Synthesis and near infrared electrochromic properties of metallodithiolene complexes

Four metallodithiolene complexes [4,8-bis(octyloxy)-1,3,5,7-tetrathia]Icdi[1,1'-bis(diphenylphosphino)ferroceneIcpalladium(II)] (3), [4,8-bis(octyloxy)-1,3,5,7-tetrathia]di[1,3-bis(diphenylphosphino)propaneIcnickel(II)] (4), [4,8-bis(octyloxy)-1,3,5,7-tetrathia] Ic[1,1'-bis(diphenylphosphino)ferroceneIcpalladium(II)]Ic[1,3-bis(diphenylphosphino)propane center dot nickel(II)] (5) and di[4,8-bis (octyloxy)-1,3,5,7-tetrathia]Ic[1,1'-bis(diphenylphosphino)ferroceneIcpalladium(II)]Icnickel(II) (6) were synthesized and the near-infrared (NIR) electrochromic properties were studied. The spectroelectrochemical spectra and the electrochromic parameters such as optical contrast, switching time, optical density change, electrochromic efficiency and optical attenuation of complexes 3-6 were investigated in detail. The symmetric binuclear complex 4 showed relatively high electrochromic efficiency of 63.0 and 75.4 cm(2)/C both in the two oxidation states. The complexes exhibited excellent electroactive/electrochromic stability characterized by chronoamperometry (> 4000 cyclic switches).