title: New dinuclear nickel(II) and iron(II) complexes with a macrocyclic ligand containing a N6S2 donor-set: synthesis, structural, MALDI-TOF-MS, magnetic and spectroscopic studies.
abstract: A series of dinuclear Ni(II) and Fe(II) complexes with a Py(2)N(4)S(2) coordinating octadentate macrocyclic ligand L prepared by direct reactions have been studied. The overall geometry and bonding mode have been deduced on the basis of elemental analysis data, infrared, MALDI-TOF-MS, UV-vis spectroscopy, X-ray diffraction, conductivity and magnetic susceptibility measurements. In general both M(2+) centres are sited into the macrocyclic cavity coordinated to a pyridinic nitrogen atom, one sulfur atom, two secondary amine groups from the macrocyclic backbone and completing the coordination spheres with two solvent or anionic molecules in a distorted octahedral geometry, except in the case of [Ni(2)L(mu-Cl)(H(2)O)(2)](BF(4))(3).2H(2)O, where the metal ions are sited in the macrocyclic cavity coordinated to a pyridinic nitrogen atom, one sulfur atom, two secondary amine groups from the macrocyclic backbone, one water molecule and one chloride ion acting as a bridge between the two centres in a distorted octahedral geometry. The magnetic properties of the nickel(II) complexes, [Ni(2)L(CH(3)CN)(4)](BF(4))(4).3.5CH(3)CN (11) and [Ni(2)L(mu-Cl)(H(2)O)(2)](BF(4))(3).2H(2)O (12) has been recorded in the solid state and indicates an unexpected ferromagnetic exchange in both cases, especially in compound 11 because no similar systems are previously reported in the literature presenting this magnetic behaviour. Further complexes with similar ligands are in progress to corroborate this unexpected ferromagnetic behaviour.
authors.affiliation: Inorganic Chemistry Department, Faculty of Chemistry, University of Santiago de Compostela, 15782, Santiago de Compostela, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Núñez
authors.forename: Rufina
authors.initials: R
authors.lastname: Bastida
authors.forename: Alejandro
authors.initials: A
authors.lastname: Macías
authors.forename: Laura
authors.initials: L
authors.lastname: Valencia
authors.forename: Joan
authors.initials: J
authors.lastname: Ribas
authors.forename: José Luis
authors.initials: JL
authors.lastname: Capelo
authors.forename: Carlos
authors.initials: C
authors.lastname: Lodeiro
mesh_terms: D000588:Amines / Q000737:chemistry; D055598:Chemical Phenomena; D018360:Crystallography, X-Ray; D005296:Ferrous Compounds / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008024:Ligands; D008280:Magnetics; D008670:Metals / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013055:Spectrophotometry, Infrared; D013057:Spectrum Analysis; D014961:X-Ray Diffraction
chemical_list: D000588:Amines; D005296:Ferrous Compounds; D008024:Ligands; D008670:Metals; D009942:Organometallic Compounds; D011725:Pyridines; D009532:Nickel; D007501:Iron