Miniatura

Fitxers

678271.pdf (8.76 MB)

Tipus de document

Article

Versió

Versió acceptada

Data de publicació

2017-03-01

Tots els drets reservats

Si us plau utilitzeu sempre aquest identificador per citar o enllaçar aquest document: https://hdl.handle.net/2445/154513

Bistability in organic magnetic materials: a comparative study of the key differences between hysteretic and non-hysteretic spin transitions in dithiazolyl radicals

Títol de la revista

Autors

Director/Tutor

ISSN de la revista

Títol del volum

Recurs relacionat

https://doi.org/10.1002/chem.201700021

Resum

Dithiazolyl (DTA)- based radicals have furnished many examples of organic spin- transition materials, some of them occurring with hysteresis and some others without. Herein, we present a combined computational and experimental study aimed at deciphering the factors controlling the existence or absence of hysteresis by comparing the phase transitions of 4- cyanobenzo- 1,3,2- dithiazolyl and 1,3,5trithia- 2,4,6- triazapentalenyl radicals, which are prototypical examples of non- bistable and bistable spin transitions, respectively. Both materials present low- temperature diamagnetic and high- temperature paramagnetic structures, characterized by dimerized (center dot center dot center dot A-A center dot center dot center dot A-A center dot center dot center dot) n and regular (center dot center dot center dot A center dot center dot center dot A center dot center dot center dot A center dot center dot center dot A center dot center dot center dot) n pi- stacks of radicals, respectively. We show that the regular pi-stacks are not potential energy minima but average structures arising from a dynamic inter-conversion between two degenerate dimerized configurations: (center dot center dot center dot A-A center dot center dot center dot A-A center dot center dot center dot)n <->(-A center dot center dot center dot A-A center dot center dot center dot A-)n. The emergence of this intrastack dynamics upon heating gives rise to a second-order phase transition that is responsible for the change in the dominant magnetic interactions of the system. This suggests that the promotion of a (center dot center dot center dot A-A center dot center dot center dot A-A center dot center dot center dot)n <->(-A center dot center dot center dot A-A center dot center dot center dot A-) n dynamics is a general mechanism for triggering spin transitions in DTA-based materials. Yet, this intra-stack dynamics does not suffice to generate bistability, which also requires a rearrangement of the intermolecular bonds between the pstacks via a first-order phase transition.

Matèries

Transformacions de fase (Física estadística), Radicals (Química)

Matèries (anglès)

Phase transformations (Statistical physics), Radicals (Chemistry)

Citació

Col·leccions

Articles publicats en revistes (Ciència dels Materials i Química Física)

Citació

VELA LLAUSÍ, Sergi, REARDON, Michael b., JAKOBSCHE, Charles e., TURNBULL, Mark m., RIBAS ARIÑO, Jordi, NOVOA VIDE, Juan j.. Bistability in organic magnetic materials: a comparative study of the key differences between hysteretic and non-hysteretic spin transitions in dithiazolyl radicals. _Chemistry-A European Journal_. 2017. Vol. 23, núm. 14, pàgs. 3479-3489. [consulta: 27 de gener de 2026]. ISSN: 0947-6539. [Disponible a: https://hdl.handle.net/2445/154513]

Exportar metadades

JSON - METS

Compartir registre