Issue 42, 2015

Hydrogels formed from Fmoc amino acids


A number of Fmoc amino acids can be effective low molecular weight hydrogelators. The type of gel formed depends on the amino acid used and, in the case of FmocF, the final pH of the system. The single crystal structure of two of the gelators (FmocF and FmocY) have been determined and the data compared to the fibre X-ray diffraction data. FmocF, which forms metastable gels, crystallises easily and the data for the fibre phase and crystal phase are relatively similar. For FmocF, the fibre axis in b is consistent with the hydrogen bonding repeat distances and the diffraction pattern calculated from the single crystal structure is a good match with the experimental fibre X-ray diffraction data. On the other hand, there are significant differences between the crystalline phase determined and the fibre phase for FmocY. The packing of FmocY within the crystal structure is created by interactions between the planar Fmoc groups, whilst it is clear that hydrogen bonding drives the self-assembly into fibrillar structures within the gels. This shows that understanding the packing in gel phase by analogy to isolated crystal structures has the potential to lead to erroneous conclusions.

Graphical abstract: Hydrogels formed from Fmoc amino acids

Supplementary files

Article information

Article type
23 Apr 2015
11 Jun 2015
First published
11 Jun 2015
This article is Open Access
Creative Commons BY license

CrystEngComm, 2015,17, 8047-8057

Author version available

Hydrogels formed from Fmoc amino acids

E. R. Draper, K. L. Morris, M. A. Little, J. Raeburn, C. Colquhoun, E. R. Cross, Tom. O. McDonald, L. C. Serpell and D. J. Adams, CrystEngComm, 2015, 17, 8047 DOI: 10.1039/C5CE00801H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity