title: Donor-Acceptor-Donor Thienopyrazines via Pd-Catalyzed C-H Activation as NIR Fluorescent Materials.
abstract: A series of thienopyrazine-based donor-acceptor-donor (D-A-D) near-infrared (NIR) fluorescent compounds were synthesized through a rapid, palladium-catalyzed C-H activation route. The dyes were studied through computational analysis, electrochemical properties analysis, and characterization of their photophysical properties. Large Stokes shifts of approximately 175 nm were observed, which led to near-infrared emission. Computational evaluation shows that the origin of this large Stokes shift is a significant molecular reorganization particularly about the D-A bond. The series exhibits quantum yields of up to φ = >4%, with emission maxima ranging from 725 to 820 nm. The emission is strong in solution, in thin films, and also in isolation at the single-molecule level. Their stable emission at the single-molecule level makes these compounds good candidates for single-molecule photon sources in the near-infrared.
authors.affiliation: Department of Chemistry and Biochemistry, University of Mississippi , University, Mississippi 38677, United States.
authors.forename: Louis E
authors.initials: LE
authors.lastname: McNamara
authors.affiliation: Department of Chemistry and Biochemistry, University of Mississippi , University, Mississippi 38677, United States.
authors.forename: Nalaka
authors.initials: N
authors.lastname: Liyanage
authors.affiliation: Department of Chemistry and Biochemistry, University of Mississippi , University, Mississippi 38677, United States.
authors.forename: Adithya
authors.initials: A
authors.lastname: Peddapuram
authors.affiliation: Department of Chemistry and Biochemistry, University of Mississippi , University, Mississippi 38677, United States.
authors.forename: J Scott
authors.initials: JS
authors.lastname: Murphy
authors.affiliation: Department of Chemistry and Biochemistry, University of Mississippi , University, Mississippi 38677, United States.
authors.forename: Jared H
authors.initials: JH
authors.lastname: Delcamp
authors.affiliation: Department of Chemistry and Biochemistry, University of Mississippi , University, Mississippi 38677, United States.
authors.forename: Nathan I
authors.initials: NI
authors.lastname: Hammer
mesh_terms: D002384:Catalysis; D005456:Fluorescent Dyes / Q000737:chemistry*; D006860:Hydrogen Bonding; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D058924:Thienopyridines / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D058924:Thienopyridines; D010165:Palladium