A Brønsted ligand molecular switch with five accessible states

Shiga, Takuya; Saiki, Ryo; Akiyama, Lisa; Kumai, Reiji; Natke, Dominik; Renz, Franz; Cameron, Jamie; Newton, Graham; Oshio, Hiroki

Abstract

A mononuclear Fe(II) complex, prepared with a Brønsted diacid ligand, H2L (H2L = 2-[5-phenyl-1H-pyrazole-3-yl] 6benzimidazole pyridine), shows switchable physical properties and was isolated in five different electronic states. The spin crossover (SCO) complex, [FeII(H2L)2](BF4)2 (1A), exhibits abrupt spin transition at T1/2 = 258 K, and treatment with base yields a deprotonated analogue [FeII(HL)2] (1B), which shows gradual SCO above 350 K. A range of ferric analogues were also characterized. [FeIII(HL)(H2L)](BF4)Cl (1C) has an S = 5/2 spin state, while the deprotonated complexes [FeIII(L)(HL)], (1D), and (TEA)[FeIII(L)2], (1E) exist in the low-spin S = 1/2 state. The electronic properties of the five complexes were fully characterized and we demonstrate in situ switching between multiple states in both solution and the solid-state. The versatility of this simple mononuclear system illustrates how proton donor/acceptor ligands can vastly increase the range of accessible states in switchable molecular devices.

Citation

Shiga, T., Saiki, R., Akiyama, L., Kumai, R., Natke, D., Renz, F., …Oshio, H. (2019). A Brønsted ligand molecular switch with five accessible states. Angewandte Chemie International Edition, 58(17), 5658-5662. https://doi.org/10.1002/anie.201900909

• Journal Article Type: Article
• Acceptance Date: Feb 4, 2019
• Online Publication Date: Feb 12, 2019
• Publication Date: Apr 16, 2019
• Deposit Date: Mar 15, 2019
• Publicly Available Date: Feb 13, 2020
• Journal: Angewandte Chemie International Edition
• Print ISSN: 1433-7851
• Electronic ISSN: 1521-3773
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 58
• Issue: 17
• Pages: 5658-5662
• DOI: https://doi.org/10.1002/anie.201900909
• Public URL: https://nottingham-repository.worktribe.com/output/1655670
• Publisher URL: https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.201900909
• Additional Information: This is the peer reviewed version of the following article: Shiga, T. , Saiki, R. , Akiyama, L. , Kumai, R. , Natke, D. , Renz, F. , Cameron, J. , Newton, G. and Oshio, H. (2019), A Brønsted ligand molecular switch with five accessible states. Angew. Chem. Int. Ed. which has been published in final form at https://doi.org/10.1002/anie.201900909. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.