Combined Machine Learning, Computational, and Experimental Analysis of the Iridium(III) Complexes with Red to Near-Infrared Emission

• Published in: The journal of physical chemistry letters Vol. 15; no. 2; pp. 471 - 480
• Main Authors: Karuth, Anas, Casanola-Martin, Gerardo M., Lystrom, Levi, Sun, Wenfang, Kilin, Dmitri, Kilina, Svetlana, Rasulev, Bakhtiyor
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 18.01.2024
• Subjects: Chemistry; Materials Science; Physical Insights into Materials and Molecular Properties; Physics; Science & Technology - Other Topics
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.3c02533

Various coordination complexes have been the subject of experimental and theoretical studies in recent decades because of their fascinating photophysical properties. In this work, a combined experimental and computational approach was applied to investigate the optical properties of monocationic Ir­(III) complexes. An interpretative machine learning-based quantitative structure–property relationship (ML/QSPR) model was successfully developed that could reliably predict the emission wavelength of the Ir­(III) complexes and provide a foundation for the theoretical evaluation of the optical properties of Ir­(III) complexes. A hypothesis was proposed to explain the differences in the emission wavelengths between structurally different individual Ir­(III) complexes. The efficacy of the developed model was demonstrated by high R 2 values of 0.84 and 0.87 for the training and test sets, respectively. It is worth noting that a relationship between the N–N distance in the diimine ligands of the Ir­(III) complexes and emission wavelengths is detected. This effect is most probably associated with a degree of distortion in the octahedral geometry of the complexes, resulting in a perturbed ligand field. This combined experimental and computational approach shows great potential for the rational design of new Ir­(III) complexes with the desired optical properties. Moreover, the developed methodology could be extended to other transition-metal complexes.