Different Photochromic Rates of Azopyridine Derivatives in New Dual Photoisomeric Cobaloxime Complex Crystals

作者：Yamagiwa Hiroki; Sekine Akiko^*

来源：Bulletin of the Chemical Society of Japan, 2013, 86(9): 1028-1034.

DOI：10.1246/bcsj.20130136

Two cobaloxime complexes, namely (3-cyanopropyl)(3-phenylazopyridine)cobaloxime and (3-cyanopropyl)(4-phenylazopyridine)cobaloxime, were synthesized as new dual photoisomeric complexes for controlling the reactivity of trans-cis photoisomerization of phenylazopyridine derivatives in the solid state. The phenylazopyridine moieties of the crystals were transformed from the trans to the cis-form on exposure to UV light. In contrast, the 3-cyanopropyl groups of the crystals were isomerized to 1-cyanopropyl groups on irradiation with visible light. Moreover, the 3-1 photoisomerization of the 3-cyanopropyl group occurred with retention of the single-crystal form. The rates of the trans-cis transformations of the phenylazopyridine moieties of the crystals before the 3-1 phototransformation were compared with those after the phototransformation in the solid state. For the two crystals, the rates of the trans-cis phototransformations significantly increased after 3-1 photoisomerization. The crystal structures before and after 3-1 photoisomerization were analyzed. The free space around the phenylazopyridine moieties expanded as a result of 3-1 photoisomerization. It is clear that the reaction rates of the trans-cis transformations of the phenylazopyridine moieties on exposure to UV light can be modified by introducing another photoreactive group that is photoisomerized by visible light.

• 出版日期2013-9-15