Water Oxidation Reaction Mediated by an Octanuclear Iron‐Oxo Cluster

Abstract

In the original article1 the compound “[FeCl3(µ-4-tBu-pzH)2]” was erroneously termed “mer-[FeCl3(µ-4-tBu-pzH)2]” both in the text (on page 1) and in Scheme 1. A new Scheme 1 is provided where “mer-[FeCl3(µ-4-tBu-pzH)2]” is now correctly shown as “[FeCl3(µ-4-tBu-pzH)2]”. We also inadvertently omitted to include a citation2 to indicate the source of the sentence in quotation marks in the conclusions of our original article1 (already cited in our original article1 as ref.[10]). We deeply regret our oversight. The sentence in question should read: The question that arises then is “why Nature has ignored such a simple and efficient redox catalyst in favor of its sulfur analogues?”[10] In the Supporting Information of the original article1 we did not include the FTIR spectrum of compound 2 and its 18O-labeled analogue. Also in the Supporting Information in the section “Synthesis of [Fe(µ-4-tBu-pz)4Cl2][FeCl4]/[Fe(µ-4-tBu-pz)2Cl3] (1)”, the compound “Na-4-tBu-pz” was erroneously written. The correct compound is “4-tBu-pzH”. The original Supporting Information has now been updated to include the FTIR spectrum of 2 (Figure S4) in the range 450–1550 cm–1and the correct compound. Following a comment by Professor Raphael Raptis, Florida International University, we looked into the Mössbauer spectra of compound 2 more carefully. We found an error – our analysis of the different Mössbauer spectrum of 2 relative to 3 is incorrect. In fact, 2 and 3 have comparable Mössbauer spectra. We would therefore like to replace Figure 2 in the original article1 with the following new Figure 2, and Table S1 in the Supporting Information has also been updated to reflect the corrected isomer shift (δ)/Quadrupole splitting (ΔEQ) parameters of 2. The corresponding corrected text accompanying Figure 2 (on page 2) (on page 2; caption corrected) is as follows: At zero magnetic field, the Mössbauer spectrum of 2 consists of two quadrupole doublets with isomer shift (δ)/Quadrupole splitting (ΔEQ) parameters of 0.43/0.33 mm s–1 (Figure 2b; blue shaded area) and 0.39/0.70 mm s–1 (orange shaded area). The δ values of both doublets are characteristic of high-spin iron(III) centers; [20] the iron center with lower δ and higher ΔEQ is assigned to the five-coordinate outer Fe(4-tBu-pz)3Cl units (Feo), whereas the one with higher δ and lower ΔEQ corresponds to the octahedral iron center (Fec) of the inner Fe4O4 core. Notably, the δ and ΔEQ values associated with the Fec and Feo centers in 2 are similar to that reported previously for the Fec and Feo centers in [Fe8(µ4-O)4(µ-pz)12Cl4] (3) involving the unsubstituted pz ligand (Table S1).[11] The similar δ and ΔEQ values in 2 and 3 are consistent with the predominance of the Oh (for Fec) and TBP geometries (τ[21] = 0.90 for both Feo centers in 2 and 3) for both complexes. A sentence in the Conclusion is corrected accordingly to remove any reference to the differences in the Mössbauer spectra of compounds 2 and 3. The correct sentence is: Nevertheless, the electronic structure of 2 is significantly different from that of the [Fe8(µ4-O)4(µ-pz)12Cl4] complex 3, as evidenced by an approximately 300 mV shift of redox potentials to more positive values in 2. We sincerely apologize for these mistakes and thank Professor Raptis for bringing these points to our attention. The Authors