title: Synthesis, photochemistry, and electrochemistry of single-wall carbon nanotubes with pendent pyridyl groups and of their metal complexes with zinc porphyrin. Comparison with pyridyl-bearing fullerenes.
abstract: A soluble, functionalized Py-SWNT has been synthesized and characterized by solution (1)H and (13)C NMR, FT-Raman, and electron microscopy. Experimental data indicate that Py-SWNT has short tubes with pentyl esters at the tips and pyridyl isoxazolino units along the walls. The synthesis of Py-SWNT is based on a 1,3-dipolar cycloaddition of a nitrile oxide on the SWNT walls, similar to 1,3-dipolar cycloadditions that are common for fullerene functionalization. The resulting Py-SWNT forms a complex with a zinc porphyrin (ZnPor) in a way similar to that reported for pyridyl-functionalized [60]-fullerenes. Formation of this metal-ligand complex was firmly established by a detailed electrochemical study. However, in contrast to the behavior observed for the ZnPor/Py-C(60) complex, photochemical excitation of the complex between ZnPor/Py-SWNT does not lead to electron transfer with the generation of charge-separated states. Fluorescence and laser flash studies indicate that the main process is energy transfer from the singlet ZnPor excited state to the Py-SWNT with observation of emission from Py-SWNT. Triplet ZnPor excited-state quenching by Py-SWNT is only observed in polar solvents such as DMF, but not in benzonitrile.
authors.affiliation: Instituto de Tecnología Química CSIC-UPV, Universidad Politécnica de Valencia, 46022-Valencia, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Alvaro
authors.forename: Pedro
authors.initials: P
authors.lastname: Atienzar
authors.forename: Pilar
authors.initials: P
authors.lastname: de la Cruz
authors.forename: Juan L
authors.initials: JL
authors.lastname: Delgado
authors.forename: Vincent
authors.initials: V
authors.lastname: Troiani
authors.forename: Hermenegildo
authors.initials: H
authors.lastname: Garcia
authors.forename: Fernando
authors.initials: F
authors.lastname: Langa
authors.forename: Amit
authors.initials: A
authors.lastname: Palkar
authors.forename: Luis
authors.initials: L
authors.lastname: Echegoyen