(Nitronyl Nitroxide)‐Substituted Trioxytriphenylamine Radical Cation Tetrachlorogallate Salt: A 2p‐Electron‐Based Weak Ferromagnet Composed of a Triplet Diradical Cation |
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| Authors: | Dr Masato Kuratsu Dr Shuichi Suzuki Dr Masatoshi Kozaki Dr Daisuke Shiomi Prof Kazunobu Sato Prof Takeji Takui Dr Tsuneki Kanzawa Prof Yuko Hosokoshi Dr Xiao‐Zheng Lan Dr Yuji Miyazaki Prof Akira Inaba Prof Keiji Okada |
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| Institution: | 1. Department of Chemistry, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi‐ku, Osaka 558‐8585 (Japan), Fax: (+81)?6‐6605‐2568;2. Department of Physical Science, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599‐8531 (Japan);3. Research Center for Structural Themodynamics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560‐0043 (Japan), Fax: (+81)?6‐6850‐5526 |
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| Abstract: | The synthesis and the solid state magnetic properties of (nitronyl nitroxide)‐substituted trioxytriphenylamine radical cation tetrachlorogallate, NNTOT+·GaCl4? , are reported. In the temperature region between 300 and 3 K, the magnetic behavior is characterized by the strong intramolecular ferromagnetic interaction (J/kB=+400 K) between the radical ( NN ) and the radical cation ( TOT +) and the weak intermolecular antiferromagnetic interaction (J/kB=?1.9 K) between NNTOT+ ions. Below 3 K, a 3D‐type long‐range magnetic ordering into a weak ferromagnet was observed (TN=2.65 K). The magnetic entropy (Smag=8.97 J K?1 mol?1) obtained by the heat capacity measurement is in good agreement with the theoretical value of R ln3=9.13 J K?1 mol?1 based on the S=1 state. |
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| Keywords: | cations heterocycles magnetic properties phase transitions radical ions |
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