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Hydrogen‐Bond Cooperativity in Formamide 2 –Water: A Model for Water‐Mediated Interactions
Author(s) -
Blanco Susana,
Pinacho Pablo,
López Juan Carlos
Publication year - 2016
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.201603319
Subject(s) - formamide , hydrogen bond , chemistry , rotational spectroscopy , solvation , crystallography , molecule , adduct , amide , cooperativity , computational chemistry , organic chemistry , biochemistry
The rotational spectrum of formamide 2 –H 2 O formed in a supersonic jet has been characterized by Fourier‐transform microwave spectroscopy. This adduct provides a simple model of water‐mediated interaction involving the amide linkages, as occur in protein folding or amide‐association processes, showing the interplay between self‐association and solvation. Mono‐substituted 13 C, 15 N, 18 O, and 2 H isotopologues have been observed and their data used to investigate the structure. The adduct forms an almost planar three‐body sequential cycle. The two formamide molecules link on one side through an N−H⋅⋅⋅O hydrogen bond and on the other side through a water‐mediated interaction with the formation of C=O⋅⋅⋅H−O and O⋅⋅⋅H−N hydrogen bonds. The analysis of the quadrupole coupling effects of two 14 N‐nuclei reveals the subtle inductive forces associated to cooperative hydrogen bonding. These forces are involved in the changes in the C=O and C−N bond lengths with respect to pure formamide.