Dimeric assemblies of lanthanide-stabilised dilacunary Keggin tungstogermanates: A new class of catalysts for the selective oxidation of aniline

In this work we demonstrate the efficiency of some dimeric [Ln4(H2O)6(β-GeW10O38)2]12− anions composed of lanthanide-stabilised dilacunary Keggin tungstogermanate fragments (ββ-Ln4, Ln = Dy, Ho, Er, Tm) as heterogeneous catalysts for the organic phase oxidation of aniline with hydrogen peroxide. The results obtained evidence total conversion of aniline at room temperature, as well as full selectivity towards nitrosobenzene, and the catalysts are able to retain both their activity and selectivity after several runs. Peroxopolyoxometalate intermediaries have been identified as the catalytically active species during the aniline-to-nitrosobenzene oxidation process.

The authors thank the Generalitat Valenciana and FEDER (PROMETEO2/2014/010), and MICINN and Plan E (CTQ2012-31762) for the financial support. J.M.G.Z. acknowledges support from Eusko Jaurlaritza/Gobierno Vasco (IT477-10), MINECO (MAT2013-48366-C2-2P) and UPV/EHU (UFI11/53).