A turn on! A lockable photodriven molecular shuttle is based on a [2]rotaxane that consists of an α‐cyclodextrin threaded by a stilbene derivative. The fluorescent signals originate from the naphthalimide stopper and indicate the position of the shuttle. Once unlocked, the device can be turned on by irradiation at 335 nm and turned off by irradiation at 280 nm. The shuttle can be locked or unlocked by the addition acid or alkali, respectively (see picture).

An axially substituted subphthalocyanine (SubPc) was used as a selective chemodosimeter by the coordination of fluoride ion to the boron center. The UV-vis and fluorescence spectroscopic properties of the dosimetric system were studied. The results indicate that the SubPc is a sensitive and selective colorimetric and fluorescent dosimeter to fluoride ions.

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Substitution at the 4-position of 1,8-naphthalimide with electron-donating groups can increase fluorescent quantum yields and change emissive wavelengths from blue to red. Based on this molecular design concept, novel naphthalimide derivatives containing Schiff base moiety were prepared by condensing 4-hydrazino-1,8-naphthalimides with the aldehydes. Amino conjugation between the 4-amino-1,8-naphthalimide and the substituted moiety resulted in red shift of the absorption and fluorescence maximum wavelengths in the acetonitrile solution and in the net solid film. In the meantime, concentration-quenching effect of fluorescence for common luminescent materials was avoided. Some of these dyes emit brilliant red fluorescence in solid films and were used as non-doping emissive materials to fabricate electroluminescence devices. Based on these results, guidelines for the molecular design of non-doping red emissive materials for OLED applications are presented in this paper.

Hin und her: Ein [2]Rotaxan aus einem α‐Cyclodextrin und einem Stilbenderivat bildet ein verriegelbares molekulares Shuttle. Die Position des Shuttle wird durch den fluoreszierenden Naphthalimid‐Stopper angezeigt. Im entriegelten Zustand wird das Shuttle durch Bestrahlung bei 335 nm verschoben (zur Rückkehr dient Bestrahlung bei 280 nm). Verriegelt und entriegelt wird das Shuttle durch Zugabe von Säure bzw. Base (siehe Bild).