A Redox-Active Ligand as a Reservoir for Protons and Electrons: O-2 Reduction at Zirconium(IV)

作者：Lu Feng; Zarkesh Ryan A; Heyduk Alan F^*

来源：European Journal of Inorganic Chemistry, 2012, (3): 467-470.

DOI：10.1002/ejic.201100798

• Redox-active ligands
• Zirconium
• Oxygen reduction
• Redox chemistry
• Structure elucidation

The [ONO] ligand {(ONOcat)(3-) = bis(3,5-di-tert-butyl-2-phenoxy)amide} can be installed onto zirconium(IV) in two different protonation states. The reaction of (ONOcat)(3-) with ZrCl4 afforded the octahedral complex (ONOcat)ZrCl-THF)(2) (1). This complex, characterized in the solid state by single-crystal X-ray diffraction and in solution by NMR, UV/Vis, and IR spectroscopy, is assigned as a zirconium(IV) complex coordinated to the fully reduced form of the [ONO] redox-active ligand. When (ONOcat)H-3 was doubly deprotonated and treated with ZrCl4, the complex (ONHO) ZrCl2-(THF) (2) was isolated, in which one ligand proton remains on the [ONO] ligand. Exposure of 2 to dry O-2 resulted in a four-electron, two-proton reaction to form the bis(hydroxo) complex [(ONOq) ZrCl2(mu-OH)](2) (3), which shows that the [ONO] ligand platform can serve as both an electron and proton reservoir in small-molecule reactions.

• 出版日期2012-1