Improving the mesomorphism in bispyrazolate Pd(II) metallomesogens: an efficient platform for ionic conduction

The introduction of structural asymmetry in metallomesogens is an established strategy to improve their mesomorphic behaviour in terms of lower melting temperatures and higher stability ranges of the mesophase, which is particularly important for metallomesogens that have potential application as el...

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Detalles Bibliográficos
Autores: Cuerva de Alaiz, Cristian, Cano Esquivel, María Mercedes, Schmidt, Rainer
Tipo de recurso: artículo
Fecha de publicación:2023
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/93817
Acceso en línea:https://hdl.handle.net/20.500.14352/93817
Access Level:acceso abierto
Palabra clave:538.9
Columnar mesophases
Pyrazolate ligands
Complexes
Física del estado sólido
2211 Física del Estado Sólido
Descripción
Sumario:The introduction of structural asymmetry in metallomesogens is an established strategy to improve their mesomorphic behaviour in terms of lower melting temperatures and higher stability ranges of the mesophase, which is particularly important for metallomesogens that have potential application as electrolytes that require wide operational temperature ranges. Here in this work, a novel series of unsymmetrical bis(isoquinolinylpyrazolate)palladium(ii) compounds bearing four alkyl side-chains with different lengths are described. Rectangular and hexagonal columnar mesophases were formed with low melting temperatures of 42-45 degrees C in most cases, whereas the clearing temperatures reached values up to 412 degrees C. The charge transport properties have been studied by complex impedance spectroscopy, showing that the mesophase favours proton conduction in the absence of water or humidity. The exceptional thermal stability of these species makes them promising candidates to act as a platform for ionic conduction via the nanochannels originated in the columnar mesophases. The results presented confirm that introducing structural asymmetry in the Pd(ii) metallomesogens studied is a valid strategy to enhance the liquid crystalline properties, which opens new ways to develop water-free electrolytes based on unsymmetrical bis(isoquinolinylpyrazolate) Pd(ii) compounds for potential applications such as proton exchange membranes (PEMs).