title: Cu(2+), Zn(2+), and Ni(2+) Complexes of C2-Symmetric Pseudopeptides with an Aromatic Central Spacer.
abstract: Two new tetradentate C2-symmetric pseudopeptidic ligands derived from Val and Phe containing two amino and two amido groups and a central o-substituted aromatic spacer have been prepared. Their complexes with Cu(2+), Zn(2+), and Ni(2+) have been studied by potentiometry, UV-vis spectrophotometry, FT-IR, and ESI-MS. The presence of the aromatic spacer provides Cu(2+) complexes with stability constants several orders of magnitude higher than those observed for related ligands containing aliphatic central spacers. Besides, the formation of [MH-2L] complex species is favored. Crystal structures for the corresponding Cu(2+) and Ni(2+) have been obtained, revealing the metal atom in an essentially square-planar geometry, although, in several instances, the oxygen atom of an amide carbonyl of a second complex species can act as a fifth coordination site. In the case of Zn(2+), the only crystal structure obtained displays a square-pyramidal arrangement of the metal center. Finally, preliminary experiments show the catalytic activity of some of these complexes, in particular, Zn(2+) complexes, for epoxide ring-opening with using aniline as the nucleophile in a ligand accelerated process.
authors.affiliation: Departamento de Química Inorgánica y Orgánica, Universitat Jaume I , Av. de Vicent Sos Baynat, s/n, 12071, Castellón, Spain.
authors.forename: Lingaraju
authors.initials: L
authors.lastname: Gorla
authors.affiliation: Departamento de Química Inorgánica y Orgánica, Universitat Jaume I , Av. de Vicent Sos Baynat, s/n, 12071, Castellón, Spain.
authors.forename: Vicente
authors.initials: V
authors.lastname: Martí-Centelles
authors.affiliation: Departamento de Química Inorgánica y Orgánica, Universitat Jaume I , Av. de Vicent Sos Baynat, s/n, 12071, Castellón, Spain.
authors.forename: Lena
authors.initials: L
authors.lastname: Freimuth
authors.affiliation: Departamento de Química Inorgánica y Orgánica, Universitat Jaume I , Av. de Vicent Sos Baynat, s/n, 12071, Castellón, Spain.
authors.forename: Belén
authors.initials: B
authors.lastname: Altava
authors.affiliation: Departamento de Química Inorgánica y Orgánica, Universitat Jaume I , Av. de Vicent Sos Baynat, s/n, 12071, Castellón, Spain.
authors.forename: M Isabel
authors.initials: MI
authors.lastname: Burguete
authors.affiliation: Departamento de Química Inorgánica y Orgánica, Universitat Jaume I , Av. de Vicent Sos Baynat, s/n, 12071, Castellón, Spain.
authors.forename: Santiago V
authors.initials: SV
authors.lastname: Luis