Coordination polymers based on diiron tetrakis(dithiolato) bridged by alkali metals, electrical bistability around room temperature, and strong antiferromagnetic coupling

Inorg Chem. 2015 Mar 2;54(5):2243-52. doi: 10.1021/ic502789v. Epub 2015 Feb 10.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electric Conductivity
  • Ferrous Compounds / chemistry*
  • Metals, Alkali / chemistry*
  • Models, Molecular
  • Polymers / chemistry*
  • Semiconductors
  • Sulfhydryl Compounds / chemistry*
  • Temperature*

Substances

  • Ferrous Compounds
  • Metals, Alkali
  • Polymers
  • Sulfhydryl Compounds