title: High-spin ribbons and antiferromagnetic ordering of a Mn(II)-biradical-Mn(II) complex.
abstract: A binuclear metal coordination complex of the first thiazyl-based biradical ligand 1 is reported (1 = 4,6-bis(1,2,3,5-dithiadiazolyl)pyrimidine; hfac =1,1,1,5,5,5,-hexafluoroacetylacetonato-). The Mn(hfac)2-biradical-Mn(hfac)2 complex 2 is a rare example of a discrete, molecular species employing a neutral bridging biradical ligand. It is soluble in common organic solvents and can be easily sublimed as a crystalline solid. Complex 2 has a spin ground state of S(T) = 4 resulting from antiferromagnetic coupling between the S(birad) = 1 biradical bridging ligand and two S(Mn) = 5/2 Mn(II) ions. Electrostatic contacts between atoms with large spin density promote a ferromagnetic arrangement of the moments of neighboring complexes in ribbon-like arrays. Weak antiferromagnetic coupling between these high-spin ribbons stabilizes an ordered antiferromagnetic ground state below 4.5 K. This is an unusual example of magnetic ordering in a molecular metal-radical complex, wherein the electrostatic contacts that direct the crystal packing are also responsible for providing an efficient exchange coupling pathway between molecules.
authors.affiliation: Department of Chemistry, University of Guelph , Guelph, Ontario N1G 2W1, Canada.
authors.forename: Elisabeth M
authors.initials: EM
authors.lastname: Fatila
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Clérac
authors.forename: Mathieu
authors.initials: M
authors.lastname: Rouzières
authors.forename: Dmitriy V
authors.initials: DV
authors.lastname: Soldatov
authors.forename: Michael
authors.initials: M
authors.lastname: Jennings
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Preuss