title: Pentacene appended to a TEMPO stable free radical: the effect of magnetic exchange coupling on photoexcited pentacene.
abstract: Understanding the fundamental spin dynamics of photoexcited pentacene derivatives is important in order to maximize their potential for optoelectronic applications. Herein, we report on the synthesis of two pentacene derivatives that are functionalized with the [(2,2,6,6-tetramethylpiperidin-1-yl)oxy] (TEMPO) stable free radical. The presence of TEMPO does not quench the pentacene singlet excited state, but does quench the photoexcited triplet excited state as a function of TEMPO-to-pentacene distance. Time-resolved electron paramagnetic resonance experiments confirm that triplet quenching is accompanied by electron spin polarization transfer from the pentacene excited state to the TEMPO doublet state in the weak coupling regime.
authors.affiliation: Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg , Henkestr. 42, 91054 Erlangen, Germany.
authors.forename: Erin T
authors.initials: ET
authors.lastname: Chernick
authors.forename: Rubén
authors.initials: R
authors.lastname: Casillas
authors.forename: Johannes
authors.initials: J
authors.lastname: Zirzlmeier
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Gardner
authors.forename: Marco
authors.initials: M
authors.lastname: Gruber
authors.forename: Henning
authors.initials: H
authors.lastname: Kropp
authors.forename: Karsten
authors.initials: K
authors.lastname: Meyer
authors.forename: Michael R
authors.initials: MR
authors.lastname: Wasielewski
authors.forename: Dirk M
authors.initials: DM
authors.lastname: Guldi
authors.forename: Rik R
authors.initials: RR
authors.lastname: Tykwinski
mesh_terms: D003497:Cyclic N-Oxides / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry; D060328:Magnetic Phenomena; D008958:Models, Molecular; D008968:Molecular Conformation; D009279:Naphthacenes / Q000138:chemical synthesis / Q000737:chemistry*; D055668:Photochemical Processes
chemical_list: D003497:Cyclic N-Oxides; D005609:Free Radicals; D009279:Naphthacenes; C523499:pentacene; C003959:TEMPO