Multifunctional Pt(ii) metallomesogens exhibiting luminescence and proton conductivity in the mesophase near room temperature

Abstract

New asymmetrical pyridine- and isoquinoline-functionalized bis(pyrazolate) Pt(II) metallomesogens have been engineered and designed to exhibit multifunctional properties in terms of mesomorphism, photoluminescence and ionic conductivity near room temperature. The molecules are self-assembled in hexagonal columnar mesophases via Pt⋯Pt interactions, which generates a strong orange-red emission as a result of the formation of triplet metal–metal-to-ligand charge-transfer (³MMLCT) excited states. Concomitantly, the hexagonal columnar mesophases open continuous nanochannels that have been used for proton conduction over a wide range of temperatures. It is also noteworthy that the luminescence typically decreases with temperature, whereas the ionic conductivity increases to values of the order of 10⁻⁵ Ω⁻¹ cm⁻¹ at ca. 300 °C in the mesophase.