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The Effect of Zn II Coordination on the Addition of 2‐(Aminomethyl)benzimidazole to Acrylonitrile
Author(s) -
FalcónLeón Martha P.,
TapiaBenavides Antonio R.,
Tlahuext Hugo,
GalánVidal Carlos,
SuarezCastillo Oscar R.,
Tlahuextl Margarita
Publication year - 2014
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201402346
Subject(s) - chemistry , acrylonitrile , benzimidazole , medicinal chemistry , molecule , aqueous solution , amine gas treating , zinc , nuclear magnetic resonance spectroscopy , chelation , inorganic chemistry , stereochemistry , organic chemistry , copolymer , polymer
The effects of N→Zn coordination, solvent, and pH on the aza‐addition reaction between 2‐(aminomethyl)benzimidazole (HL) and acrylonitrile were studied. In the absence of Zn II ion, the aza‐addition reactions between HL and acrylonitrile (in aqueous media) depended on pH and were not selective. The mono‐addition compound {3‐[(1 H ‐benzimidazol‐2‐ylmethyl)amino]propanenitrile} was always obtained in a greater proportion than the di‐addition products [3,3′‐[(1 H ‐benzimidazol‐2‐ylmethyl)imino]dipropanenitrile and 3‐(2‐{[(2‐cyanoethyl)amino]methyl}‐1 H ‐benzimidazol‐1‐yl)propanenitrile]. Acrylonitrile selectively reacted at the amine group in the [ZnCl 3 (H 2 L)] and [ZnCl 2 (HL)] complexes in aqueous solutions. Moreover, [ZnCl(HL) 2 ]Cl and [Zn(H 2 O) 2 (HL) 2 ]Cl 2 complexes yielded mixtures of mono‐ and di‐addition products. In contrast, Zn complexes formed with HL did not react with acrylonitrile in solution in DMSO. The synthesis of mono‐ and di‐addition compounds was studied by 1 H and 13 C NMR spectroscopy and X‐ray diffraction crystallography. Quantum theory of atoms in molecules (QTAIM) computations were used to demonstrate the probable presence of a mono‐addition chelate complex.