Stepwise neutral-ionic phase transitions in a covalently bonded donor/acceptor chain compound

Hitoshi Miyasaka, Natsuko Motokawa, Tamiko Chiyo, Miho Takemura, Masahiro Yamashita, Hajime Sagayama, Taka Hisa Arima

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58 Citations (Scopus)


Neutral (N)-ionic (I) transitions in organic donor (D)/acceptor (A) charge-transfer complexes are intriguing because a reservoir of functions is available. For systematically controlling N-I 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-I 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)] 2(p-xylene) (1; 2,3,5,6-F4PhCO2- = 2,3,5,6-tetrafluorobenzoate; DMDCNQI = 2,5-dimethyl-N,N′- dicyanoquinonediimine), where the [Ru2II,II(2,3,5,6-F 4PhCO2)4] moiety has a paddlewheel diruthenium(II,II) motif with a Ru-Ru 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-ground states as well as the ferrimagnetic ordering in the I phase vary. The stepwise feature of the N-I transition with a highly sensitive magnetic response should bring about new dynamical functionalities associated with charge, spin, and lattice.(Figure Presented)

Original languageEnglish
Pages (from-to)5338-5345
Number of pages8
JournalJournal of the American Chemical Society
Issue number14
Publication statusPublished - 2011 Apr 13

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


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