Polyanions [{B-α-(OH)Fe2(PW10O37)}2{o-R–C6H4–AsO3)}2]12– (R = NH2 (1) and NO2 (2)) represent the first polyoxotungstates functionalized by both organoarsonates and FeIII. 1 and 2 comprise the rare dilacunary Keggin-type phosphotungstate {B-α-PW10O37}9– isomer that coordinates FeIII ions to form {B-α-FeIII 2PW10} complexes linked into dimers via two organoarsonate groups. The title polyanions have been isolated as crystalline materials and fully characterized via single-crystal and powder X-ray diffraction, elemental analysis and IR and UV–vis spectroscopies, including solution stability studies. In addition, their electrochemical and magnetic properties have been characterized.

Solution-stable tris(hydroxymethyl)aminomethane-functionalized Fe(III)-containing polyoxotungstates exhibit an unusual anchoring mode of the triol moieties, with one −NH2 and one −CH2OH groups remaining accessible for post-functionalization or chemisorption. The redox-active title compounds...