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Acidity and Hydrogen Exchange Dynamics of Iron(II)‐Bound Nitroxyl in Aqueous Solution
Author(s) -
Gao Yin,
Toubaei Abouzar,
Kong Xianqi,
Wu Gang
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201407018
Subject(s) - aqueous solution , chemistry , nitroxyl , hydrogen , bound water , inorganic chemistry , polymer chemistry , organic chemistry , molecule
Nitroxyl‐iron(II) (HNO‐Fe II ) complexes are often unstable in aqueous solution, thus making them very difficult to study. Consequently, many fundamental chemical properties of Fe II ‐bound HNO have remained unknown. Using a comprehensive multinuclear ( 1 H, 15 N, 17 O) NMR approach, the acidity of the Fe II ‐bound HNO in [Fe(CN) 5 (HNO)] 3− was investigated and its p K a value was determined to be greater than 11. Additionally, HNO undergoes rapid hydrogen exchange with water in aqueous solution and this exchange process is catalyzed by both acid and base. The hydrogen exchange dynamics for the Fe II ‐bound HNO have been characterized and the obtained benchmark values, when combined with the literature data on proteins, reveal that the rate of hydrogen exchange for the Fe II ‐bound HNO in the interior of globin proteins is reduced by a factor of 10 6 .