Wydział Chemii

Krystyna Rachlewicz

Lechosław Latos-Grażyński

E. Vogel

2000

Inorganic Chemistry

39

3247-3251

10.1021/ic991417c

Naukowa

Angielski

Artykuł

The iron(III) 2,7,12,17-tetra-n-propylporphycene (TPrPc)Fe^IIICl is reduced using aqueous sodium dithionite or zinc amalgam to produce (TPrPc)Fe^II. The ¹H NMR spectrum of (TPrPc)Fe^II (293 K; δ (ppm):  pyrrole, −37.52; meso, 71.56; α-CH₂, 27.47; β-CH₂, 8.92; γ-CH₃, 5.55) can be accounted for by the planar unligated iron(II) porphycene with an S = 1 ground electronic state. Introduction of dioxygen into a toluene-d₈ solution of (TPrPc)Fe^II at 203 K results in the formation of the (μ-peroxo)diiron(III) porphycene (TPrPc)Fe^III−O−O−Fe^III(TPrPc). The value of the chemical shift of the pyrrole resonances (17.99 ppm at 203 K) of this species and its distinct non-Curie behavior imply strong antiferromagnetic iron(III)−iron(III) coupling via a μ-peroxo bridge. The (TPrPc)Fe^III−O−O−Fe^III(TPrPc) intermediate is stable at 203 K, but it converts into the (μ-oxo)diiron complex (TPrPc)Fe^III−O−Fe^III(TPrPc) upon warming above 203 K. Reaction of (TPrPc)Fe^III−O−O−Fe^III(TPrPc) with a nitrogen bases (B:  pyridine-d₅, 1-methylimidazole) results in a homolytic cleavage of the μ-peroxo bridge to form the ferryl porphycene complex B(TPrPc)Fe^IVO (¹H NMR (223 K), δ (ppm):  pyrrole, −1.32; meso, 11.80). B(TPrPc)Fe^IVO reacts with triphenylphosphine at 223 K to yield triphenylphosphine oxide.

Nuclear magnetic resonance spectroscopy, Oxides, Pyrroles, Redox reactions, Resonance structures

https://doi.org/10.1021/ic991417c

https://www.acs.org/content/acs/en.html