Résumé
The reactions of the dimers [Ru(η6-arene)Cl2]2] (arene=C6H5Me, p-MeC6H4i-Pr or C6Me6) with (n-Bu4N)2[Mo2O7] have been investigated in methanol or acetonitrile, in some cases in the presence of MeC(CH2OH)3. A series of complexes with various nuclearities, [{Ru(η6-arene)}Mo2O4{MeC(CH2O)3}2] and [{Ru(η6-arene)}2Mo2O6(OMe)4] (arene=p-MeC6H4i-Pr), (n-Bu4N)2[{Ru(η6-arene)}2Mo6O20(OMe)2] (arene=C6H5Me or C6Me6) and (n-Bu4N)2[{Ru(η6-arene)}2Mo6O18{MeC(CH2O)3}2] (arene=C6Me6), has been obtained. The crystal structures of these compounds have been determined by X-ray crystallography. The clusters [{Ru(η6-arene)}Mo2O4{MeC(CH2O)3}2], [{Ru(η6-arene)}2Mo2O6(OMe)4], [{Ru(η6-arene)}2Mo6O20(OMe)2]2− and [{Ru(η6-arene)}2Mo6O18{MeC(CH2O)3}2]2− were derived from known oxoalkoxopolymolybdates, [Mo3O6(OMe){MeC(CH2O)3}2]−, [Mo4O10(OMe)6]2−, [Mo8O24(OMe)4]4− and [Mo8O20(OMe)4{MeC(CH2O)3}2]2−, respectively, through the formal replacement of d0-fac-{MoO2(OMe)}+ groups by topologically equivalent {Ru(η6-arene)}2+ units and, for the octanuclear trisalkoxo derivatives, by further substitution of two oxo ligands for the two remaining methoxo ligands.
A series of (η6-arene)ruthenium polyoxomolybdates has been synthesized by self-assembly reactions between (n-Bu4N)2[Mo2O7] and [Ru(arene)Cl2]2 in non-aqueous solutions, in some cases in the presence of MeC(CH2OH)3, and structurally characterized. The oxometal frameworks of these clusters are related to those of previously described isopolyoxo(alkoxo)molybdates through the formal replacement of fac-{MoO2(OCH3)}+ groups by {Ru(η6-arene)}2+ units. The concept of topologically equivalent units provides a useful link between organometallic oxides and polyoxometalates.