Hydrogen‐Bond Cooperativity in Formamide2–Water: A Model for Water‐Mediated Interactions |
| |
Authors: | Prof. Susana Blanco Pablo Pinacho Prof. Juan Carlos López |
| |
Affiliation: | Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, Valladolid, Spain |
| |
Abstract: | The rotational spectrum of formamide2–H2O 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 13C, 15N, 18O, and 2H 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 14N‐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. |
| |
Keywords: | cooperative effects hydrogen bonds formamide rotational spectroscopy water-mediated interactions |
|
|