Synthesis,structural characterization,and electrocatalytic studies of alpha beta beta alpha-(Zn~(II)OH2)2(Fe~(III))2(X2W15O56)_2~(14-)(X=P or As)

摘要

The synthesis and characterization of the previously unknown mixed-metal sandwich-type Wells-Dawson complexes,a(3(3a-[(Zn~(II)OH2)2(Fe~(III))2(P2W15O56)2]~(14-)(Zn2Fe2P4)and alpha beta beta alpha-[(Zn~(II)OH2)2(Fe~(III))2(As2W15O56)2]~(14-)(Zn2Fe2As4),are described.The complexes are prepared by the reaction of Zn(II)with the divacant lacunary species,alpha alpha alpha alpha-[(NaOH2)2(Fe~(III))2(P2W15O56)2]~(16-)and alpha alpha alpha alpha-[(NaOH2)2(Fe~(III))2(As2W15O56)2]~(16-),respectively,and are characterized by X-ray crystallography,infrared and NMR spectroscopy,elemental and thermogravimetric analyses,differential scanning calorimetry,and cyclic voltammetry.Like their analogues,alpha beta beta alpha-[(Mn~(II)OH2)2(Fe~(III))2(P2W15O56)2]~(14-)(Mn2Fe2P4)and alpha beta beta alpha-[(Mn~(II)OH2)2(Fe~(III))2(As2W15O56)2]~(14-)(Mn2Fe2As4),the remarkable stability observed for these complexes from pH 0 to at least 6 has permitted a comprehensive evaluation of their electrocatalytic abilities toward the reduction of O2,H2O2,HNO2 and NO.A comparison of the properties of the mixed-metal Zn(II)and Mn(II)complexes is provided.