Photochromic behavior of a bisthienylethene bearing Cu(I)-1,10-phenanthroline complexes

Abstract

A novel diarylethene having a 1,10-phenanthroline unit at each end of the molecule has been synthesized. Among the metal ions, it formed a stable complex with Cu(I) ions in acetonitrile. Rational structures of the Cu(I) complexes of the colorless and the photo-generated blue form have been given by PM3 semiempirical molecular orbital calculations to be 2:2 cyclic complexes for both isomers, with the complex of the open form belonging to the C 2 symmetry group while the complex of the closed form belongs to the D 2 symmetry group. Although the ring-closing quantum yield for free diarylethene in acetonitrile was 0.75, that for the complex was 0.026, due to the long distance of the bond-forming carbon atoms in the rigid (open form) 2-Cu(I) 2 complex.