title: Tritopic phenanthroline and pyridine tail-tied aza-scorpiands.
abstract: The synthesis of two new tritopic double-scorpiand receptors in which two equivalent 5-(2-aminoethyl)-2,5,8-triaza[9]-(2,6)-pyridinophane moieties have been linked with 2,6-dimethylpyridine (L1) or 2,9-dimethylphenanthroline (L2) units is reported for the first time. Their acid-base behaviour and Zn(2+) coordination chemistry have been studied by pH-metric titrations, molecular dynamic calculations, NMR, UV-Vis and steady-state fluorescence techniques. L1 and L2 behave, respectively, as hexaprotic and heptaprotic bases in the experimental conditions used (298.1 +/- 0.1 K, 0.15 mol dm(-3) NaCl, pH range under study 2.0-11.0). These ligands are able to form mono-, bi- and trinuclear Zn(2+) complexes depending on the Zn(2+)-receptor molar ratio. Interaction of L1 and L2 with pyrophosphate (PPi), tripolyphosphate (TPP) and adenosine 5'-triphosphate (ATP) has been followed by pH-metric titrations, (1)H and (31)P NMR techniques and molecular dynamic analysis. Finally, formation of mixed complexes Zn(2+)-L-PPi, Zn(2+)-L-TPP and Zn(2+)-L-ATP has been studied for both receptors by potentiometric titrations.
authors.affiliation: Instituto de Ciencia Molecular (ICMOL), Departamento de Química Inorgánica, Universidad de Valencia, Edificio de Institutos de Paterna, Apartado de Correos 22085, 46071, Valencia, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: González
authors.forename: José M
authors.initials: JM
authors.lastname: Llinares
authors.forename: Raquel
authors.initials: R
authors.lastname: Belda
authors.forename: Javier
authors.initials: J
authors.lastname: Pitarch
authors.forename: Concepción
authors.initials: C
authors.lastname: Soriano
authors.forename: Roberto
authors.initials: R
authors.lastname: Tejero
authors.forename: Begoña
authors.initials: B
authors.lastname: Verdejo
authors.forename: Enrique
authors.initials: E
authors.lastname: García-España