title: BODIPY functionalized o-carborane dyads for low-energy photosensitization.
abstract: A new type of organic dyad that can induce low-energy photosensitization has been developed; electron donor and electron acceptor units are boron dipyrromethene (BODIPY) and ortho-carborane (o-Cb), respectively. The new dyads consist of a V-shaped BODIPY-(o-Cb)-BODIPY molecular array in which two BODIPY units are substituted onto two adjacent carbon atoms of the central o-Cb. In the presence of the o-Cb unit, as an electron acceptor, significant fluorescence quenching was observed which indicated that photoinduced electron transfer (PET) had occurred from the end-on BODIPY units to the central o-Cb with PET efficiencies of 63-71%. As a result, the corresponding cationic and anionic species that are responsible for the charge transfer state were detected by the serial spectroelectrochemical studies: cationic BODIPY radicals at 400 nm at the applied voltage of 1.44 V and broad absorption bands of anionic o-Cb radicals in the range of 250-490 nm at -1.84 V. Transient absorption studies further confirmed the BODIPY radical anion at 540 nm and the o-Cb radical anion at 350-475 nm with a structureless broad band.
authors.affiliation: Department of Advanced Materials Chemistry, Korea University, Sejong 339-700, South Korea. dwcho@korea.ac.kr sangok@korea.ac.kr.
authors.forename: Guo Fan
authors.initials: GF
authors.lastname: Jin
authors.forename: Yang-Jin
authors.initials: YJ
authors.lastname: Cho
authors.forename: Kyung-Ryang
authors.initials: KR
authors.lastname: Wee
authors.forename: Seong Ahn
authors.initials: SA
authors.lastname: Hong
authors.forename: Il-Hwan
authors.initials: IH
authors.lastname: Suh
authors.forename: Ho-Jin
authors.initials: HJ
authors.lastname: Son
authors.forename: Jong-Dae
authors.initials: JD
authors.lastname: Lee
authors.forename: Won-Sik
authors.initials: WS
authors.lastname: Han
authors.forename: Dae Won
authors.initials: DW
authors.lastname: Cho
authors.forename: Sang Ook
authors.initials: SO
authors.lastname: Kang