The effect of polarization on multiple hydrogen‐bond formation in models of self‐assembling materials

Abstract

We report density functional theory calculations at the B3LYP/D95(d,p) level on several different cyclic H-bonding dimers, where the monomers of each are connected by a pair of N-H···O=C H-bonding interactions, and the H-bonding donors and acceptors on each monomer are separated by polarizable spacers. Depending on the structures, the individual H-bonds vary in strength (enthalpy) by over a factor of four, from 2.41 to 10.99 kcal/mol. We attribute most of the variation in interaction energies to differences in the extent of polarization due to each of the H-bonds, which can either combine constructively or destructively. The dipole-dipole interactions between the pair of H-bonds also contribute somewhat to the relative stabilities. The relevance of these results to the design of self-assembling materials is discussed.

DFT Study on Characterization of Hydrogen Bonds in the Hydrates of MgSO4

“…22 ■ RESULTS AND DISCUSSION Energies of hydration in the Mg 2+ ion are in the range of 30−80 kcal/mol, 14 and energy exchange in the formation of a strong hydrogen bond, X−H•••Y, is on the order of 10−17 kcal/ mol. 23,24 This suggests that systems involving large numbers of hydrogen bonds can possibly disturb the Mg−O bond in Mg 2+containing salts. This has been investigated in the following sections where we discuss optimized structures of MgSO 4 •xH 2 O molecules.…”

Insights into a highly conserved network of hydrogen bonds in the agonist binding site of nicotinic acetylcholine receptors: A structural and theoretical study

“…Multiple intermolecular interactions such as hydrogen bonds between molecules or molecular fragments in a macromolecule (e.g., amide bonds in proteins) lead to cooperative stabilization of the resulting noncovalent complex . In the structural motif investigated in this study, the hydrogen‐bond interaction between the main chain NH of His145 and the hydroxyl group of Ser142 (probed by the d 5 distance in the previous paragraph) has probably a significant effect on the hydrogen‐bond interaction between the hydroxyl group of Ser142 and the carboxylate group of Asp85, one of the main component of the hydrogen‐bond network.…”

Density Functional Theory Study of β-Hairpins in Antiparallel β-Sheets, a New Classification Based upon H-Bond Topology

“…Larger models of β-sheets have energies (corrected for differences in cooperativity) that differ by the same amount depending on whether they contain one more large than small ring or the reverse . Other isomeric cyclic H-bonding structures exhibit similar characteristics . From the foregoing, we expect the C 10 H-bond would have a Δ H of approximately −2.5 (half of the stabilization of the small ring by its two H-bonds) if in an isolated system.…”

“…2 Other isomeric cyclic H-bonding structures exhibit similar characteristics. 4 From the foregoing, we expect the C 10 H-bond would have ΔH~ −2.5 (half of the stabilization of the small ring by its two H-bonds) if in an isolated system. Certainly, the C 10 H-bond should be substantially weaker than the C 14 H-bond, which is part of a large ring.…”