title: Homo- and heteronuclear compounds with a symmetrical bis-hydrazone ligand: synthesis, structural studies, and luminescent properties.
abstract: Nine new coordination compounds have been synthesized by the reaction of salts of bivalent metal ions (a=Zn(II) , b=Cu(II) , c=Ni(II) , d=Co(II) ) with the bis(benzoylhydrazone) derivative of 4,6-diacetylresorcinol (H4 L). Three kinds of complexes have been obtained: homodinuclear compounds [M2 (H2 L)2 ]⋅nH2 O (1 a, 1 b, 1 c, and 1 d), homotetranuclear compounds [M4 (L)2 ]⋅n(solv) (2 a and 2 c), and heterotetranuclear compounds [Zn2 M2 (L)2 ]⋅n(solv) (2 ab, 2 ac, and 2 ad). The structures of the free ligand H4 L⋅2 DMSO and its complexes [Zn2 (H2 L)2 (DMSO)2 ] (1 a*), [Zn4 (L)2 (DMSO)6 ] (2 a*), and [Zn0.45 Cu3.55 (L)2 (DMSO)6 ]⋅2 DMSO (2 ab*) were elucidated by single-crystal X-ray diffraction. The ligand shows luminescence properties and its fluorimetric behavior towards M(II) metals (M=Zn, Cu, Ni and Co) has been studied. Furthermore, the solid-state luminescence properties of the ligand and compounds have been determined at room temperature. (1) H NMR spectroscopic monitoring of the reaction of H4 L with Zn(II) showed the deprotonation sequence of the OH/NH groups upon metal coordination. Heteronuclear reactions have also been monitored by using ESI-MS and spectrofluorimetric techniques.
authors.affiliation: Instituto de Investigación Biomédica, Universidade de Vigo, Departamento de Química Inorgánica, Facultade de Química, 36310 Vigo, Galicia (Spain); Current address: ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona (Spain).
authors.forename: Sabina
authors.initials: S
authors.lastname: Rodríguez-Hermida
authors.forename: Ana B
authors.initials: AB
authors.lastname: Lago
authors.forename: Rosa
authors.initials: R
authors.lastname: Carballo
authors.forename: Oscar
authors.initials: O
authors.lastname: Fabelo
authors.forename: Ezequiel M
authors.initials: EM
authors.lastname: Vázquez-López
keywords: copper; hydrazones; luminescence; nickel; zinc