title: Coordination polymers based on diiron tetrakis(dithiolato) bridged by alkali metals, electrical bistability around room temperature, and strong antiferromagnetic coupling.
abstract: Coordination polymer chains have been formed by the direct reaction between HSC6H2Cl2SH and FeCl3·6H2O in the presence of an aqueous solution of the corresponding alkali-metal hydroxide (M = Li, Na, and K) or carbonate (M = Rb and Cs). The structures consist of dimeric [Fe2(SC6H2Cl2S)4](2-) entities bridged by [M2(THF)4] [M = K (1), Rb (2), and Cs (3); THF = tetrahydrofuran] or {[Na2(μ-H2O)2(THF)2] (5 and 5') units. The smaller size of the lithium atom yields an anion/cation ion-pair molecule, [Li(THF)4]2[Fe2(SC6H2Cl2S)4] (4), in which the dianionic moieties are held together by Cl···Cl interactions. Electrical characterization of these compounds shows a general semiconductor behavior in which the conductivity and activation energies are mainly determined by the M-Cl and M-S bond distances. Compounds 1 and 5' are interesting examples of bistability showing reversible transitions centered at ca. 350 and 290 K with very large hysteresis of ca. 60 and 35 K, respectively. All of these compounds exhibit intradimer strong antiferromagnetic Fe···Fe interactions.
authors: Instituto de Ciencia Molecular, Universidad de Valencia , C/Catedrático José Beltrán 2, 46980 Paterna, Valencia, Spain.
authors: Samia
authors: S
authors: Benmansour
authors: Esther
authors: E
authors: Delgado
authors: Carlos J
authors: CJ
authors: Gómez-García
authors: Diego
authors: D
authors: Hernández
authors: Elisa
authors: E
authors: Hernández
authors: Avelino
authors: A
authors: Martin
authors: Josefina
authors: J
authors: Perles
authors: Félix
authors: F
authors: Zamora
mesh_terms: D004553:Electric Conductivity; D005296:Ferrous Compounds / Q000737:chemistry*; D008672:Metals, Alkali / Q000737:chemistry*; D008958:Models, Molecular; D011108:Polymers / Q000737:chemistry*; D012666:Semiconductors; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013696:Temperature
chemical_list: D005296:Ferrous Compounds; D008672:Metals, Alkali; D011108:Polymers; D013438:Sulfhydryl Compounds