abstract
The charge transfer salt (DT-TTF)(4)[Au(pdS)(2)](3) (DT-TTF, A(2,2') -bithieno[3,4-d]-1,3-dithiol; pds, pyrazine-2,3-diselenate) was prepared and characterised by X-ray diffraction, electrical conductivity, thermoelectric power, magnetic susceptibility and EPR measurements. This compound crystallises in the triclinic system, space group P (1) over bar, with the unit cell parameters a = 9.712(5) Angstrom, b = 13.620(5) Angstrom, c = 17.169(5) Angstrom, alpha = 97.254(5)degrees, beta = 106.132(5)degrees, gamma = 95.956(5)degrees, V = 2141.10(15) Angstrom(3),Z = 1. Its crystal structure consists of a bidimensional network of DT-TTF tetramers and orthogonal anions. The electrical properties indicate it is a small gap semiconductor (2Delta = 190 meV), with a room temperature conductivity of sigma(RT) = 2 S cm(-1). The electrical and magnetic properties reveal two types of transitions occurring upon cooling. The first, at 238 K, as a second order change to a large gap semiconducting state and, a lower transition, of first order type, with a large hysteresis between 210 and 150 K, probably associated with a larger structural change in the DT-TTF network. (C) 2003 Elsevier Science Ltd. All rights reserved.
keywords
THERMOELECTRIC-POWER; DONORS
subject category
Chemistry; Crystallography
authors
Dias, JC; Morgado, J; Alves, H; Lopes, EB; Santos, IC; Duarte, MT; Henriques, RT; Almeida, M; Ribas, X; Rovira, C; Veciana, J
our authors
