title: A dinuclear cobalt(II) complex of calix[8]arenes exibiting strong magnetic anisotropy.
abstract: The solvothermal reaction of cobalt(II) acetate with p-tert-butylcalix[8]arene (calix) and triethylamine affords the compound (Et3NH)2 [CoII2(calix)2] (.2Et3NH) that shows a hydrogen bond bridged dinuclear complex [CoII2(calix)2]2- () with cobalt(II) ions in a tetrahedral geometry. The compound crystallises in the monoclinic, space group P2(1)/n with cell parameters a=14.89(1) A, b=20.90(2) A, c=30.87(4) A, beta=102.57(7) degrees, V=9376(16) A3, Z=2. The magnetic studies together with ab initio calculations are evidence of an important role of the geometry of the second coordination sphere of carbon and hydrogen atoms around the CoO4 core in quantifying the zero field splitting on cobalt sites. This results in strong magnetic anisotropies with a negative axial component on the cobalt fragments.
authors.affiliation: Université Claude Bernard Lyon-1, Laboratoire des Multimatériaux et Interfaces (UMR 5615), Campus de La Doua, 69622, Villeurbanne Cedex, France.
authors.forename: Sarah
authors.initials: S
authors.lastname: Petit
authors.forename: Guillaume
authors.initials: G
authors.lastname: Pilet
authors.forename: Dominique
authors.initials: D
authors.lastname: Luneau
authors.forename: Liviu F
authors.initials: LF
authors.lastname: Chibotaru
authors.forename: Liviu
authors.initials: L
authors.lastname: Ungur