Alkali cation effects on redox-active formazanate ligands in iron chemistry

Broere, D. L.J., Mercado, B. Q., Bill, E., Lancaster, K. M., Sproules, S. and Holland, P. L. (2018) Alkali cation effects on redox-active formazanate ligands in iron chemistry. Inorganic Chemistry, 57(16), pp. 9580-9591. (doi: 10.1021/acs.inorgchem.8b00226) (PMID:29629752)

Abstract

Noncovalent interactions of organic moieties with Lewis acidic alkali cations can greatly affect structure and reactivity. Herein, we describe the effects of interactions with alkali-metal cations within a series of reduced iron complexes bearing a redox-active formazanate ligand, in terms of structures, magnetism, spectroscopy, and reaction rates. In the absence of a crown ether to sequester the alkali cation, dimeric complexes are isolated wherein the formazanate has rearranged to form a five-membered metallacycle. The dissociation of these dimers is dependent on the binding mode and size of the alkali cation. In the dimers, the formazanate ligands are radical dianions, as shown by X-ray absorption spectroscopy, Mössbauer spectroscopy, and analysis of metrical parameters. These experimental measures are complemented by density functional theory calculations that show the spin density on the bridging ligands.

• Item Type: Articles
• Additional Information: This work was supported by The Netherlands Organization for Scientific Research (Rubicon Postdoctoral Fellowship No. 680- 50-1517 to D.L.J.B.) and the National Institutes of Health (Grant No. GM-065313 to P.L.H.). K.L.M. thanks the A. P. Sloan Foundation and the National Science Foundation (No. CHE-1454455) for funding. XAS data were obtained at SSRL, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. The SSRL Structural Molecular Biology Program is supported by the Department of Energy’s Office of Biological and Environmental Research, and by NIH/NIGMS (including P41GM103393).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Sproules, Dr Stephen
• Authors: Broere, D. L.J., Mercado, B. Q., Bill, E., Lancaster, K. M., Sproules, S., and Holland, P. L.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Inorganic Chemistry
• Publisher: American Chemical Society
• ISSN: 0020-1669
• ISSN (Online): 1520-510X
• Published Online: 09 April 2018
• Copyright Holders: Copyright © 2018 American Chemical Society
• First Published: First published in Inorganic Chemistry 57(16):9580-9591
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher