title: Synthesis and photophysical properties of fullerene-phthalocyanine-porphyrin triads and pentads.
abstract: The synthesis and photophysical properties of several fullerene-phthalocyanine-porphyrin triads (1-3) and pentads (4-6) are described. The three photoactive moieties were covalently connected in an one-step synthesis through 1,3-dipolar cycloaddition to C(60) of the corresponding azomethine ylides generated in situ by condensation reaction of a substituted N-porphyrinylmethylglycine derivative and an appropriated formyl phthalocyanine or a diformyl phthalocyanine derivative, respectively. ZnP-C(60)-ZnPc (3), (ZnP)(2)-ZnPc-(C(60))(2) (6), and (H(2)P)(2)-ZnPc-(C(60))(2) (5) give rise upon excitation of their ZnP or H(2)P components to a sequence of energy and charge-transfer reactions with, however, fundamentally different outcomes. With (ZnP)(2)-ZnPc-(C(60))(2) (6) the major pathway is an highly exothermic charge transfer to afford (ZnP)(ZnP(.+))-ZnPc-(C(60)(.-))(C(60)). The lower singlet excited state energy of H(2)P (i.e., ca. 0.2 eV) and likewise its more anodic oxidation (i.e., ca. 0.2 V) renders the direct charge transfer in (H(2)P)(2)-ZnPc-(C(60))(2) (5) not competitive. Instead, a transduction of singlet excited state energy prevails to form the ZnPc singlet excited state. This triggers then an intramolecular charge transfer reaction to form exclusively (H(2)P)(2)-ZnPc(.+)-(C(60)(.-))(C(60)). A similar sequence is found for ZnP-C(60)-ZnPc (3).
authors.affiliation: Departamento de Química e QOPNA, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Roger F
authors.initials: RF
authors.lastname: Enes
authors.forename: Juan-José
authors.initials: JJ
authors.lastname: Cid
authors.forename: Anita
authors.initials: A
authors.lastname: Hausmann
authors.forename: Olga
authors.initials: O
authors.lastname: Trukhina
authors.forename: Andreas
authors.initials: A
authors.lastname: Gouloumis
authors.forename: Purificación
authors.initials: P
authors.lastname: Vázquez
authors.forename: José A S
authors.initials: JA
authors.lastname: Cavaleiro
authors.forename: Augusto C
authors.initials: AC
authors.lastname: Tomé
authors.forename: Dirk M
authors.initials: DM
authors.lastname: Guldi
authors.forename: Tomás
authors.initials: T
authors.lastname: Torres