XII Iberian Meeting of Electrochemistry XVI Meeting of the ...

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XII Iberian Meeting of Electrochemistry & XVI Meeting of the Portuguese Electrochemical Society PE 15 Electrocrystallization of (D T-T T F) 2 [M(mnt) 2 ] on microelectrodes Rafaela A. L. Silva, 1 Mónica Afonso, 1 Manuel Matos 2,3 , Dulce Belo, 1 Manuel Almeida 1 1 Dept. Chemistry, ITN / CFMCUL Estrada Nacional 10, P-2686-953 Sacavém, Portugal 2 IT, Av. Rovisco Pais, P-1049-001 Lisboa, Portugal, 3 ISEL, Av. Emídio Navarro, P-1959-007 Lisboa, Portugal rafaela@itn.pt The charge transfer salts based on the organic donor dithiotetrathiafulvalene (DT-TTF) and transition metal bis-maleonitrile-dithiolate M(mnt) 2 with M =Au, Ni, Cu, Pt and Pd, are members of a general family of compounds with formula (DT-TTF) 2 [M(mnt) 2 ] presenting strongly paired stacks of partially oxidized donor molecules (DT-TTF) + 2 [1]. The compounds of this family with diamagnetic anions (M=Cu, Au) have attracted special interest because they were the first examples of organic spin ladder systems [2,3]. The study of these materials requires both high quality large single crystals and techniques able to characterize the electronic properties in rather small samples. Crystals of these compounds can be obtained by electrocrystallization conditions typical for charge transfer salts; the DT-TTF donor in a organic solvent is electrochemically oxidized in the presence of [M(mnt) 2 ] - anions to form the compound as crystals growing on the anode. In order to obtain large single crystals of high quality we have performed a study aimed at to optimize the electrocrystallization conditions. Using dichloromethane solutions and Pt as electrodes we were able to obtain good single crystals as large as 5x1x0.1 mm 3 . In order to make possible the measurement of electrical transport properties in smaller crystals of these compounds it was developed a technique of electrocrystallization on micropatterned electrodes. This technique using pulsed currents was able to provide small crystals directly connected to microelectrodes which can be used directly to electrical measurements. Acknowledgments: Work supported by F CT under contract PTDC/QUI-QUI/101788/2008. References [1] Ribera, E.; Rovira, C.; Veciana, J.; Tarrés, J.; Canadell, E.; Rousseau, R.; Molins, E.; Mas, M.; Schoefel, J-P.; Pouget, J.-P.; Morgado, J.; Henriques, R. T.; Almeida, M.; Chemistry an European Journal, 1999, 5, (7) 2025-2039. [2] Rovira, C.; Veciana, J.; Ribera, E.; Tarrés, J.; Canadell, E.; Rousseau, R.; Mas, M.; Molins, E.; Almeida, M.; Henriques, R. T.; Morgado, J.; Schoefel, J-P.; Pouget, J.-P.; Angewandte Chemie, International Edition in English, 1997, 36, 2324-2326. [3] Ribas, X.; Mas-Torrent, M.; Pérez-Benítez, A.; Dias, J. C.; Alves, H.; Lopes, E. B.; Henriques, R. T.; Molins, E.; Santos, I. C.; Wurst, K.; Foury-Leylekian, P.; Almeida, M.; Veciana, J.; Rovira, C.; Organic spin-Advanced Functional Materials, 2005, 15, 1023- 1035. September, 811, 2010. ISEL - Lisbon 106
XII Iberian Meeting of Electrochemistry & XVI Meeting of the Portuguese Electrochemical Society PE 16 An electrochemical study of Schiff-base oxovanadium(I V) complexes F . Bishehsari, A. Rouhollahi, S. Rayati #4, No.72, Sartip Fakoori Ave., Kargar Shomali Str., Tehran, Iran Faranak.bsh@gmail.com The interest in coordination chemistry of vanadium has increased because of its catalytic and medicinal importance [1-2]. The electrochemical behavior of three newly synthesized Schiff base VO(IV) complexes with electron donating groups were investigated, in acetonitrile (An) in the presence of tetrabutylammonium perchlorate as supporting electrolyte at the surface of GC electrode by cyclic voltammetry and chronopotentiometry (Figure 1). For all the VO(IV) compounds, one reversible oxidation wave has been found and the diffusion coefficients (D) were obtained. The effect of scan rate was evaluated. R = Me, X = H, Y = OMe Figure 1 - Cyclic voltammogram for [VOR 1 ] = 2.0010 -6 mol cm -3 at different sweep rates (0.01, 0.05, 01, 0.2 Vs -1 ) References [1] Butler, A.; Clague, M. J.; Meister, G. E. Chem. Rev, 1994, 94, 62 [2] Crans, D. C. J. Inorg. Biochem, 2000, 80, 123. September, 811, 2010. ISEL - Lisbon 107
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