Premium
Ambient‐Pressure Organic Superconductors κ‐(DMEDO‐TSeF) 2 [Au(CN) 4 ](solv.): T c Tuning by Modification of the Solvent of Crystallization
Author(s) -
Shirahata Takashi,
Kibune Megumi,
Yoshino Hiroko,
Imakubo Tatsuro
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200700314
Subject(s) - orthorhombic crystal system , crystallography , crystallization , chemistry , monoclinic crystal system , solvent , superconductivity , phase (matter) , crystal structure , stereochemistry , physics , organic chemistry , condensed matter physics
The unsymmetrical π donor dimethyl(ethylenedioxy)tetraselenafulvalene (DMEDO‐TSeF) has provided six new organic superconductors with a monovalent square‐planar [Au(CN) 4 ] − ion and cyclic ethers as solvent of crystallization. The six new organic superconductors κ‐(DMEDO‐TSeF) 2 [Au(CN) 4 ](solv.) [solv.=1,3‐dioxolane (DOL), 2,5‐dihydrofuran (DHF), tetrahydropyran (THP), 1,3‐dioxane (1,3‐DOX), 3,4‐dihydro‐2 H ‐pyran (DHP), or 1,4‐dioxane (1,4‐DOX)] are classified into two subphases κ L and κ′ according to the differences in their space group symmetry. κ L ‐(DMEDO‐TSeF) 2 [Au(CN) 4 ](solv.) (solv.=DOL, DHF, THP, 1,3‐DOX or DHP) crystallizes in the orthorhombic space group Pnma , and T c of the κ L phase varies by 1.7–5.3 K according to the size and shape of the solvent of crystallization. On the other hand, κ′‐(DMEDO‐TSeF) 2 [Au(CN) 4 ](solv.) (solv.=DOL or 1,4‐DOX) crystallizes in the noncentrosymmetric monoclinic space group Cc . The κ′‐phase containing 1,4‐DOX shows superconductivity at 4.2 K, but the κ′‐phase containing DOL does not show superconductivity down to 1.4 K. Systematic investigation of the six new organic superconductors, together with the two previously reported superconductors κ H ‐ and κ L ‐(DMEDO‐TSeF) 2 [Au(CN) 4 ](THF), revealed that the T c of the present system is finely tunable by utilizing the effect of the solvent of crystallization.