Reversible Light-Driven Structural Changes between the Mono- and Bilayer Stacking Alignments in 4-Octadecyloxystilbazolium Arylcarboxylate Films

Abstract

The present investigation deals with the light-driven morphological changes in multilamella films of N-methyl-4-octadecyloxystilbazolium arylcarboxylates (C18OStz+X-) cast on glass slides. The results of XRD analysis show a photostimulated layer expansion and shrinkage of the stacked thin films along the c-axis under alternative illumination at >350 and 254 nm, respectively. It was revealed that such lamellar changes could be switched either way by a reversible transformation between the mono- and bilayer units in these stacked multilamella films. Moreover, such controlled structural adjustments in the alignment could be initiated by the photocyclodimerization of the stilbazolium moieties of the arylcarboxylate salts; i.e., a monolayer-to-bilayer transformation could be induced at a stage of only 10% cyclodimer formation. The photoinduced patterning on the surface of the films was also analyzed by SEM and fluorescence microscopic investigations.

Photochemical Reaction, Acidichromism, and Supramolecular Nanoarchitectures in the Langmuir−Blodgett Films of an Amphiphilic Styrylquinoxaline Derivative

“…The SQC16 was obtained as a yellow crystal: mp 176.5-177.0 °C. 1 H NMR (CDCl3), δ, ppm: 0.87 (t, 3H), 1.25-1.56 (m, 28H, (CH2)14); 4.0 (t, J ) 6.53 Hz, 2H, -OCH2); 6.9 (d, J ) 8. Chloroform was distilled before use.…”

“…FT-IR spectra were recorded using a JASCO FT-IR 660 spectrometer. 1 H NMR spectra were recorded on a dm × 300 (Bruker) instrument. Elemental analysis was performed on a Carlo-Erba-1106 instrument.…”

Cyanines Bearing Quaternary Azaaromatic Moieties

“…58 Reversible light-driven morphological changes in multilamellar films of 24 cast on glass plates have been observed. 60 Controlled structural changes in the alignment begin with the photocyclodimerization of the stilbazolium moieties of aryl carboxylate salts. The syn-HH …”

Preparation of Poly(silylene-p-phenylene)s Containing a Pendant Fluorophor and Their Applications to PL Imaging

“…In general, however, it may be difficult to avoid phase separation as well as aggregation of the fluorophores in the matrixes during preparation, operation, or storage of the films, which cause a significant decrease of the PL efficiencies. Although applications of stilbene-type fluorophores, whose photolysis leads to nonemissive [2 + 2] dimers, to PL imaging have been also reported, these must be used in forms of well-aligned LB films …”

“…Although applications of stilbene-type fluorophores, whose photolysis leads to nonemissive [2 + 2] dimers, to PL imaging have been also reported, these must be used in forms of well-aligned LB films. 3 Recently, we demonstrated that nucleophilic substitution of poly(ethoxysilylenephenylene)s provides a convenient approach to variously substituted poly-(silylenephenylene)s. 4 In these reactions, highly electrophilic properties of the EtO-Si bond originate the smooth substitution on the polymers. 5 In the hope of obtaining single component and simply accessible PL imaging materials, we prepared poly(silylene-p-phenylene)s bearing an anthrylethynyl, pyrenylethynyl, or terthienyl group as the pendant by substitution reactions of poly[ethoxy(methyl)silylene-p-phenylene] with the corresponding organolithium reagents.…”