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Title: A Copper(II)‐Nitrite Complex Hydrogen‐Bonded to a Protonated Amine in the Second‐Coordination‐Sphere
Abstract Nitrous acid (HONO) plays pivotal roles in various metal‐free as well as metal‐mediated routes relevant to biogeochemistry, atmospheric chemistry, and mammalian physiology. While the metastable nature of HONO hinders the detailed investigations into its reactivity at a transition metal site, this report herein utilizes a heteroditopic copper(II) cryptate [oC]CuIIfeaturing a proton‐responsive second‐coordination‐sphere located at a suitable distance from a [CuII](ONO) core, thereby enabling isolation of a [CuII](κ1‐ONO⋅⋅⋅H+) complex (2H‐NO2). A set of complementary analytical studies (UV‐vis,14N/15N FTIR,15N NMR, HRMS, EPR, and CHN) on2H‐NO2and its15N‐isotopomer (2H‐15NO2) reveals the formulation of2H‐NO2as {[oCH]CuII(κ1‐ONO)}(ClO4)2. Non‐covalent interaction index (NCI) based on reduced density gradient (RDG) analysis on {[oCH]CuII(κ1‐ONO)}2+discloses a H‐bonding interaction between the apical 3° ammonium site and the nitrite anion bound to the copper(II) site. The FTIR spectra of [CuII](κ1‐ONO⋅⋅⋅H+) species (2H‐NO2) shows a shift of ammonium NH vibrational feature to a lower wavenumber due to the H‐bonding interaction with nitrite. The reactivity profile of [CuII](κ1‐ONO⋅⋅⋅H+) species (2H‐NO2) towards anaerobic nitration of substituted phenol (2,4‐DTBP) is distinctly different relative to that of the closely related tripodal [CuII]‐nitrite complexes (1‐NO2/3‐NO2/4‐NO2).  more » « less
Award ID(s):
1847926
PAR ID:
10367578
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
European Journal of Inorganic Chemistry
Volume:
2022
Issue:
15
ISSN:
1434-1948
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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