Issue 34, 2021

Epimers with distinct mechanical behaviours

Abstract

This study highlights the impact of relative stereochemistry in epimer compounds on their mechanical properties; the crystals of one series of esters are ductile and deform plastically upon bending, whereas the other series are all brittle. Nanoindentation studies show that the hardness, H, and elastic moduli, E, of the brittle crystals are substantially larger than those of the ductile ones. For the brittle crystals, the H values range from 153(10) to 293(37) MPa and E from 2.85(0.33) to 9.10(0.51) GPa, whereas for the ductile crystals, the H values range from 76(2) to 125(11) MPa and E from 1.40(0.36) and 2.75(0.06) GPa. These are rationalized by recourse to the distinct crystal structural features, especially in terms of interdigitation in the molecular planes in the brittle crystals and slip planes in the ductile crystals. The indentation fracture toughness, Kc, values of the (2′S) crystals are higher than those typically reported for molecular crystals, due to the corrugated nature of their crystal packing which enhances the crack tortuosity. The Kc values are in the range 0.215 (0.08) to 0.278 (0.06) MPa m½ and the brittleness index values are in the range 711(19) to 1053(50) m−½.

Graphical abstract: Epimers with distinct mechanical behaviours

Supplementary files

Article information

Article type
Paper
Submitted
25 nov. 2020
Accepted
05 mar. 2021
First published
05 mar. 2021

CrystEngComm, 2021,23, 5848-5855

Epimers with distinct mechanical behaviours

U. B. R. Khandavilli, A. M. Buckley, A. R. Maguire, M. S. R. N. Kiran, U. Ramamurty and S. E. Lawrence, CrystEngComm, 2021, 23, 5848 DOI: 10.1039/D0CE01723J

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