Issue 44, 2021

Packing polymorphism, odd–even alternation and thermotropic phase transitions in N-,O-diacylethanolamines with varying N-acyl chains. A combined experimental and computational study

Abstract

N-,O-Diacylethanolamines (DAEs) are derived by simple esterification of bioactive N-acylethanolamines, which are present in plant and animal tissues. In this study, two homologous series of DAEs, namely N-acyl (n = 8–15), O-palmitoylethanolamines (Nn–O16s) and N-acyl (n = 8–14), O-pentadecanoylethanolamines (Nn–O15s) were synthesized and characterized with respect to thermotropic phase transitions, crystal structures and intermolecular interactions. In addition, computational studies were performed to get a molecular level insight into the role of different factors in selective polymorphism in Nn–O16s and Nn–O15s. Differential scanning calorimetric studies revealed that dry Nn–O16s exhibit odd–even alternation in their calorimetric properties, which is absent in Nn–O15s. The 3-dimensional structures of three Nn–O16s (n = 12–14) and two Nn–O15s (n = 12, 14) have been determined by single-crystal X-ray diffraction. Analysis of the molecular packing in these crystals showed the presence of two packing polymorphs (α and β) in the crystal lattice of Nn–O16s, whereas only the β polymorph was observed in the Nn–O15s. Further, intermolecular hydrogen bonding interactions (N–H⋯O and C–H⋯O) and dispersion interactions among acyl chains have been found to stabilize the molecular packing observed in the crystal lattice. Molecular dynamics simulations show that the β polymorph is slightly energetically preferred over the α polymorph in all the systems due to favorable packing of terminal methyl groups at the interlayers. These findings are relevant for understanding the interactions of the DAEs with membrane lipids and proteins.

Graphical abstract: Packing polymorphism, odd–even alternation and thermotropic phase transitions in N-,O-diacylethanolamines with varying N-acyl chains. A combined experimental and computational study

Supplementary files

Article information

Article type
Paper
Submitted
11 Aug 2021
Accepted
20 Oct 2021
First published
20 Oct 2021

Phys. Chem. Chem. Phys., 2021,23, 25264-25277

Packing polymorphism, odd–even alternation and thermotropic phase transitions in N-,O-diacylethanolamines with varying N-acyl chains. A combined experimental and computational study

S. T. Reddy, D. Sivaramakrishna, K. Mamatha, M. Sharma and M. J. Swamy, Phys. Chem. Chem. Phys., 2021, 23, 25264 DOI: 10.1039/D1CP03704H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements