Photochromic and electrochromic properties of oxo-centred triruthenium compounds with a dithienylethene bis(phosphine) ligand

The reaction of 1,2-bis(5-(diphenylphosphino)-2-methylthien-3-yl) cyclopentene (PPh2-DTE-PPh2) with the triruthenium cluster precursor [Ru3O(OAc)(6)(py)(2)(CH3OH)](PF6) (1) gave monomeric or dimeric derivatives [Ru3O(OAc)(6)(py)(2){PPh2-DTE-PPh2}](PF6) ([2]PF6) and [{Ru3O(OAc)(6)(py)(2)}(2)-{mu-PPh2-DTE-PPh2}](PF6)(2) ([(3)]PF6). Reduction of [2](+) and [3](2+) afforded one-or two-electron-reduced neutral products Ru3O(OAc)(6)(py)(2){PPh2-DTE-PPh2} (2) and {Ru3O(OAc)(6)(py)(2)}(2){m-PPh2-DTE-PPh2} (3), respectively. These triruthenium complexes show remarkable photochromism through photochemical ring-closing (UV light irradiation) and ring-opening (Vis light irradiation) processes as well as electrochromic properties through oxidation/reduction in the triruthenium cluster. Both the photochromic and electrochromic properties of 2 and 3 are highly reversible.