Stepwise Neutral鈭扞onic Phase Transitions in a Covalently Bonded Donor/Acceptor Chain Compound

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• 作者：Hitoshi Miyasaka ; Natsuko Motokawa ; Tamiko Chiyo ; Miho Takemura ; Masahiro Yamashita ; Hajime Sagayama ; Taka-hisa Arima
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：April 13, 2011
• 年：2011
• 卷：133
• 期：14
• 页码：5338-5345
• 全文大小：1136K
• 年卷期：v.133,no.14(April 13, 2011)
• ISSN：1520-5126

文摘

Neutral (N)鈭抜onic (I) transitions in organic donor (D)/acceptor (A) charge-transfer complexes are intriguing because a 鈥榬eservoir of functions鈥?is available. For systematically controlling N鈭扞 transitions, tuning the ionization potential of D and the electron affinity of A is extremely important. However, the effect of Coulomb interactions, which likely causes a number of charge-gap states at once in a system bringing about stepwise transitions, is a long-standing mystery. Here, we show definite evidence for stepwise N鈭扞 transitions caused by contributions from anisotropic interchain Coulomb interactions in a metal-complex-based covalently bonded DA chain compound, [Ru₂(2,3,5,6-F₄PhCO₂)₄(DMDCNQI)]路2(p-xylene) (1; 2,3,5,6-F₄PhCO₂^{鈭?/sup> = 2,3,5,6-tetrafluorobenzoate; DMDCNQI = 2,5-dimethyl-N,N鈥?dicyanoquinonediimine), where the [Ru₂II,II(2,3,5,6-F₄PhCO₂)₄] moiety has a paddlewheel diruthenium(II,II) motif with a Ru鈭扲u bond. An intermediate-temperature phase involving self-organized N and I chains was observed in the temperature range between 210 K (= T₂) and 270 K (= T₁) with N phase at T > T₁ and I phase at T < T₂. Accompanying the charge transitions, the spin鈭抔round states as well as the ferrimagnetic ordering in the I phase vary. The stepwise feature of the N鈭扞 transition with a highly sensitive magnetic response should bring about new dynamical functionalities associated with charge, spin, and lattice.}