Reactions of [Ru(NO)Cl 5 ] 2- with pseudotrilacunary {XW 9 O 33 } 9- (X = As III , Sb III ) anions.

Reactions of [Ru(NO)Cl ₅ ] ^2- with pseudotrivacant B-α-[XW ₉ O ₃₃ ] ^9- (X = As ^III , Sb ^III ) at 160 °C result in the rearrangement of polyoxometalate backbones into {XM ₁₈ } structures. In the case of arsenic, oxidation of As ^III to As ^V takes place with the formation of a mixture of plenary and monosubstituted Dawson [As ₂ W ₁₈ O ₆₂ ] ^6- and [As ₂ W ₁₇ Ru(NO)O ₆₁ ] ^7- anions, of which the latter was isolated as Me ₂ NH ₂ ⁺ (DMA-1a and DMA-1b) and Bu ₄ N ⁺ (Bu ₄ N-1) salts and fully characterized. Both α ₁ and α ₂ isomers of [As ₂ W ₁₇ Ru(NO)O ₆₁ ] ^7- were present in the reaction mixture; pure [α ₂ -As ₂ W ₁₇ Ru(NO)O ₆₁ ] ^7- was isolated as the Bu ₄ N ⁺ salt. In the case of antimony, [SbW ₉ O ₃₃ ] ^9- is converted into a mixture of [SbW ₁₈ O ₆₀ ] ^9- and [SbW ₁₇ {Ru(NO)}O ₅₉ ] ^10- . The formation of trisubstituted [SbW ₁₅ {Ru(NO)} ₃ O ₅₇ ] ^12- as a minor byproduct was detected by HPLC-ICP-AES. The monosubstituted [SbW ₁₇ {Ru(NO)}O ₅₉ ] ^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.