Ionic crystals based on Keggin anion and mixed-valent diruthenium tetracetate: [Ru_2(CH_3COO)_4(H_2O)_2]_2[H_nXW_(12)O_(40)] ·[Ru_2(CH_3COO)_4(H_2O)Cl] ·12H_2O (X = B, Si, Ge)

摘要

Three new ionic crystals based on Keggin anion and mixed-valent diruthenium tetracetate, [Ru_2(CH_3CO_2)_4(H_2O)_2]_2[H_nXW_(12)O_(40)] ·[Ru_2(CH_3CO_2)_4(H_2O)Cl]-12H_2O {X = B, n = 3 (1); X = Si, n = 2 (2); X = Ge, n = 2 (3)} , have been prepared in acidic aqueous solution at about pH 3.0 by reaction of K_4BW_(12)O_(40)-mH_2O, K_8SiW_(11)O_(39)-mH_2O and K_8GeW_(11)O_(39)-mH_2O with diruthenium tetracetate Ru_2(CH_3. COO)_4Cl, respectively, and their structures were determined by X-Ray diffraction analysis. They are isostructural structure with the ratio of heteropolytungstate anion, Ru_2(CH_3CO_2)_4~+ cation and neutral molecular Ru_2(CH_3CO_2)_4Cl of 1:2:1. The cyclic voltammetry in 0.5 M KNO_3 aqueous solution at pH 3.0 show the respective electrochemical behaviors of the W-centers and Ru_2-centers for these three complexes. Magnetic data analysis shows that diruthenium units display the ground state electronic configuration π~(*2)δ~* with large positive D value.