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Free keywords:
Structure; Organic Metals; Superconductors
Abstract:
Crystals of the β-phases of (BEDT-TTF)2Br-I-Br (1) and (BEDT-TTF)2I-I - Br (2) have been isolated by electrocrystallization. The solids can be obtained using different tetrabutylammonium trihalides containing iodine and bromine as supporting electrolytes. Cyclovoltam metric results show clearly that the trihalide anions are involved in the oxidation reactions near the anode which finally lead to the crystals.
1 C20H16Br2IS16, Mr = 1056.01, and 2 C20H16BrI2S16, Mt = 1103.01 are isom orphous, crystallizing in the triclinic space group P1̄, with Z = 1. Unit cell parameters for 1: a = 6.5979(6) A , b = 8.998(1) Å, c = 15.138(3) Å , a = 94.03(1)°, β = 95.13(1), γ = 110.28(1), V = 834.7 Å and for 2: α = 6.606(2) Å , b = 9.047(6) A , c = 15.229(6) Å, α = 94.28(2)°, β = 95.34(2), v = 109.92(2), V = 846.5 Å3.
The different sizes of the Br2I- and Brl2- counterions lead to different intra- and interstack S -S contacts in the solids thus influencing the physical properties. An additional Br2I- phase with a modulation of the above-described structure could be found. Some relevant physical properties of 1 and 2 are reported.
