Synthesis, Spectroscopic Characterization, Mesogenic Properties and Thermal Studies of Six New Iridium(V) Long Carbon Chain Sulphate Chloride Complexes

Abstract

Six new iridium (V) complexes with long carbon chain sulphate chloride ligands, [Ir(SDS)₂Cl₂]Cl (1), [Ir(Myristyl sulphate)₂Cl₂]Cl (2), [Ir(Cetyl sulphate)₂Cl₂]Cl (3), [Ir(Stearyl sulphate)₂Cl₂]Cl (4), [Ir(Arachidyl sulphate)₂Cl₂]Cl (5) and [Ir(Behenyl sulphate)₂Cl₂]Cl (6), have been synthesized and characterized using various techniques, including IR, NMR, and mass spectrometry. The IR and NMR spectra confirmed the presence of alkyl sulphate and chloride ligands, while electronic absorption spectra and ionic conductivity revealed a low-spin d⁵ configuration for the Ir(V) complexes. Thermal analysis revealed that the complexes exhibit liquid crystal properties, with melting points and decomposition temperatures increasing with alkyl chain length. The complexes showed ionic conductivity, with conductivity values ranging from 13.67 to 18.68 Ω⁻¹ cm² mol⁻¹, indicating 1:1 electrolyte behaviour. Magnetic moment measurements confirmed a low-spin state for Ir⁵⁺. The complexes' thermal stability increased with alkyl chain length, with decomposition temperatures ranging from 250 °C to 300 °C. This study highlights the potential of these iridium(V) complexes in applications such as optoelectronics and catalysis, and demonstrates the importance of alkyl chain length in determining their thermal properties.