Triphenylantimony( v) Catecholates and o ‐Amidophenolates: Reversible Binding of Molecular Oxygen

Novel neutral antimony( V ) complexes were isolated as crystalline materials and characterized by IR and NMR spectroscopy: o ‐amidophenolate complexes [4,6‐di‐ tert ‐butyl‐ N ‐(2,6‐dimethylphenyl)‐ o ‐amidophenolato]triphenylantimony( V ) (Ph 3 Sb[AP‐Me], 1 ) and [4,6‐di‐ tert ‐butyl‐ N ‐(2,6‐diisopropylphenyl)‐ o ‐amidophenolato]triphenylantimony( v) (Ph 3 Sb[AP‐ i Pr], 2 ); catecholate complexes (3,6‐di‐ tert ‐butyl‐4‐methoxycatecholato)triphenylantimony( V ) (Ph 3 Sb[(MeO)Cat], 3 ), its methanol solvate 3 ⋅CH 3 OH ( 4 ); (3,6‐di‐ tert ‐butyl‐4,5‐di‐methoxycatecholato)triphenylantimony( V ) (Ph 3 Sb[(MeO) 2 Cat], 5 ) and its acetonitrile solvate 5 ⋅CH 3 CN ( 6 ). Complexes 1 – 7 were synthesized by oxidative addition of the corresponding o ‐iminobenzoquinones or o ‐benzoquinones to Ph 3 Sb. In the case of the phenanthrene‐9,10‐diolate (PhenCat) ligand, two different complexes were isolated: Ph 3 Sb[PhenCat] ( 7 ) and [Ph 4 Sb] + [Ph 2 Sb(PhenCat) 2 ] − ( 8 ). Complexes 7 and 8 were found to be in equilibrium in solution. Molecular structures of 2 , 4 , 6 , and 8 were determined by X‐ray crystallography. Complexes 1 – 7 reversibly bind molecular oxygen to yield Ph 3 Sb[L‐Me]O 2 ( 9 ), Ph 3 Sb[L‐ i Pr]O 2 ( 10 ), Ph 3 Sb[(MeO)L′]O 2 ( 11 ), Ph 3 Sb[(MeO) 2 L′]O 2 ( 12 ) and Ph 3 Sb[PhenL′]O 2 ( 13 ), which contain five‐membered trioxastibolane species (where L is the O,O′,N‐coordinated derivative of a 1‐hydroperoxy‐6‐( N ‐aryl)‐iminocyclohexa‐2,4‐dienol, and L′ the O,O′,O′′‐coordinated derivative of 6‐hydroperoxy‐6‐hydroxycyclohexa‐2,4‐dienone). Complexes 9 – 13 were characterized by IR and 1 H NMR spectroscopy and X‐ray crystallography.