title: Hydrogen and copper ion-induced molecular reorganizations in scorpionand-like ligands. A potentiometric, mechanistic, and solid-state study.
abstract: Two aza scorpionand-like macrocycles (L2 and L3) have been prepared. L2 consists of a tren amine with two of its arms cyclizized with a 2,6-bis(bromomethyl)pyridine. In L3, the remaining pendant arm has been further functionalized with a fluorophoric naphthalene group. X-ray data on the compounds [H(L3)]ClO4.H2O (1) and [H3(L3)](H2PO4)3.H2O (2) as well as solution studies (pH-metry, UV-vis, and fluorescence data) show the movement of the pendant arm as a result of the protonation degree of the macrocycles and of the formation of intramolecular hydrogen bonds. X-ray data on the complexes [Cu(L2)](ClO4)2]2.H2O (3) and [Cu(L3)](ClO4)2 (4) and solution studies on Cu2+ coordination show the implication of the nitrogen of the arm in the binding to the metal ion. Kinetic studies on the decomposition and formation of the Cu2+ complexes provide additional information about the pH-dependent molecular reorganizations. Moreover, the obtained information suggests that the kinetics of the tail on/off process is essentially independent of the lability of the metal center.
authors.affiliation: Departamento de Química Inorgánica, Instituto de Ciencia Molecular, Universidad de Valencia, Edificio de Institutos de Paterna, Apdo 22085, 46071 Valencia, Spain.
authors.forename: Begoña
authors.initials: B
authors.lastname: Verdejo
authors.forename: Armando
authors.initials: A
authors.lastname: Ferrer
authors.forename: Salvador
authors.initials: S
authors.lastname: Blasco
authors.forename: Carmen Esther
authors.initials: CE
authors.lastname: Castillo
authors.forename: Jorge
authors.initials: J
authors.lastname: González
authors.forename: Julio
authors.initials: J
authors.lastname: Latorre
authors.forename: M Angeles
authors.initials: MA
authors.lastname: Máñez
authors.forename: Manuel García
authors.initials: MG
authors.lastname: Basallote
authors.forename: Conxa
authors.initials: C
authors.lastname: Soriano
authors.forename: Enrique
authors.initials: E
authors.lastname: García-España
mesh_terms: D003300:Copper / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000737:chemistry*; D007700:Kinetics; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D017976:Phosphorus Acids / Q000737:chemistry; D011199:Potentiometry; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D007477:Ions; D008024:Ligands; D017976:Phosphorus Acids; D014867:Water; D003300:Copper; D006859:Hydrogen