Control of charge transfer phase transition and ferromagnetism by photoisomerization of spiropyran for an organic-inorganic hybrid system, (SP)[FeIIFeIlI(dto)3] (SP = spiropyran, dto = C2O2S2)

Noriyuki Kida*, Masanori Hikita, Izuru Kashima, Masashi Okubo, Miho Itoi, Masaya Enomoto, Kenichi Kato, Masaki Takata, Norimichi Kojima

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)

Abstract

Iron mixed-valence complex, (n-G3H7) 4N[FellFelll(dto)3](dto = C 2O2S2), shows a spin entropy- driven phase transition called charge transfer phase transition in [FellFe lll(dto)3]-∞ around 120 K and a ferromagnetic transition at 7 K. These phase transitions remarkably depend on the hexagonal ring size in the two-dimensional honeycomb network structure of [Fe lllllm(dto)3]-∞ In order to control the magnetic properties and the electronic state in the dto-bridged iron mixed-valence system by means of photoirradiation, we have synthesized a photosensitive organic-inorganic hybrid system, (SP)[FellFe lll(dto)3](SP = spiropyran), and investigated the photoinduced effect on the magnetic properties. Upon UV irradiation at 350 nm, a broad absorption band between 500 and 600 nm appears and continuously increases with the photoirradiation time, which implies that the UV irradiation changes the structure of spiropyran from the closed form to the open one in solid state. The photochromism in spiropyran changes the ferromagnetic transition temperature from 5 to 22 K and the coercive force from 1400 to 6000 Oe at 2 K. In this process, the concerted phenomenon coupled with the charge transfer phase transition in [FellFelll(dto)3]-∞ and the photoisomerization of spiropyran is realized.

Original languageEnglish
Pages (from-to)212-220
Number of pages9
JournalJournal of the American Chemical Society
Volume131
Issue number1
DOIs
Publication statusPublished - 2009 Jan 14
Externally publishedYes

ASJC Scopus subject areas

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

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