Multidentate aryloxide and oxo-aryloxide complexes of antimony: synthesis and structural characterization of η4-No-C6H4O3SbOSMe2, η3-No-C6H4OHo-C6H4O2Sb2µ2-O2and η3-PhNo-C6H4O2Sb4µ3-O2Dedicated to the memory of Ian P. Rothwell, a true pioneer in the area of aryloxide chemistry.

Antimony compounds that feature multidentate aryloxide ligands, namely η4–No-C6H4O3SbOSMe2, η3-No-C6H4OHo-C6H4O2Sb2µ2-O2, and η3-PhNo-C6H4O2Sb4µ3-O2have been synthesized from No-C6H4OH3and PhNo-C6H4OH2and structurally characterized by X-ray diffraction. While η4-No-C6H4O3SbOSMe2 exists as a discrete mononuclear species, the oxo complexes η3-No-C6H4OHo-C6H4O2Sb2µ2-O2and η3-PhNo-C6H4O2Sb4µ3-O2are multinuclear. Specifically, the dinuclear fragment η3-No-C6H4OHo-C6H4O2Sb2µ2-O exists in a dimeric form due to the bridging oxo ligand participating in an intermolecular hydrogen bonding interaction, while the dinuclear fragment η3-PhNo-C6H4O2Sb2µ-O exists in a dimeric form due to the bridging oxo ligand serving as a donor to the antimony of a second fragment. The structures of η3-No-C6H4OHo-C6H4O2Sb2µ2-O2and η3-PhNo-C6H4O2Sb4µ3-O2, therefore, indicate that an oxo ligand bridging two SbIIIcenters is sufficiently electron rich to serve as both an effective hydrogen bond acceptor and as a ligand for an additional SbIIIcenter.