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A Redox‐Active Ligand as a Reservoir for Protons and Electrons: O 2 Reduction at Zirconium(IV)
Author(s) -
Lu Feng,
Zarkesh Ryan A.,
Heyduk Alan F.
Publication year - 2012
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201100798
Subject(s) - chemistry , deprotonation , ligand (biochemistry) , protonation , redox , zirconium , amide , crystal structure , crystallography , medicinal chemistry , inorganic chemistry , organic chemistry , ion , biochemistry , receptor
The [ONO] ligand {(ONO cat ) 3– = bis(3,5‐di‐ tert ‐butyl‐2‐phenoxy)amide} can be installed onto zirconium(IV) in two different protonation states. The reaction of (ONO cat ) 3– with ZrCl 4 afforded the octahedral complex (ONO cat )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 (ONO cat )H 3 was doubly deprotonated and treated with ZrCl 4 , the complex (ONHO)ZrCl 2 (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 [(ONO q )ZrCl 2 (μ‐OH)] 2 ( 3 ), which shows that the [ONO] ligand platform can serve as both an electron and proton reservoir in small‐molecule reactions.