Theoretical investigations into the intermolecular hydrogen-bonding interactions of N-(hydroxymethyl)acetamide dimers

Abstract

The structures of the N-(hydroxymethyl)acetamide (model molecule of ceramide) dimers have been fully optimized at B3LYP/6-311++G** level. The intermolecular hydrogen bonding interaction energies have been calculated using the B3LYP/6-311++G**, B3LYP/6-311++G(2df,2p), MP2(full)/6-311++G** and MP2(full)/6-311++G(2df,2p) methods, respectively. The results show that the O-H···O, N-H···O, O-H···N, and C-H···O hydrogen bonding interactions could exist in N-(hydroxymethyl)acetamide dimers, and the O-H···O, N-H···O, and O-H···N hydrogen bonding interactions could be stronger than C-H···O. The three-dimensional network structure formed by ceramide molecules through intermolecular hydrogen bonding interactions may be the main reason why the stratum corneum of skin could prevent foreign substances from entering our body, as is in accordance with the experimental results. The stability of hydrogen-bonding interactions follow the order of (a) > (b) ≈ (c) > (d) > (e) ≈ (f) > (g) > (h). The analyses of the energy decomposition, frequency, atoms in molecules (AIM), natural bond orbital (NBO), and electron density shift are used to further reveal the nature of the complex formation. In the range of 263.0-328.0 K, the complex is formed via an exothermic reaction, and the solvent with lower temperature and dielectric constant is favorable to this process. Graphical abstract The structures and the O-H···O=C, N-H···O=C and C-H···O=C H-bonding interactions in the N-(hydroxymethyl)acetamide (model molecule of ceramide) dimers were investigated using the B3LYP and MP2(full) methods.

Methyl Groups as Hydrogen Bond Acceptors via Their sp3Carbon Atoms

“…On the other hand, the H-bond donor, i.e., the hydrogen atom, shows a blue region that indicates a decrease of the electron density. These pictures are very similar to those found in previous EDS studies of hydrogen bonds, both intra- and intermolecular. , …”

“…These pictures are very similar to those found in previous EDS studies of hydrogen bonds, both intra- 40 and intermolecular. 41,42 Only the H atoms involved in the CH 3 •••HN interaction were optimized from the crystallographic coordinates. Natural bond orbital (NBO) analyses have been carried out to disclose the dominant orbital interactions involved in the studied hydrogen bonds.…”

Very Long Chain Lipids Favor the Formation of a Homogeneous Phase in Stratum Corneum Model Membranes

“…The results clearly establish the key role of lipid chain length for the formation of a homogeneous lipid matrix. Intermolecular interactions between the components of SC lipid matrix include H-bonding at the head group level as well as van der Waals interactions at the chain level. − Experimental and theoretical studies have shown the importance of H bonds in the structure of SC lipids. − Extensive phase separations were observed in the CerNS16/FFA16/Chol mixture, a mixture for which the hydrophobic matching between the components is optimal. This finding suggests that interfacial intermolecular interactions are a driving factor of this phase separation.…”

“…This finding suggests that interfacial intermolecular interactions are a driving factor of this phase separation. The strength of Cer–Cer H-bonds has been estimated, from ab initio and density functional theory (DFT) methods, to vary between 20 and 62 kJ/mol; these should contribute to phase separations if they are more stable than those between ceramide and FFA and/or cholesterol. Actually, molecular dynamics simulations of CerNS24/FFA24/Chol mixtures showed that H-bonding between Cer–Cer pairs is dominating, if the H-bond involving water are not considered. − In these studies, the lipid distribution was found to be homogeneous, except that molecular clusters involving about five molecules with a slight enrichment in CerNS were reported in one study .…”

A Water-Lean Triazole Ionic Liquid Biphasic Solvent for Energy-Efficient CO2 Capture Through Reversible Polarity and Intermolecular Hydrogen Bonding

“…However, high energy consumption of organic amine solvents is the main hindrance of large-scale applications for CO 2 capture due to high CO 2 reaction enthalpy with amines and large amounts of water vaporization. For example, the energy consumption of MEA aqueous solution regeneration for CO 2 capture from industrial flue gas was 3.50–4.20 GJ/ton CO 2 . − Therefore, it has become a great challenge to develop novel solvents with low volatility, high absorption performance, and low energy consumption. , …”