A novel layer formed by paradodecatungstate clusters and {Cu(en)2}2+ bridging groups:: Synthesis and characterization of [{Cu(en)2}4(H4W12O42)] • 9H2O

A novel two-dimensional solid, [{Cu(en)(2)}(4)(H4W12O42)]center dot 9H(2)O (en = ethylenediamine), has been prepared under mild hydrothermal conditions. Single crystal X-ray diffraction revealed that each paradodecatungstate [H4W12O42](8-) Cluster in the title compound is connected with its four adjacent clusters through eight {Cu(en)(2)}(2+) bridging groups into a two-dimensional layered structure. Its cyclic voltammetric behavior in aqueous electrolyte demonstrated that its modified carbon paste electrode has a good stability. A probe reaction indicated that the catalytic activity of paradodecatungstates in epoxidation of maleic anhydride has been enhanced by assembling paradodecatungstate clusters into extended structures. (c) 2007 Published by Elsevier Masson SAS.