Polyoxoanion-supported, atomically dispersed cyclooctadieneruthenium(II) complexes

Abstract

The cation [Ru(C₈H₁₂)]²⁺ was supported on [P₃O₉]^3–, [V₄O₁₂]^4– and [Nb₂W₄O₁₉]^4– polyoxoanions. All the complexes were stable in air and were characterized by elemental and thermogravimetric analysis, IR, ¹H, ¹³C and ³¹P NMR spectroscopy. The crystal and molecular structure of [NBu₄][Ru(C₈H₁₂)(MeCN)-(P₃O₉)]·Et₂O has been determined [space group C2/c, a= 38.359(4), b= 9.907(5), c= 26.437(3)Å, β= 127.720(4)°]. Ruthenium(II) is octahedrally co-ordinated to the two C₈H₁₂-diene groups, to one acetonitrile molecule and through three O atoms to the P₃O₉^3– ligand. In the case of [Ru(C₈H₁₂)(MeCN)₂-(HV₄O₁₂)^– and [Ru(C₈H₁₂)(MeCN)₂(V₄O₁₂)]^2– where a bidentate co-ordination to the polyanion is observed, two MeCN molecules are co-ordinated by Ru, resulting in the 18-valence-electron configuration. The [Nb₂W₄O₁₉]^4– anion behaves differently: its reaction with [RuCl(C₈H₁₂)(MeCN)₃]PF₆ leads to a product which, on the basis of IR, elemental analysis and the literature, we formulate as [NBu₄]₃[{RuCl(C₈H₁₂)(MeCN)}₅(Nb₂W₄O₁₉)₂]·3H₂O. In this case two Nb₂W₄O₁₉^4– anions are probably linked, face to face, by five organometallic centres.