Title: Ligand Noninnocence in Iron Corroles: Insights from Optical and X-ray Absorption Spectroscopies and Electrochemical Redox Potentials

Abstract

Two new series of iron meso-tris(para-X-phenyl)corrole (TpXPC) complexes, Fe[TpXPC]Ph and Fe[TpXPC]Tol, in which X=CF₃, H, Me, and OMe, and Tol=p-methylphenyl (p-tolyl), have been synthesized, allowing a multitechnique electronic–structural comparison with the corresponding FeCl, FeNO, and Fe₂(μ-O) TpXPC derivatives. Optical spectroscopy revealed that the Soret maxima of the FePh and FeTol series are insensitive to the phenyl para substituent, consistent with the presumed innocence of the corrole ligand in these compounds. Accordingly, we may be increasingly confident in the ability of the substituent effect criterion to serve as a probe of corrole noninnocence. Furthermore, four complexes—Fe[TPC]Cl, Fe[TPC](NO), {Fe[TPC]}₂O, and Fe[TPC]Ph—were selected for a detailed XANES investigation of the question of ligand noninnocence. The intensity-weighted average energy (IWAE) positions were found to exhibit rather modest variations (0.8 eV over the series of corroles). The integrated Fe-K pre-edge intensities, on the other hand, vary considerably, with a 2.5 fold increase for Fe[TPC]Ph relative to Fe[TPC]Cl and Fe[TPC](NO). Given the approximately C_4v local symmetry of the Fe in all the complexes, the large increase in intensity for Fe[TPC]Ph may be attributed to a higher number of 3d holes, consistent with an expected Fe^IV-like description, in contrast to Fe[TPC]Cl and Fe[TPC](NO), in which the Femore » is thought to be Fe^III-like. In conclusion, these results afford strong validation of XANES as a probe of ligand noninnocence in metallocorroles. Electrochemical redox potentials, on the other hand, were found not to afford a simple probe of ligand noninnocence in Fe corroles.« less

Authors:

Ganguly, Sumit ^[1]; Giles, Logan J. ^[2]; Thomas, Kolle E. ^[3]; Sarangi, Ritimukta ^[2]; Ghosh, Abhik  ^[3]

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+ Show Author Affiliations

1. Univ. of Tromso - The Arctic Univ. of Norway (UiT), Tromso (Norway). Dept. of Chemistry and Center for Theoretical and Computational Chemistry
2. SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
3. Univ. of Tromso - The Arctic Univ. of Norway (UiT), Tromso (Norway). Dept. of Chemistry and Center for Theoretical and Computational Chemistry

Publication Date:

Fri Oct 06 00:00:00 EDT 2017

Research Org.:

SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER); Research Council of Norway; National Institutes of Health (NIH)

OSTI Identifier:

1425580

Grant/Contract Number:  

AC02-76SF00515; P41GM103393

Resource Type:

Accepted Manuscript

Journal Name:

Chemistry - A European Journal

Additional Journal Information:

Journal Volume: 23; Journal Issue: 60; Journal ID: ISSN 0947-6539

Publisher:

ChemPubSoc Europe

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; corroles; iron; noninnocence; XANES; X-ray absorption spectroscopy