Metallic Bi‐ and Monolayered Radical Cation Salts Based on Bis(ethylenedithio)­tetrathiafulvalene (BEDT‐TTF) with the Tris(oxalato)gallate Anion

Abstract

New metallic triclinic (1) and monoclinic (2) crystals of the (BEDT‐TTF)4AI[MIII(C2O4)3]G family of organic molecular conductors have been prepared: α‐“pseudo‐κ”‐(BEDT‐TTF)4Kx(H3O)1–x[GaIII(C2O4)3]·1,2‐C6H4Br2 (x ≈ 0.45) (1) and β″‐(BEDT‐TTF)4Kx(H3O)1–x[GaIII(C2O4)3]·PhBr (x ≈ 0.33) (2). The triclinic crystals belong to a quite rare type of bilayered radical ion salts and contain alternating BEDT‐TTF layers with two distinct packing motifs (α‐ and “pseudo‐κ”). The monoclinic crystals contain one kind of BEDT‐TTF radical cation layers. The crystal structure, transport, and magnetotransport properties of 1 and 2 have been studied. The Shubnikov–de Haas (SdH) oscillations were found in both phases. The structure and properties of 1 and 2 are compared with another similar phase with M = FeIII.

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

“…α-β" 12 or α-κ. 13 Changing the counter cation has also produced a variety of different phases such as (BEDT-TTF)4(H2O)LiFe(C2O4)3 9 from lithium, (BEDT-TTF)9Na18[Fe(C2O4)3]8·24H2O 14 from sodium, (BEDT-TTF)12[Fe(C2O4)3]2·nH2O 15 from caesium, and (BEDT-TTF)5[Fe(C2O4)3]·CH2Cl2·2H2O 16 from tetraethylammonium. Changing the charge on the metal from 3+ to 4+ using germanium produces very different phases: (BEDT-TTF)2[Ge(C2O4)3]•benzonitrile, 17 (BEDT-TTF)5[Ge(C2O4)3]2, 18 (BEDT-TTF)7[Ge(C2O4)3]2(CH2Cl2)0.87(H2O)0.09 18 and BEDT-TTF4[Ge(C2O4)3].0.5CH2Cl2.…”

In Search of Chiral Molecular Superconductors: κ‐[(S,S)‐DM‐BEDT‐TTF]2ClO4 Revisited

“…The CC and internal CS bond lengths values are rather similar for the four A-D donors (Table S2, Supporting Information) and do correspond to a mixed valence state. While very few BEDT-TTF salts containing two different alternating layer types such as α-κ [ 30 ] and α-"pseudo-κ" [31] have been described, those possessing two different κ layers are exceptionally rare and present potentially huge interest with respect to their electronic structures. As a matter of fact, to the best of our knowledge, there is only one reported example of such material and it concerns the κ-(BEDT-TTF) 4 PtCl 6 •C 6 H 5 CN salt which shows a very weakly activated conductivity down to 250 K where a first order phase transition takes place towards an insulating regime.…”

Effect of Halopyridine Guest Molecules on the Structure and Superconducting Prop­erties of β″‐[Bis(ethylenedithio)tetra­thiafulvalene]4(H3O)[Fe(C2O4)3]·Guest Crystals

“…[13,14,20] The orthorhombic group of the crystals contains some semiconductors (M III = Fe, Cr, Co, Al; A = K + , NH 4 + , H 3 O + ; G = PhCN and its mixtures with PhNO 2 or 1,2-C 6 H 4 Cl 2 ). These crystals grow in "dry" solvents and also together with monoclinic crystals in the presence of traces of water.…”

“…The largest group in this class of compounds is the family of BEDT-TTF salts with magnetic and nonmagnetic tris(oxalato)metallate anions (BEDT-TTF) 4 ; M = Fe, Cr, Mn, Ru, Ga, Al, Co; G = "guest" solvent). [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Crystals of this family possess a great diversity of conducting properties (from semiconducting to met-allic and superconducting). A distinguishing feature of this anionic subsystem is the honeycomb-like architecture of the two-dimensional anionic layers: the M III and A I cations linked by oxalate bridges alternate at vertexes of the hexagonal network and form the hexagonal cavities, which are able to incorporate neutral solvent molecules G.…”