91711-74-9Relevant articles and documents
Electronic Structure of a Formal Iron(0) Porphyrin Complex Relevant to CO2 Reduction
R?melt, Christina,Song, Jinshuai,Tarrago, Maxime,Rees, Julian A.,Van Gastel, Maurice,Weyhermüller, Thomas,Debeer, Serena,Bill, Eckhard,Neese, Frank,Ye, Shengfa
, p. 4745 - 4750 (2017)
Iron porphyrins can act as potent electrocatalysts for CO2 functionalization. The catalytically active species has been proposed to be a formal Fe(0) porphyrin complex, [Fe(TPP)]2- (TPP = tetraphenylporphyrin), generated by two-electron reduction of [FeII(TPP)]. Our combined spectroscopic and computational investigations reveal that the reduction is ligand-centered and that [Fe(TPP)]2- is best formulated as an intermediate-spin Fe(II) center that is antiferromagnetically coupled to a porphyrin diradical anion, yielding an overall singlet ground state. As such, [Fe(TPP)]2- contains two readily accessible electrons, setting the stage for CO2 reduction.
Nature of iron(I) and iron(0) tetraphenylporphyrin complexes. Synthesis and molecular structure of (dibenzo-18-crown-6)bis(tetrahydrofuran)sodium (meso-tetraphenylporphinato)ferrate and bis[tris(tetrahydrofuran)sodium] (meso-tetraphenylporphinato)ferrate
Mashiko, Toshio,Reed, Christopher A.,Haller, Kenneth J.,Scheidt, W. Robert
, p. 3192 - 3196 (2008/10/08)
A synthetic and structural investigation of the so-called iron(I) and iron(0) tetraphenylporphyrin complexes, [Fe(TPP)]- and [Fe(TPP)]2-, resolves a number of the existing ambiguities about their identity. [Fe(TPP)]- has a low-spin S = 1/2 state and is devoid of axial ligation at least in the solid state where it crystallizes as the purple, air-sensitive [Na(dibenzo-18-crown-6)(THF)2]+ salt. Crystal data: C72H68O8N4FeNa, monoclinic, space group P21/m, a = 12.796 (2) ?, b = 21.861 (4) ?, c = 12.108 (2) ?, β = 103.47 (1)°, Z = 2; Fe-Np(av) = 1.980 (6) ?. Analysis of the structural data requires inclusion of substantial iron(II) π-radical anion character in the previously favored iron(I) formulation. The green dianion [Fe(TPP)]2- has been isolated for the first time. It is diamagnetic and crystallizes in a tightly ion-paired structure where two [Na(tetrahydrofuran)3]+ cations interact with a pair of porphinato nitrogen atoms (Na?N = 2.784 (4), 2.825 (4) ?) above and below the porphyrin plane. The porphinato core bond lengths reveal considerable π-radical anion character. Crystal data: C68H76O6N4FeNa2, triclinic, space group P1, a = 11.877 (3) ?, b = 13.242 (3) ?, c = 11.242 (2) ?, α = 113.69 (2)°, β = 110.01 (2)°, γ = 77.55 (2)°, Z = 1; Fe-Np(av) = 1.968 (1) ?.
