摘要:
IntroductionRadical cation salts and charge transfer complexes based on tetrathiafulvalene (TTF) and its derivatives constitute a wide class of organic materials with transport properties ranging from insulating to superconducting.1The relative arrangement of the molecules in the solid state was found to be a crucial parameter in determining the properties of the target compound.2Investigations of organic/inorganic hybrid molecular materials combining conducting electrons and localized spins are of great interest.3–10When combining the two properties one of the aims is to obtain long-range magnetic coupling between isolated localized spins of the inorganic networks that contain transition metals (d-electrons)viathe mobile electrons within the organic networks (π-electrons). To satisfy this model, which is based onthe synergy between electrical conductivity and magnetic interactions, two conditions are needed, namely good electrical conductivity and strong interactions between the organic and inorganic networks. In order to establish magnetic and/or structural interactions between the organic and inorganic sublattices, several methods are under investigation. Recently, TTF-derived salts containing [Cr(NCS)4(L)n]−, L = 1,10-phenanthroline (phen) or isoquinoline (isoq), have been reported.10These salts were designed with the idea that magnetic interactions would be induced by both S⋯S contacts and π-stacking overlap between the paramagnetic anions and organic radicals. Indeed, a large number of the salts showed long-range ferrimagnetic order withTcvalues ranging from 4.2 to 8.9 K. Other work in this area is based on interactionsthrough –N⋯I– contacts11or covalent bonding between the conducting and the paramagnetic networks.12Continuing our efforts in this line, we report here the preparation, X-ray crystal structure, transport and magnetic properties of α-(BEDT-TTF)2[Feiii(phen)(NCS)4] (1) [BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene, phen = 1,10-phenanthroline] as well as the crystal structure of (BEDT-TTF)[Criii(isoq)2(NCS)4] (2) (isoq = isoquinoline) for which the physical properties have been reported previously for a microcrystalline sample.10
ISSN:1466-8033
DOI:10.1039/b110466g
出版商:RSC
年代:2001
数据来源: RSC