J. Am. Chem. Soc., 128 (29), 9292 -9293, 2006. 10.1021/ja062143c S0002-7863(06)02143-3
Web Release Date: July 4, 2006

Copyright © 2006 American Chemical Society

Negatively Charged -(C60-)2 Dimer with Biradical State at Room Temperature

Dmitri V. Konarev,* Salavat S. Khasanov, Akihiro Otsuka, Gunzi Saito,* and Rimma N. Lyubovskaya

Division of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan, Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow region 142432, Russia, Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow region, 142432, Russia, and Research Center for Low Temperature and Materials Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan

konarev@icp.ac.ru; saito@kuchem.kyoto-u.ac.jp

Received April 6, 2006

Abstract:

A negatively charged -(C60-)2 dimer bonded by two single bonds was found in the ionic multicomponent complex {(MDABCO+)·CoIITMPP}2·(C60-)2·(C6H4Cl2)2.5·(C6H5CN)1.5 (1). In contrast to the previously described diamagnetic -(C60-)2 dimer, the negatively charged -dimer has a biradical state at room temperature: (C60-)2 (S = 1). The behavior of spins in this dimer can be described by a model with a singlet ground state (S = 0) and a close lying excited triplet (S = 1) state with the energy gap of 2JAF = 70 ± 2 cm-1. On the whole, complex 1 shows a strong antiferromagnetic interaction of spins with a Weiss constant of -34 K.

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