Packing along b axis
ET[Au(dcdmp)2]
STRUCTURAL AND ELECTRICAL TRANSPORT PROPERTIES OF MOLECULAR CONDUCTORS BASED ON [AU(DCDMP)2] MONOANION
D. Belo1; V. Gama1; S. Rabaça1; I.C. Santos1 ; M.T. Duarte2; E.B. Lopes1; M. Almeida1
1 Instituto Tecnológico e Nuclear,
P-2686 Sacavém (Portugal)
2 Instituto Superior Técnico, P-1096
Lisboa (Portugal), E-mail: dbelo@itn1.itn.pt
Keywords: molecular conductor, Crystal structure,
dithiolates
A new gold-dithiolate complex was synthesised and charge transfer salts with TTF, TMTSF and ET were obtained both by slow diffusion and by electrocrystallisation. Electrical conductivity at room temperature show values between 102 and 10-4 Scm-1 , depending on the donor molecule. The lowest conductivity was observed for ET[Au(dcdmp)2], 7x10-4 Scm-1 with an activation energy of 206 mev, while for the TTF complex an electric conductivity of 192 Scm-1 was observed.
The ET[Au(dcdmp)2] complex crystallises in the monoclinic space group P21/c with a=16.230(4) A, b=7.557(2) A, c=24.655(9) A, b =100.41(2)o. The complex forms 1:1 alternate donor acceptor mixed stacks along the b axis. Au-S , S-S and N-S interactions are observed either between the donor - donor and the acceptor-donor. Although mixed stark 1D compounds usually are insulators, in this case the S - S intra-chain contacts allow electronic (3D) delocalization and lead to electronic conductivity.
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Packing along b axis |
ET[Au(dcdmp)2] |
The TTF[Au(dcdmp)2] complex crystallises on the monoclinic space group C2/m, with a=15.638(5) A, b=15.65(7) A, c=3.57(1) A, b =90.70(5)o, and the crystal structure is under resolution. Crystal structure determination of the recently obtained TMTSF[Au(dcdmp)2] is now being done, the value of the electric conductivity at room temperature being 8.0 Scm-1.
This work is included in a wide study for obtaining and developing molecular metals and molecular superconductors. ,;