Res. Chem. Intermed.
, Vol. 33, No. 1–2, pp. 143–153 (2007)
Also available online - www.brill.nl/rci
Preparation and photochromism of diarylethene covalently
bonded onto layered sodium-magadiite surfaces
, HIROSHI HANAKI
, RYO SASAI
, TATSUTO YUI
and KATSUHIKO TAKAGI
Department of Crystalline Materials Science, Graduate School of Engineering Nagoya University,
Furo-cho, Chikusa-ku, 464-8603, Japan
Research Center for Advanced Emission Management (ResCWE), Nagoya University, Chikusa-ku,
Nagoya 464-8603, Japan
Japan Science and Technology Agency (JST), Tokyo, Japan
Received 9 January 2004; accepted 9 May 2004
Abstract—Diarylethene derivatives (DE) covalently bonded to silanol oxygens of layered silicate
surfaces, i.e., magadiite (Mag), were synthesized and investigated for their photochromic behavior.
The DE-Mag layered hybrids were found to undergo reversible color change by alternating UV and
visible light irradiation. A more highly efﬁcient, reproducible photochromic behavior was realized
with DE-Mag than with a corresponding DE-Si possessing silyl substituents on DE in place of the
Mag surface. Moreover, the present covalently bonded DE exhibited an improvement over DE hybrids
incorporated in layered double hydroxide (LDH) clays, in which the repetitive photochromic behavior
decreased during alternating irradiation, due to the accumulation of the photochemically inert parallel
isomers of DE.
Keywords: Diarylethene; magadiite; layered inorganic material; photochromism.
Diarylethene derivatives (DE) are thermally stable and yet highly efﬁcient in their
photochemical interconvertibility with their closed-ring isomers, as outlined in
Scheme 1 . They are, therefore, expected to be one of the most promising
materials for applications in memory devices. However, the development of
thermally stable materials that can maintain efﬁcient, high-repetition photochromic
properties, even in the solid state, is required.
Clays are alumino-silicate minerals of layered structure which have the potential
to accommodate various molecules within their interlayer spaces [2–4], enabling
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