| Abstract
| - New RuII and OsII derivatives of the monovacant [α-PW11O39]7- anion ([PW11O39{M(DMSO)3(H2O)}]5- (M= Ru (1), Os (2)) and [PW11O39{Os(η6-p-cym)(H2O)}]5- (3)) have been synthesized and characterized. Thebinding mode of the d6-{MIIL3(H2O)}2+ moieties in these compounds is similar to that in the previouslydescribed [PW11O39{Ru(η6-p-cym)(H2O)}]5- (4) complex: bidentate, on two nonequivalent oxygen atoms ofthe lacuna, leading to a loss of the Cs symmetry of the parent anion, which thus plays the role of a prochiralbidentate ligand. The density functional theory (DFT) (B3PW91) computation of the lowest unoccupiedmolecular orbitals of the {ML3(H2O)}2+ (M = Os, Ru; L3 = fac-(DMSO)3, η6-C6H6) fragments reveals thesimilarities between their electrophilic properties. The origin of the regioselectivity of the grafting wasinvestigated through a DFT (B3PW91) analysis of (i) the highest occupied molecular orbital of [α-PW11O39]7-and (ii) the relative energies of the different potential regioisomers obtained by a bidentate grafting of the{ML3(H2O)}2+ moiety onto the lacuna of [α-PW11O39]7-. The role of the water ligand in the stabilization ofthis peculiar structure was studied.
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