DOI: https://doi.org/10.55373/mjchem.v28i5.57

Keywords: Iridium(III) complex, cyclometalated, luminescent, alkoxy-functionalised, 2-phenylpyridine

Abstract

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-(2-butoxy-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 1.00–4.09 ppm, corresponding to the ethyl and butyl chain protons, while signals in the δ 5.99–8.81 ppm 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 λ_em = 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).