Res. Chem. Intermed.
, Vol. 30, No. 2, pp. 163– 179 (2004)
Also available online - www.vsppub.com
Fluorescence microscopy investigation on the manipulation
of guest species on zeolites
Chemistry Department and Advanced Engineering Courses, Gunma College of Technology,
Maebashi, Gunma 371-8530, Japan
Received 30 July 2003; accepted 3 October 2003
Abstract—We applied a uorescence microscopy method to investigate the possibility of molecular
manipulation such as intentional transfer of molecules from one zeolite crystal to another. Photo-
physical and photochemical processes of guest species incorporated in the zeolites were exploited as
indicator reactions in order to yield a luminescence color characteristic of individual zeolite particles.
Two types of migration mechanisms were observed: a through-space diffusional-transfer mode be-
tween separated zeolite crystals and a molecular injection process from a loaded crystal to another
unloaded crystal, both in contact. A preferential direction of guest migration was found to exist for a
few cases: for instance, aromatics such as phenanthreneand chrysene migrate from the sodium form of
zeolite X (Na
-X) to thallium-exchanged zeolite X (Tl
-X). On the other hand, the migration-assisted
formation of charge-transfer complexes between electron-donating arenes such as phenanthrene and
chrysene, and electron-accepting 1,2,4,5-tetracyanobenzene, both incorporated into separate zeolite
-X crystals, takes place as a result of the migration of the donors. The uorescence microscopy
method utilizing photochemistry in zeolites was found to be a powerful technique for the qualitative
investigation of the intercrystalline migration and possibly applicable to the observation of particle-
to-particle molecular manipulation processes.
: Photochemistry; zeolites; intercrystalline migration.
Precisely controlled manipulation of individual atoms and molecules using STM
and AFM tips is currently a target of research in nanoscience. While the basic
principles have been amply demonstrated, the slow access time and problems
associated with reliable, repeatable positioning with the probe instruments are
the hurdles to overcome . When turning our eyes to slightly larger-scale ma-
terials such as zeolite crystals, we may possibly manipulate directly micrometer-