Preparation, Structure and Physical Properties of BEDT-TTF* Nitrates

Abstract

Electrocrystallization of BEDT -TTF in THF with tetrabutylammonium nitrate as supporting electrolyte leads to the deposition of at least three different phases. The a-phase (C 10 H 8 S 8 ) 3 (NO 3 ) 2 , M t = 1277.98, crystallizes in the monoclinic space group P2 1 /n. The structure of this solid was solved: a = 5.890(2), b = 31.125(10), c = 12.915(6) Ä , β = 103.73(3)°, V = 2300 Å 3, Z - 2, D x = 1.84 gem -3 , MoKf α λ = 0.7107 Å , μ = 11.2 cm -1 , F(000) = 1300, room temperature, R = 0.057 for 1888 observed independent reflections. Sheets of BEDT-TTF radical cations with short intermolecular S···S contacts (>3.315(4) Å ) are separated by anion layers. Two more BEDT-TTF nitrates have been characterized by their unit cell data. Results of temperature dependent electrical conductivity and thermopower measurements on crystals of the a-phase are presented. They are metallic down to about 30 K