2D Molecular Superconductor to Insulator Transition in the β''-(BEDT-TTF)[(HO)(NH)M(CO)]·18-crown-6 Series (M = Rh, Cr, Ru, Ir).

The series of salts β''-(BEDT-TTF)[(HO)(NH)M(CO)]·18-crown-6 show ambient-pressure superconductivity when M = Cr, Rh. Evidence indicates that the previously reported Cr and Rh salts show a bulk Berezinski-Kosterlitz-Thouless superconducting transition. The isostructural ruthenium and iridium salts are reported here.

Bulk Kosterlitz-Thouless Type Molecular Superconductor β″-(BEDT-TTF)[(HO)(NH)Cr(CO)]·18-crown-6.

A new molecular superconductor, β″-(BEDT-TTF)[(HO)(NH)Cr(CO)]·18-crown-6, has been synthesized from the organic donor molecule BEDT-TTF with the anion Cr(CO). The crystal structure consists of conducting organic layers of BEDT-TTF molecules which adopt the β″ packing motif (layer A), layers of NH and Λ-Cr(CO) (layer B), layers of (HO)(NH)18-crown-6 (layer C), and layers of NH and Δ-Cr(CO) (layer D) which produce a superstructure with a repeating pattern of ABCDABCDA. As a result of this packing arrangement, this is the 2D superconductor with the widest gap between conducting layers where only a single donor packing motif is present (β″).

Molecular conductors from bis(ethylenedithio)tetrathiafulvalene with tris(oxalato)rhodate.

This article reports a family of new radical-cation salts of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) with tris(oxalato)rhodate: three salts with the formula β''-(BEDT-TTF)[(cation)Rh(CO)]·solvent (solvent = fluorobenzene, chlorobenzene, or bromobenzene) and one with the formula pseudo-κ-(BEDT-TTF)[(NH)Rh(CO)]·benzonitrile. We report here the syntheses, crystal structures, electrical properties and Raman spectroscopy of these new molecular conductors. The bromobenzene salt shows a decrease in resistivity below 2.

Ambient-pressure molecular superconductor with a superlattice containing layers of tris(oxalato)rhodate enantiomers and 18-crown-6.

We report a novel multilayered organic-inorganic hybrid material, β″-(BEDT-TTF)[(HO)(NH)Rh(CO)]·18-crown-6. This is the first molecular superconductor to have a superlattice with layers of both BEDT-TTF and 18-crown-6 and also the first with the anion tris(oxalato)rhodate. This is the 2D superconductor with the widest gap between conducting layers, where only a single donor packing motif is observed (β″).

Enantiopure and racemic radical-cation salts of B(malate)2(-) anions with BEDT-TTF.

We have synthesized the first examples of radical-cation salts of BEDT-TTF with chiral borate anions, [B(malate)2](-), prepared from either enantiopure or racemic bidentate malate ligands. In the former case only one of two diastereoisomers of the borate anion is incorporated, while for the hydrated racemic salt one racemic pair of borate anions containing a R and a S malate ligand is incorporated. Their conducting and magnetic properties are reported.