents function analogously to auxochromes present in chlorophylls, for example, formyl and vinyl groups. Photophysical, theoretical and X-ray crystallographic experiments revealed small but significant differences between the behavior of the furan- and the thiophene-based auxochromes. Four regioisomeric bis-thienylchlorins (3,10; 3,13, 3,15 and 10,15) were oxidatively electropolymerized; the chlorin monomer geometry had a profound impact on the polymerization efficiency and the electrochemical properties of the resulting material. Chemical co-polymerization of 3,13-bis-thienylchlorin with 3-hexylthiophene yielded an organic-soluble red-emitting polymer.
authors.affiliation: Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, 75120, Uppsala, Sweden.
authors.forename: Ruisheng
authors.initials: R
authors.lastname: Xiong
authors.affiliation: Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, 75120, Uppsala, Sweden.
authors.forename: Anna-Bea
authors.initials: AB
authors.lastname: Bornhof
authors.affiliation: Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, 75120, Uppsala, Sweden.
authors.forename: Anna I
authors.initials: AI
authors.lastname: Arkhypchuk
authors.affiliation: Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, 75120, Uppsala, Sweden.
authors.forename: Andreas
authors.identifier: http://orcid.org/0000-0001-5403-9902
authors.initials: A
authors.lastname: Orthaber
authors.affiliation: Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, 75120, Uppsala, Sweden.
authors.forename: K Eszter
authors.identifier: http://orcid.org/0000-0003-2449-102X
authors.initials: KE
authors.lastname: Borbas
keywords: chlorins; electrochemistry; photophysics; polymerization; porphyrinoids