Development of Molecule-based Functional Material
Yoshiaki Nakano, Molecular Materials Science Laboratory
He was born in 1977. He graduated from Department of Industrial Chemistry, Faculty ofEngineering, Kyoto University in 2000 and received his Doctor of Engineering from Kyoto
University in 2005 for a thesis entitled “Studies on Electronic Properties of Organic Multi-SpinSystems”. He was a postdoctoral fellow in Research Center for Low Temperature and Materials
Sciences (Apr., 2005 - Jun., 2008), and Institute for Integrated Cell-Material Sciences (Jul., 2008 Mar., 2009), Kyoto University. From Apr., 2009, he has been an Assistant Professor in ResearchCenter for Low Temperature and Materials Sciences, and then an assistant professor in theDivision of Chemistry, Graduate School of Science, Kyoto University.

(1) Anion size and isotope effects in (EDO-TTF)2XF6: (EDO-TTF)2PF6 undergoes the peculiar

metal-insulator transition and the ultra-fast and highly efficient
XOS
S
photo-induced insulator-to-metal phase transition. The deuterated
salts, (EDO-TTF-d2)2XF6 (X = P, As), showed the higher transition
SSOYtemperatures (TMI’s) by 2~3 K than the undeuterated salts. The TMIEDO-TTF: X = Y = H
and the width of thermal hysteresis (ΔTMI) of (EDO-TTF)2XF6 (X = P, EDO-TTF-d : X = Y = D2As, Sb) systematically changed depending on the anion, i.e., the TMI MeEDO-TTF: X = CH , Y = H
3decreased and the ΔTMI increased with increasing the anion size (PF6< AsF6 < SbF6).

(2) Room temperature phase transition in (MeEDO-TTF)2PF6: The black plate modificationof (MeEDO-TTF)2PF6 exhibited the semiconductor-to-semiconductor first-order phase transition ataround room temperature. One donor molecule was crystallographically unique in both the high- andlow-temperature (HT and LT) phases, the HT phase of which is isostructural to the metallic(MeEDO-TTF)2X (X = BF4, ClO4). The vibrational spectroscopy, which is a higher time-resolution
measurement than X-ray diffraction, proved that the nearly localized charge disproportionation takes
place in the HT phase and the distinct charge disproportionation evolved in the LT phase.
(3) Structures and physical property of radical cation salts of TP-EDTT: (TP-EDTT)2SbF6,(TP-EDTT)3(PF6)2, (TP-EDTT)GaCl4, and (TP-EDTT)ReO4 were prepared.
Based on the bond lengths, it was suggested that three kinds of differently
charged molecules coexisted in the PF6 salt. In the semiconducting SbF6 salt, nosign of charge disproportionation was found in the range from 300 to 6 K toassign this salt as a dimer Mott insulator.

(4)

Chargedisproportionationin

θ-(BTM-TTP)2SbF6:

semiconducting behavior, while the band calculation affords the closed
Fermi surface characteristic of 2D metal. In order to clarify the origin ofthe carrier localization, Raman spectroscopy was applied to reveal thatthe charge disproportionation occurs from room temperature and thefluctuation of charge is suppressed with decreasing temperature.

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TP-EDTT

θ-(BTM-TTP)2SbF6shows

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BTM-TTPPublications
1. Isotope effect on metal–insulator transition of (EDO-TTF)2XF6 (X = P, As) with multi-instability ofmetallic state, Y. Nakano, K. Balodis, H. Yamochi, G. Saito, M. Uruichi, K. Yakushi, Solid State Sci.,
10(12), 1780-1785 (2008)
2. Room-Temperature First-Order Phase Transition in a Charge-Disproportionated Molecular Conductor(MeEDO-TTF)2PF6, X.F. Shao, Y. Nakano, M. Sakata, H. Yamochi, Y. Yoshida, M. Maesato, M.
Uruichi, K. Yakushi, T. Murata, A. Otsuka, G. Saito, S. Koshihara, K. Tanaka, Chem. Mater., 20(24),7551-7562 (2008)-1-3. Anion size and isotope effects in (EDO-TTF)2XF6, Y. Nakano, H. Yamochi, G. Saito, M. Uruichi, K.
Yakushi, J. Phys.: Conf. Ser., 148, 012007/1-4 (2009)
4. Charge ordering state of mixed-valence (TP-EDTT)3(PF6)2, Y. Nakano, M. Takahashi, M. Sakata, H.
Yamochi, G. Saito, K. Tanaka, Synth. Met., 159(21-22), 2381-2383 (2009)
5. Synthesis, crystal structure, and physical property of radical cation salt of
2-(thiopyran-4-ylidene)-4,5-ethylenedithio-1,3-dithiole (TP-EDTT): (TP-EDTT)2SbF6, Y. Nakano, T.
Nishi, M. Uruichi, K. Yakushi, H. Yamochi, Physica B, 405(11S), S49-S54 (2010)
6. Charge disproportionation in a semiconducting θ-type salt of BTM-TTP, Y. Nakano, Y. Misaki, M.
Uruichi, K. Yakushi, H. Yamochi, Physica B, 405(11S), S198-S201 (2010)-2-