Synthesis and photochemical reactions of photochromic terarylene having a leaving methoxy group.

Photochromic terarylene having a methoxy group and hydrogen as the leaving units at the photochemical reaction center carbon atoms has been synthesized. This molecule shows irreversible photochemical reaction affording a highly fluorescent condensed aromatic molecule.

Photomodulation of ionic interaction and reactivity: reversible photoconversion between imidazolium and imidazolinium.

An interconversion system between imidazolium and imidazolinium has been proposed for the first time. Imidazolium and imidazolinium cations exhibit different reactivity due to the difference in the aromaticity and charge localization structure, which is successfully controlled by means of photoirradiation in the present system. A 4,5-dithiazolylimidazolium salt was prepared and studied as a new class of photochromic materials modulating electrostatic interactions and chemical reactivities.