Squaramide-Based Self-Associating Amphiphiles for Anion Recognition

Lokesh K Kumawat; Conor Wynne; Emanuele Cappello; Peter Fisher; Luke E Brennan; Alessandro Strofaldi; Jennifer J McManus; Chris S Hawes; Katrina A Jolliffe; Thorfinnur Gunnlaugsson; Robert B P Elmes

doi:10.1002/cplu.202100275

Squaramide-Based Self-Associating Amphiphiles for Anion Recognition

Chempluschem. 2021 Aug;86(8):1058-1068. doi: 10.1002/cplu.202100275.

Authors

Lokesh K Kumawat¹, Conor Wynne^{1

2}, Emanuele Cappello³, Peter Fisher¹, Luke E Brennan¹, Alessandro Strofaldi¹, Jennifer J McManus^{1

4

2}, Chris S Hawes⁵, Katrina A Jolliffe⁶, Thorfinnur Gunnlaugsson^{3

2}, Robert B P Elmes^{1

7

2}

Affiliations

¹ Department of Chemistry, Maynooth University, National University of Ireland, Maynooth, Co. Kildare, Ireland.
² Synthesis and Solid State Pharmaceutical Centre (SSPC), Ireland.
³ School of Chemistry, Trinity Biomedical Sciences Institute (TBSI), Trinity College Dublin, The University of Dublin, Dublin 2, Ireland.
⁴ HH Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, United Kingdom.
⁵ School of Chemical and Physical Sciences, Keele University, Keele, ST5 5BG, United Kingdom.
⁶ School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia.
⁷ Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Co. Kildare, Ireland.

Abstract

The synthesis and characterisation of two novel self-assembled amphiphiles (SSAs) SQS-1 and SQS-2 are reported. Both compounds, based on the squaramide motif, were fully soluble in a range of solvents and were shown to undergo self-assembly through a range of physical techniques. Self-assembly was shown to favour the formation of crystalline domains on the nanoscale but also fibrillar film formation, as suggested by SEM analysis. Moreover, both SQS-1 and SQS-2 were capable of anion recognition in DMSO solution as demonstrated using ¹ H NMR and UV/Vis absorption spectroscopy, but displayed lower binding affinities for various anions when compared against other squaramide based receptors. In more competitive solvent mixtures SQS-1 gave rise to a colourimetric response in the presence of HPO₄^2- that was clearly visible to the naked eye. We anticipate that the observed response is due to the basic nature of the HPO₄^2- anion when compared against other biologically relevant anions.

Keywords: anion recognition; colorimetric sensors; self-assembly; squaramides; supramolecular chemistry.

Publication types

Research Support, Non-U.S. Gov't

Abstract

Publication types

Grants and funding