The synthesis and photochromic properties of two bis(phosphine) ligands based on dithienylethene backbone and their oxides, sulfurets and selenides

A phosphor atom was introduced into photochromic dithienylethene and the corresponding dithienylethene bis(phosphine)ligands were obtained by the lithiation of 1,2-bis-(5-chloro-2-methylthien-3-yl) cyclopentene in the presence of n-butyllithium which were then reacted with Ph2PCl or Cy2PCl, respectively. The bis(phosphine)ligands were oxidised with H2O2, sulfurated by S8 and selenated by Se and their structures were characterized.