Probing Hydrogen Bonding Interactions to Iron‐Oxido/Hydroxido Units by 57Fe Nuclear Resonance Vibrational Spectroscopy. Issue 49 (14th November 2018)

• Record Type: Journal Article
• Authors: Weitz, Andrew C.; Hill, Ethan A.; Oswald, Victoria F.; Bominaar, Emile L.; Borovik, Andrew S.; Hendrich, Michael P.; Guo, Yisong
• Is Part Of: Angewandte Chemie international edition. Volume 57:Issue 49(2018)
• Page Start: 16010
• Page End: 16014
• Publication Date: 2018-11-14
• Subjects: 57Fe nuclear resonance vibrational spectroscopy -- C−H activation -- hydrogen bonds -- non-heme iron-oxo/hydroxo complexes -- secondary coordination sphere; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201810227
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Hydrogen bonds (H‐bonds) have been shown to modulate the chemical reactivities of iron centers in iron‐containing dioxygen‐activating enzymes and model complexes. However, few examples are available that investigate how systematic changes in intramolecular H‐bonds within the secondary coordination sphere influence specific properties of iron intermediates, such as iron‐oxido/hydroxido species. Here, we used 57 Fe nuclear resonance vibrational spectroscopy (NRVS) to probe the Fe‐O/OH vibrations in a series of Fe III ‐hydroxido and Fe IV/III ‐oxido complexes with varying H‐bonding networks but having similar trigonal bipyramidal primary coordination spheres. The data show that even subtle changes in the H‐bonds to the Fe‐O/OH units result in significant changes in their vibrational frequencies, thus demonstrating the utility of NRVS in studying the effect of the secondary coordination sphere to the reactivities of iron complexes. Abstract : Hydrogen bond strength to iron(III)‐oxido/hydroxido (Fe III −O/OH) units in nonheme iron complexes is revealed by 57 Fe nuclear resonance vibrational spectroscopy, thus providing a methodology to elucidate the influence of hydrogen bonds in the secondary coordination sphere to the stability of Fe III −O/OH units, and potentially connecting it to the reactivities of Fe IV −O units.