Photochromism in Organic Crystals.

Photochromism of diarylethene molecules and crystals

Photochromism is defined as a reversible transformation of a chemical species between two isomers upon photoirradiation. Although vast numbers of photochromic molecules have been so far reported, photochromic molecules which exhibit thermally irreversible photochromic reactivity are limited to a few examples. The thermal irreversibility is an indispensable property for the application of photoc...

Photochromism of dithienylethene single crystals having anthracene substituents.

Three dithienylethene derivatives having anthracene substituents (connected at 1-, 2- and 9-positions) were prepared. Although these three derivatives exhibit photochromic reactivity in solution, only one of the derivatives (connected at 2-position) undergoes the photochromic reaction in the crystalline phase. X-Ray crystallographic analysis and DFT calculation revealed that conformation of the...

Excitons in Organic Molecular Crystals

Topotactic Reactions in Organic Crystals.

Crystalline organic compounds have been observed to react in a number of cases in a manner which suggests that the process is dependent on the geometry of the disposition of reactive groups in the crystal lattice. Such a process, first observed with inorganic reactions, has been designated by Kohlschuetter' as "topochemical," and several criteria may be used to show that a reaction falls into t...

Flexible ferroelectric organic crystals

Flexible organic materials possessing useful electrical properties, such as ferroelectricity, are of crucial importance in the engineering of electronic devices. Up until now, however, only ferroelectric polymers have intrinsically met this flexibility requirement, leaving small-molecule organic ferroelectrics with room for improvement. Since both flexibility and ferroelectricity are rare prope...