title: Photochemical charge separation in closely positioned donor-boron dipyrrin-fullerene triads.
abstract: A series of molecular triads, composed of closely positioned boron dipyrrin-fullerene units, covalently linked to either an electron donor (donor(1)-acceptor(1)-acceptor(2)-type triads) or an energy donor (antenna-donor(1)-acceptor(1)-type triads) was synthesized and photoinduced energy/electron transfer leading to stabilization of the charge-separated state was demonstrated by using femtosecond and nanosecond transient spectroscopic techniques. The structures of the newly synthesized triads were visualized by DFT calculations, whereas the energies of the excited states were determined from spectral and electrochemical studies. In the case of the antenna-donor(1)-acceptor(1)-type triads, excitation of the antenna moiety results in efficient energy transfer to the boron dipyrrin entity. The singlet-excited boron dipyrrin thus generated, undergoes subsequent energy and electron transfer to fullerene to produce a boron dipyrrin radical cation and a fullerene radical anion as charge-separated species. Stabilization of the charge-separated state in these molecular triads was observed to some extent.
authors.affiliation: Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, KS 67260-0051, USA.
authors.forename: Channa A
authors.initials: CA
authors.lastname: Wijesinghe
authors.forename: Mohamed E
authors.initials: ME
authors.lastname: El-Khouly
authors.forename: Navaneetha K
authors.initials: NK
authors.lastname: Subbaiyan
authors.forename: Mustafa
authors.initials: M
authors.lastname: Supur
authors.forename: Melvin E
authors.initials: ME
authors.lastname: Zandler
authors.forename: Kei
authors.initials: K
authors.lastname: Ohkubo
authors.forename: Shunichi
authors.initials: S
authors.lastname: Fukuzumi
authors.forename: Francis
authors.initials: F
authors.lastname: D'Souza
mesh_terms: D001895:Boron / Q000737:chemistry*; D055664:Electrochemical Techniques; D004579:Electron Transport; D004735:Energy Transfer; D037741:Fullerenes / Q000737:chemistry*; D010084:Oxidation-Reduction; D011789:Quantum Theory; D013053:Spectrophotometry
chemical_list: D037741:Fullerenes; D001895:Boron