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On the Iron(V) Reactivity of an Aggressive Tail‐Fluorinated Tetraamido Macrocyclic Ligand (TAML) Activator
Author(s) -
Ren Qizhi,
Guo Yisong,
Mills Matthew R.,
Ryabov Alexander D.,
Collins Terrence J.
Publication year - 2015
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.201500001
Subject(s) - chemistry , reactivity (psychology) , macrocyclic ligand , thioanisole , ligand (biochemistry) , electron transfer , dimer , hydrogen atom abstraction , cyclohexane , photochemistry , medicinal chemistry , oxidizing agent , stereochemistry , crystallography , catalysis , hydrogen , organic chemistry , crystal structure , alternative medicine , medicine , biochemistry , receptor , pathology
The electronic properties of iron tetraamido macrocyclic ligand (TAML) activators of peroxides can be finely and coarsely tuned by varying the substituents on the “head” and “tail” macrocyclic components, respectively. By examining the reactivity of the TAML oxidoiron(V) complex with head‐NO 2 and tail‐F substituents, one is able to compare the impact of significantly reduced macrocyclic tetraamide donor capacity on fundamental processes such as hydrogen‐atom abstraction, oxygen‐atom transfer, and electron transfer by using prior studies with more electron‐rich TAML systems. Herein, we demonstrate that the oxidoiron(V) form 3c can be generated by treatment of [Fe{4‐NO 2 C 6 H 3 ‐1,2‐(N 2 COCMe 2 N 3 CO) 2 CF 2 ( Fe–N 2 )( Fe–N 3 )}(OH 2 )] – ( 1c ) with m ‐chloroperoxybenzoic acid ( m CPBA) in MeCN at –40 °C. The oxidation proceeds through the intermediacy of the μ‐oxo[iron(IV)] 2 dimer. The overall rate of the Fe III →Fe V conversion by m CPBA is slightly faster for 1c than that of its less electron‐rich precursor [Fe{C 6 H 4 ‐1,2‐(N 1 COCMe 2 N 2 CO) 2 CMe 2 ( Fe–N 1 )( Fe–N 2 )}(OH 2 )] – ( 1a ). Nevertheless, the oxidative reactivity of 3c toward thioanisole and the hydrocarbons ethylbenzene and cyclohexane exceeds that of 3a by 4.3, 2.1, and 2.6 times, respectively. The reactivity of 3c is significantly greater towards ethylbenzene than that of the oxidoiron(V) species 3b derived from [Fe{C 6 H 4 ‐1,2‐(N 1 COCMe 2 N 2 CO) 2 NMe( Fe–N 1 )( Fe–N 2 )}(OH 2 )] – ( 1b ).