Reactions of [Ru(NO)Cl5]2- with pseudotrilacunary {XW9O33}9- (X = AsIII, SbIII) anions.

Abstract

Reactions of [Ru(NO)Cl5]2- with pseudotrivacant B-α-[XW9O33]9- (X = AsIII, SbIII) at 160 °C result in the rearrangement of polyoxometalate backbones into {XM18} structures. In the case of arsenic, oxidation of AsIII to AsV takes place with the formation of a mixture of plenary and monosubstituted Dawson [As2W18O62]6- and [As2W17Ru(NO)O61]7- anions, of which the latter was isolated as Me2NH2+ (DMA-1a and DMA-1b) and Bu4N+ (Bu4N-1) salts and fully characterized. Both α1 and α2 isomers of [As2W17Ru(NO)O61]7- were present in the reaction mixture; pure [α2-As2W17Ru(NO)O61]7- was isolated as the Bu4N+ salt. In the case of antimony, [SbW9O33]9- is converted into a mixture of [SbW18O60]9- and [SbW17{Ru(NO)}O59]10-. The formation of trisubstituted [SbW15{Ru(NO)}3O57]12- as a minor byproduct was detected by HPLC-ICP-AES. The monosubstituted [SbW17{Ru(NO)}O59]10- anion was isolated as DMAH+ (DMA-2) and mixed inorganic cation (CsKNa-2) salts and characterized by XRD, HPLC-ICP-AES, EA and TGA techniques. X-ray analysis shows the presence of the {Ru(NO)}-group in the 6-membered ("equatorial") belt of the Sb-free hemisphere. The experimental findings were confirmed and interpreted by means of quantum chemical calculations.