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Selective Phase Transfer Reagents (OxP‐crowns) for Chromogenic Detection of Nitrates Especially Ammonium Nitrate
Author(s) -
Chahal Mandeep K.,
Payne Daniel T.,
Labuta Jan,
Karr Paul A.,
D'Souza Francis,
Ariga Katsuhiko,
Hill Jonathan P.
Publication year - 2020
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.202003166
Subject(s) - chromogenic , chemistry , ammonium , deprotonation , aqueous two phase system , aqueous solution , inorganic chemistry , ammonium nitrate , selectivity , nitrate , reagent , ion , organic chemistry , chromatography , catalysis
Nitrogen and phosphorus‐containing ions such as ammonium, nitrates and phosphates are anthropogenic pollutants while ammonium nitrate may be diverted for nefarious purposes in improvised explosive devices. Crown ether‐oxoporphyrinogen conjugates ( OxP ‐crowns) are used to selectively detect nitrates, especially their ion pairs with K + and NH 4 + , based on ion pair complexation of OxP ‐crowns under phase transfer conditions. The presence of phosphate and carbonate lead to deprotonation of OxP ‐crowns. OxP‐1N18C6 is capable of extracting ion pairs with nitrate from aqueous phase leading to a selective chromogenic response. Deprotonation of the OxP moiety leads to [ OxP − ] ‐1N18C6 [K + ] and is promoted by crown ether selective cation binding coupled with hydration of basic oxoanions, which are constrained to remain in the aqueous phase. This work illustrates the utility of molecular design to exploit partitioning and ion hydration effects establishing the selectivity of the chromogenic response.