Synthesis and Photochromism of Spirobenzopyrans and Spirobenzothiapyran Derivatives Bearing Monoazathiacrown Ethers and Noncyclic Analogues in the Presence of Metal Ions
作者:Mutsuo Tanaka、Tomokazu Ikeda、Qiang Xu、Hisanori Ando、Yasuhiko Shibutani、Makoto Nakamura、Hidefumi Sakamoto、Setsuko Yajima、Keiichi Kimura
DOI:10.1021/jo0162843
日期:2002.4.1
Spirobenzopyrans bearing monoazathiacrown ethers and noncyclic analogues were synthesized, and their ion-responsive photochromism depending on the dual metal ion interaction with the crown ether and the phenolate anion moieties was examined using alkali and alkaline-earth metal ions, Ag+, Tl+, Pb2+, Hg2+, and Zn2+. The prepared spirobenzopyrans showed a selective binding ability to Mg2+ and Ag+ with negative and positive photochromism, respectively. Among the metal ions, only Ag+ facilitated photoisomerization to the corresponding merocyanine form. Depending on the ring size of the monoazathiacrown ether moieties, soft metal ions such as Hg2+ and Ag+ showed significant shifts in the UV-vis absorption spectra, while hard metal ions such as Mg2+, Zn2+, and Pb2+ did not afford any meaningful shift. This result reflects that the monoazathiacrown ether and phenolate anion moieties prefer soft and hard metal ions, respectively. Therefore, the Mg2+ and Ag+ selectivities are mainly derived from the phenolate anion and monoazathiacrown ether moieties, respectively. On the other hand, a spirobenzothiapyran bearing 3,9-dithia-6-monoazaundecane showed a remarkable selectivity to Ag+.