title: Hetero triply-bridged dinuclear copper(II) compounds with ferromagnetic coupling: a challenge for current density functionals.
abstract: Seven new hetero triply-bridged dinuclear Cu(II) compounds have been synthesized and characterized corresponding to a series with general formula [Cu(2)(L)(2)(μ-OH)(μ-OH(2))(μ-O(2)CR)]X(2) (where L = bpy = 2,2'-bipyridine, 4,4'-dmbpy = 4,4'-dimethyl-2,2'-bipyridine and 5,5'-dmbpy = 5,5'-dimethyl-2,2'-bipyridine; R = H for formate, CH(3) for acetate, CH(2)CH(3) for propionate and C(CH(3))(3) for trimethylacetate and X = CF(3)SO(3)(-) and ClO(4)(-)). All compounds exhibit ferromagnetic behavior with the experimental J values derived from magnetic susceptibility measurements being in the 73-104 cm(-1) range. The overall qualitative behavior is reproduced by state of the art density functional theory based methods. However, none of the functionals is able to reproduce the fine details along the series which constitutes an excellent benchmark for future developments.
authors.affiliation: Materials Chemistry Research Unit, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Nanthawat
authors.initials: N
authors.lastname: Wannarit
authors.forename: Chaveng
authors.initials: C
authors.lastname: Pakawatchai
authors.forename: Ilpo
authors.initials: I
authors.lastname: Mutikainen
authors.forename: Ramon
authors.initials: R
authors.lastname: Costa
authors.forename: Ibério de P R
authors.initials: Ide P
authors.lastname: Moreira
authors.forename: Sujittra
authors.initials: S
authors.lastname: Youngme
authors.forename: Francesc
authors.initials: F
authors.lastname: Illas