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Solving the 170‐Year‐Old Mystery About Red‐Violet and Blue Transient Intermediates in the Gmelin Reaction
Author(s) -
Gao Yin,
Toubaei Abouzar,
Kong Xianqi,
Wu Gang
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201503353
Subject(s) - transient (computer programming) , ultra violet , blue light , chemistry , photochemistry , computer science , physics , optics , optoelectronics , operating system
The Gmelin reaction between nitroprusside and sulfides in aqueous solution is known to produce two transient intermediates with distinct colors: an initial red‐violet intermediate that subsequently converts into a blue intermediate. In this work, we use a combination of multinuclear ( 17 O, 15 N, 13 C) NMR, UV/Vis, IR spectroscopic techniques and quantum chemical computation to show unequivocally that the red‐violet intermediate is [Fe(CN) 5 N(O)S] 4− and the blue intermediate is [Fe(CN) 5 N(O)SS)] 4− . While the formation of [Fe(CN) 5 N(O)S] 4− has long been postulated in the literature, this study provides the most direct proof of its structure. In contrast, [Fe(CN) 5 N(O)SS)] 4− represents the first example of any metal coordination complex containing a perthionitro ligand. The new reaction pathways found in this study not only provide clues for the mode of action of nitroprusside for its pharmacological activity, but also have broader implications to the biological role of H 2 S, potential reactions between H 2 S and nitric oxide donor compounds, and the possible biological function of polysulfides.