Issue 38, 2016

1,2,4-Triazole-based molecular switches: crystal structures, Hirshfeld surface analysis and optical properties

Abstract

We have studied a series of eight closely related N-salicylidene-4-amino-1,2,4-triazole molecules 1–8, obtained by condensation of the corresponding aldehyde with 4-amino-4H-1,2,4-triazole. 1H NMR spectroscopy in solution revealed the presence of a single structure at least in DMSO-d6. According to single-crystal X-ray diffraction, it was established that the crystal structures of 5–8 each are stabilized by a linear intramolecular hydrogen bond of the O–H⋯N type, formed between the o-OH hydrogen atom of the phenolic ring and the imine nitrogen atom. The same o-OH function in the crystal structures of 1–4 was found to be involved in the intermolecular hydrogen bonds with one of the triazole nitrogen atoms of the adjacent molecule. The overall geometry of each molecule in the structures of 1–8 was found to be almost planar or slightly deviated from planarity. Hirshfeld surface analysis showed that the structures of all compounds are mainly characterized by H⋯H, H⋯C, H⋯N and H⋯O contacts but some contribution from C⋯C and C⋯N contacts is also clearly observed. Diffuse reflectance spectroscopy reveals the exclusive presence of the enol form in the solid state at room temperature for 1–6 and 8, while a mixture of dominant enol and cis-keto forms were found for 7. All the studied molecules 1–8 were not photoswitchable, while 7 was found to be thermochromic from coloured to colourless upon cooling.

Graphical abstract: 1,2,4-Triazole-based molecular switches: crystal structures, Hirshfeld surface analysis and optical properties

Supplementary files

Article information

Article type
Paper
Submitted
03 apr 2016
Accepted
20 mei 2016
First published
06 jun 2016

CrystEngComm, 2016,18, 7284-7296

1,2,4-Triazole-based molecular switches: crystal structures, Hirshfeld surface analysis and optical properties

D. A. Safin, K. Robeyns and Y. Garcia, CrystEngComm, 2016, 18, 7284 DOI: 10.1039/C6CE00749J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements