title: Metal complexes with a new N(4)O(3) amine pendant-armed macrocyclic ligand: synthesis, characterization, crystal structures, and fluorescence studies.
abstract: The synthesis of a new oxaaza macrocyclic ligand, L, derived from O(1),O(7)-bis(2-formylphenyl)-1,4,7-trioxaheptane and tren containing an amine terminal pendant arm, and its metal complexation with alkaline earth (M = Ca(2+), Sr(2+), Ba(2+)), transition (M = Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+)), post-transition (M = Pb(2+)), and Y(3+) and lanthanide (M = La(3+), Er(3+)) metal ions are reported. Crystal structures of [H(2)L](ClO(4))(2).3H(2)O, [PbL](ClO(4))(2), and [ZnLCl](ClO(4)).H(2)O are also reported. In the [PbL] complex, the metal ion is located inside the macrocyclic cavity coordinated by all N(4)O(3) donor atoms while, in the [ZnLCl] complex, the metal ion is encapsulated only by the nitrogen atoms present in the ligand. pi-pi interactions in the [H(2)L](ClO(4))(2).3H(2)O and [PbL](ClO(4))(2) structures are observed. Protonation and Zn(2+), Cd(2+), and Cu(2+) complexation were studied by means of potentiometric, UV-vis, and fluorescent emission measurements. The 10-fold fluorescence emission increase observed in the pH range 7-9 in the presence of Zn(2+) leads to L as a good sensor for this biological metal in water solution.
authors.affiliation: Departamento de Química Inorgánica, Facultade de Química, Universidade de Santiago de Compostela, Avda das Ciencias s/n, E-15782 Santiago de Compostela, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Vicente
authors.forename: Rufina
authors.initials: R
authors.lastname: Bastida
authors.forename: Carlos
authors.initials: C
authors.lastname: Lodeiro
authors.forename: Alejandro
authors.initials: A
authors.lastname: Macías
authors.forename: A Jorge
authors.initials: AJ
authors.lastname: Parola
authors.forename: Laura
authors.initials: L
authors.lastname: Valencia
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Spey