J. Phys. IV France 114 (2004) 425
DOI: 10.1051/jp4:2004114101

Molecular materials with conducting and magnetic properties based on ET and [ M(tdas) ₂]^x- dithiolenes

M.L. Mercuri^{1, 1}, S. Curreli^{1, 2}, P. Deplano¹, L. Pilia¹, A. Serpe¹, E.F. Trogu¹, J.A. Schlueter^{3, 2} and C.J. Gómez-García<sup>2

1</sup>  Dipartimento di Chimica Inorganica ed Analitica, S.S. 554, Bivio per Sestu, 09042 Monserrato (Cagliari) Italy
²  Instituto de Ciencia Molecular, Universidad de Valencia, Dr. Moliner 50, 46100 Burjasot, Spain
³  Materials Science Division, Argonne National Laboratory, 60439-4831 Argonne, IL, USA

Abstract
Two hybrid molecular materials showing a combination of magnetic and conducting properties, the charge-transfer (ET) ₂[ Fe(tdas) ₂] (1) and (ET)Ni(tdas) ₂ (2), (ET=bis(ethylenedithio) tetrathiafulvalene; M=Fe, Ni; tdas=1,2,5-thiadiazole-3,4-dithiolate) salts, are characterized by vibrational (IR and Raman) and UV-VIS-NIR spectroscopies. These studies have proved to be effective and diagnostic tools in identifying the oxidation state (partial or integer) and the packing pattern (dimers or segregated stacks) of the ET donor only, since no (C=C) group vibration sensitive to the charge of M(tdas) ₂ complexes has been observed. This is ascribed to the extensive electron-delocalization inside the tdas ring in agreement with semiempirical extended Huckel calculations, indicating also that the AO's of the terminal S-atom give a high contribution to the HOMO and favour the occurrence of three-dimensional intermolecular interactions along the molecular longitudinal axis. These findings are consistent with structural results. Key words. Dithiolenes - Molecular Materials - Raman Spectroscopy - Reflectance Spectroscopy.

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