Selected solid-state behaviour of three di-tert-butyl-substituted N-salicylideneaniline derivatives: temperature-induced phase transitions and chromic behaviour

Mason, Helen E.; Howard, Judith A.K.; Sparkes, Hazel A.

Abstract

The synthesis, single-crystal structures and chromic behaviour of three related Schiff bases, namely, (E)-2,4-di-tert-butyl-6-{[(4-fluoro­phen­yl)imino]­meth­yl}phenol, C21H26FNO, 1, (E)-2,4-di-tert-butyl-6-{[(4-chloro­phen­yl)imino]­meth­yl}phenol, C21H26ClNO, 2, and (E)-6-{[(4-bromo­phen­yl)imino]­meth­yl}-2,4-di-tert-butyl­phenol, C21H26BrNO, 3, are reported. Two polymorphs of 1 were obtained, which were found to have different photochromic properties. Schiff bases 2 and 3 were found to be isostructural and underwent a phase transition upon cooling which was attributed to the dynamic disorder in one of the tert-butyl groups resolving at low temperature. All of the structures were found to exist in the enol rather than the keto form based on the C—O(H) and imine C=N bond lengths, and contained an intra­molecular O—H⋯N hydrogen bond alongside weaker inter­molecular C—H⋯O contacts.

Citation

Mason, H. E., Howard, J. A., & Sparkes, H. A. (2021). Selected solid-state behaviour of three di-tert-butyl-substituted N-salicylideneaniline derivatives: temperature-induced phase transitions and chromic behaviour. Acta Crystallographica Section C: Structural Chemistry, 77(10), 659-667. https://doi.org/10.1107/s2053229621008780

• Journal Article Type: Article
• Acceptance Date: Aug 23, 2021
• Online Publication Date: Sep 29, 2021
• Publication Date: 2021-10
• Deposit Date: Jan 19, 2022
• Publicly Available Date: Jan 20, 2022
• Journal: Acta Crystallographica Section C Structural Chemistry
• Electronic ISSN: 2053-2296
• Publisher: International Union of Crystallography
• Peer Reviewed: Peer Reviewed
• Volume: 77
• Issue: 10
• Pages: 659-667
• DOI: https://doi.org/10.1107/s2053229621008780
• Public URL: https://durham-repository.worktribe.com/output/1219380