-O-dodecyl tripeptide bromides formed a parallel -sheet structure when they aggregated in water and in CCl 4 . The parallel -sheet was distinguished from the antiparallel counterpart by Fourier transform infrared spectroscopy because the former lacks a weak band at about 1690 cm -1 that is characteristic for the latter. The FT-IR spectra of the aggregate in CCl 4 remained unchanged if the solution was diluted to 0.01 mM, condensed to dryness, or heated to 60°C, and hence, the -sheet was easily formed and thermodynamically stable. The parallel -sheet was also possible to transform into an antiparallel -sheet, for example, by mixing with another tripeptide-containing amphiphile whose tripeptide part had an opposite direction. Transmission electron microscope (TEM) and atomic force microscope (AFM) pictures revealed that the aggregate in CCl 4 is a bundle of small filaments whose diameters are 70-80 Å. Developed interpeptide hydrogen bonding should be formed along the long axis of the filament. The morphological structures and stable peptide arrangements of the present assemblages are similar to those of the amyloid fiber whose accumulation causes fatal diseases.

The direct and reversible transformation of matter between the solid and liquid phases by light at constant temperature is of great interest because of its potential applications in various manufacturing settings. We report a simple molecular design strategy for the phase transitions: azobenzenes having para-dialkoxy groups with a methyl group at the meta-position. The photolithography processes were demonstrated using the azobenzene as a photoresist in a single process combining development and etching of a copper substrate.

When a fluorescent compound shows unique optical properties, an elucidation of the mechanism may lead to an important development of novel sensing strategies. A helical 3,3′-di-tert-butylsalen-zinc(II) complex, [Zn 2 L 1 2 ], has a red-shifted fluorescence as compared to that of [ZnL 2 2 ], a half-structured mononuclear complex of [Zn 2 L 1 2 ]; in addition, [Zn 2 L 1 2 ] exhibits a fluorescence color change from green to light blue under external stimulations. We investigated the origins of these phenomena by spectroscopy, fluorescence lifetime measurement, fluorescence microscopy, X-ray powder diffraction, and X-ray singlecrystal analysis. From the experimental data, we concluded that intramolecular and intermolecular π-π interactions are critical elements that determine the shifts of the fluorescence to a longer wavelength.