Structural Study of the Thermally Induced and Photoinduced Phase Transitions of the 1,3,5-Trithia-2,4,6-triazapentalenyl (TTTA) Radical

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• 作者：Pan//pubs.acs.org/images/entities/ccaron.gif" border="0">e Naumov ; Jonathan P. Hill ; Kenji Sakurai ; Masahiko Tanaka ; Katsuhiko Ariga
• 刊名：Journal of Physical Chemistry A
• 出版年：2007
• 出版时间：July 19, 2007
• 年：2007
• 卷：111
• 期：28
• 页码：6449 - 6455
• 全文大小：231K
• 年卷期：v.111,no.28(July 19, 2007)
• ISSN：1520-5215

文摘

We report on the first direct atomic-level photodiffraction evidence for domain formation by doping withcharge photocarriers of the stable organic radical TTTA (1,3,5-trithia-2,4,6-triazapentalenyl), which exhibitsunusually wide thermal hysteresis of the paramagnetic-to-diamagnetic phase transition around ambienttemperature. A setup for steady-state powder photodiffraction was developed for the purpose, composed ofa second harmonic pulsed visible pump (532 nm) coupled with a powder diffractometer using monochromaticsynchrotron X-ray radiation as the probe. The refined structures of the photoinduced phase and the high-temperature phase are structurally identical. The result supports the model according to which photoexcitationcauses suppression of the spin-Peierls instability and separation of the radical dimers, resulting in a structurethat is essentially identical with the unperturbed high-temperature phase.