title: Mono-, di-, and oligonuclear complexes of Cu(II) ions and p-hydroquinone ligands: syntheses, electrochemical properties, and magnetic behavior.
abstract: Four highly soluble square-planar Cu(II) and Ni(II) complexes of siloxy-salens (2SiCu, 2SiNi) and hydroxy-salens (2Cu, 2Ni) have been synthesized. An X-ray crystal structure analysis was performed on 2SiCu, 2SiNi, and 2Ni. The compounds have been investigated by cyclic voltammetry, UV-vis-NIR spectroelectrochemistry, and EPR spectroscopy. According to these results, the monooxidized species [2SiCu]+ and [2SiNi]+ are to be classified as Robin-Day class II and III systems, respectively. Magnetic measurements on the dinuclear (PMDTA)Cu(II) complex 1Cu2 x (PF6)2 with deprotonated 1,4-dihydroxy-2,5-bis(pyrazol-1-yl)-benzene (1) linker revealed antiferromagnetic coupling between the two Cu(II) ions thereby resulting in an isolated dimer compound. Coordination polymers [1Cu]n(H2O)(2n) of Cu(II) ions and bridging p-hydroquinone linkers were obtained from CuSO4 x 5 H2O and 1,4-dihydroxy-2,5-bis(pyrazol-1-yl)benzene. X-ray crystallography revealed linear chains running along the crystallographic a-direction and stacked along the b-axis. Within these chains, the Cu(II) ions are coordinated by two pyrazolyl nitrogen atoms and two p-hydroquinone oxygen atoms in a square-planar fashion.
authors.affiliation: Institut für Anorganische Chemie and Institut für Organische Chemie, J.W. Goethe-Universität Frankfurt, Marie-Curie-Strasse 11, D-60439 Frankfurt (Main), Germany.
authors.forename: Günter
authors.initials: G
authors.lastname: Margraf
authors.forename: Tonia
authors.initials: T
authors.lastname: Kretz
authors.forename: Fabrizia
authors.initials: F
authors.lastname: Fabrizi de Biani
authors.forename: Franco
authors.initials: F
authors.lastname: Laschi
authors.forename: Serena
authors.initials: S
authors.lastname: Losi
authors.forename: Piero
authors.initials: P
authors.lastname: Zanello
authors.forename: Jan W
authors.initials: JW
authors.lastname: Bats
authors.forename: Bernd
authors.initials: B
authors.lastname: Wolf
authors.forename: Katarina
authors.initials: K
authors.lastname: Remović-Langer
authors.forename: Michael
authors.initials: M
authors.lastname: Lang
authors.forename: Andrei
authors.initials: A
authors.lastname: Prokofiev
authors.forename: Wolf
authors.initials: W
authors.lastname: Assmus
authors.forename: Hans-Wolfram
authors.initials: HW
authors.lastname: Lerner
authors.forename: Matthias
authors.initials: M
authors.lastname: Wagner
mesh_terms: D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D006873:Hydroquinones / Q000737:chemistry*; D008024:Ligands; D008280:Magnetics; D008958:Models, Molecular; D008968:Molecular Conformation; D009532:Nickel / Q000737:chemistry; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D012680:Sensitivity and Specificity; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
chemical_list: D006873:Hydroquinones; D008024:Ligands; D009942:Organometallic Compounds; D003300:Copper; D009532:Nickel; C031927:hydroquinone