Luminescent Iridium(III) Complex with Alkoxy-Functionalised 2-Phenylpyridine Ligands: Synthesis, Spectroscopic and Photophysical Studies

Cyclometalated iridium(III) complexes have garnered considerable interest owing to their exceptional photophysical properties and broad applicability in luminescence-based technologies.This work describes the preparation, spectroscopic analysis, and photophysical characterisation of a new emissive iridium(III) complex, [Ir(bFppy)₂(eFppy)], incorporating the ligands 2-(2butoxy-4-fluorophenyl)pyridine (bFppy) and 2-(2-ethoxy-4-fluorophenyl)pyridine (eFppy).The structure identity of the complex was confirmed by ¹H NMR, ¹³C NMR, and FTIR spectroscopic techniques.In the ¹H NMR spectrum, aliphatic proton signals were observed between δ 1.00-4.09ppm, corresponding to the ethyl and butyl chain protons, while signals in the δ 5.99-8.81ppm region were attributed to aromatic protons of the phenylpyridine frameworks.A total of 43 carbon resonances were resolved in the ¹³C NMR spectrum, in complete accordance with the number of carbon atoms anticipated from the proposed structure.Complementary FTIR data supported these assignments through the observation of C-H, C=C, and C=N stretching bands characteristic of the complex.UV-Vis spectroscopy identified π-π* intraligand transitions in the ultraviolet region and MLCT transitions extending into the visible range.Steady-state emission measurements revealed that the complex produces intense green phosphorescence in dichloromethane solution at ambient temperature, with an emission maximum at λem = 502 nm, indicative of an emissive pathway dominated by ³MLCT character.The efficient triplet-state emission exhibited by this complex highlights its promising prospects for applications in optoelectronic devices, such as organic light-emitting diodes (OLEDs).