Synthesis and preliminary physical properties of new neutral tetraalkoxy-substituted nickel bis(1,2-dithiolene) complexes

Nineteen neutral nickel bisdiphenylethenedithiolene complexes [Ni(dpedt)2], including seventeen new compounds, were synthesized and characterized by a new short, efficient and multigram-scale synthetic method. Preliminary physical investigations show that these complexes are electron-withdrawing materials exhibiting good thermal stability and high molecular absorption coefficient in the near-infrared spectral region. Electrochemical and optical properties of [Ni(dpedt)2] depend strongly on the nickel bis(1,2-dithiolene) core and very slightly on the alkyl chain lengths or configurations. These highly soluble coordination compounds are potential candidates as acceptor solution-processable materials for active layers in organic electronic devices, such as field effect transistors or photovoltaic devices.