title: Tetrakis(4-pyridyl)porphyrin supramolecular complexes with cyclodextrins in aqueous solution.
abstract: The formation of inclusion complexes of hydroxypropyl-beta-cyclodextrin, heptakis(2,6-di-O-methyl)-beta-cyclodextrin and heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin with 5,10,15,20-tetrakis(4-pyridyl)porphyrin (TpyP) has been studied in aqueous buffer solution (phosphate buffer pH = 7 and I = 0.01 M) to give a structural and spectroscopic characterization of a new class of potential sensitizers for photodynamic therapy. The interaction was investigated by a combination of UV/Vis absorption, fluorescence anisotropy, time-resolved fluorescence and circular dichroism. The experimental results point to the presence of the pigment in water in a monomeric complexed form. The fluorescence anisotropy measurements suggest that TpyP forms 1:1 complexes with heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin, while 1:2 complexes are obtained with heptakis(2,6-di-O-methyl)-beta-cyclodextrin.
authors.affiliation: Dipartimento di Chimica, Università di Bari, Bari, Italy. p.cosma@chimica.uniba.it
authors.forename: Pinalysa
authors.initials: P
authors.lastname: Cosma
authors.forename: Lucia
authors.initials: L
authors.lastname: Catucci
authors.forename: Paola
authors.initials: P
authors.lastname: Fini
authors.forename: Pasquale L
authors.initials: PL
authors.lastname: Dentuto
authors.forename: Angela
authors.initials: A
authors.lastname: Agostiano
authors.forename: Nicola
authors.initials: N
authors.lastname: Angelini
authors.forename: Luigi Monsù
authors.initials: LM
authors.lastname: Scolaro