Ionic Liquids-Cobalt(II) Thermochromic Complexes: How the Structure Tunability Affects "self-Contained" Systems

Billeci, Floriana; Gunaratne, H. Q.Nimal; Licence, Peter; Seddon, Kenneth R.; Plechkova, Natalia V.; D'Anna, Francesca

Abstract

With the aim of obtaining thermochromic systems with potential applications in solar energy storage, we evaluated the behavior of some sugar-based ionic liquids (ILs)-Co(NTf2)2 complexes, in IL solution, as a function of temperature. Different structural changes on the cation, the nature of the anion, and the nature of the IL used as the solvent were considered. The analysis of the above factors was carried out through a combined approach of different techniques, that is, variable temperature UV-vis and NMR spectroscopies, conductivity, and thermal gravimetric analysis. The thermochromic systems were analyzed both as solutions and as thin films, and the data collected highlight the defining role played by both the cation structure and the solvent nature in determining their performance. Most of the investigated systems show a chromogenic transition from pink to blue, occurring in a temperature range suitable for practical applications (40-60 °C). Interestingly, when embedded in a polymeric matrix, thin films with high recyclability and long life are also described.

• Journal Article Type: Article
• Acceptance Date: Mar 10, 2021
• Online Publication Date: Mar 10, 2021
• Publication Date: Mar 22, 2021
• Deposit Date: Apr 23, 2021
• Publicly Available Date: Mar 11, 2022
• Journal: ACS Sustainable Chemistry and Engineering
• Electronic ISSN: 2168-0485
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 9
• Issue: 11
• Pages: 4064-4075
• DOI: https://doi.org/10.1021/acssuschemeng.0c08586
• Public URL: https://nottingham-repository.worktribe.com/output/5394750
• Publisher URL: https://pubs.acs.org/doi/10.1021/acssuschemeng.0c08586
• Additional Information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Sustainable Chemistry and Engineering, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acssuschemeng.0c08586.