J. Phys. IV France
Volume 114, April 2004
Page(s) 561 - 563

J. Phys. IV France
114 (2004) 561
DOI: 10.1051/jp4:2004114133

Strong ${\pi }$-d interaction based on brominated TTF-type donor EDT-TTFBr 2

J. Nishijo1, 1, A. Miyazaki1, T. Enoki1, 1, R. Watanabe2, Y. Kuwatani2 and M. Iyoda2

1  Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8551, Japan
2  Department of Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan

New ${\pi }$ - d interacting system based on brominated TTF-type donor EDT-TTFBr 2 (= 4,5-dibromo-4 $^\prime $,5 $^\prime $ -ethylenedithiotetrathiafulvalene) was investigated. Magnetic (EDT-TTFBr 2)2FeBr 4 and non-magnetic (EDT-TTFBr 2)2GaBr 4 are isostructural salts, which have strong anion-donor interaction through Br-Br atomic contacts with weak direct anion-anion interaction. The iron salt takes an antiferromagnetic transition at TN = 11 K owing to strong ${\pi }$ - d interaction, which originates from the strong anion-donor interaction. The strong ${\pi }$ - d interaction also plays an important role in the electron transport phenomenon in the variation of temperature and applied magnetic field. Key words. ${\pi }$ - d interaction - negative magnetoresistance - organic magnetic conductor.

© EDP Sciences 2004