Syntheses, luminescence switching, and electrochemical studies of photochromic dithienyl-1,10-phenanthroline zinc(II) bis(thiolate) complexes

A series of zinc(II) diimine bis(thiolate) complexes with photochromic diarylethene-containing phenanthroline ligands was synthesized, and their photophysical and photochromic properties were studied. The X-ray crystal structures of two of these complexes have been characterized. All complexes exhibit strong 3LLCT phosphorescence at 510-620 nm in the solid state at 77 and 298 K and in EtOH-MeOH glass at 77 K. Detailed studies revealed that the absorption, emission, and electrochemical properties of the complexes could be readily switched via the photochromic ring-closing and ring-opening reactions.