Probing the Effects of the Number and Positions of −OCH3 and −CN Substituents on Color Tuning of Ir(III) Complex Derivatives through a Joint Computational and Experimental Study

Abstract We performed a joint theoretical and experimental study on sixteen Ir(III) complexes bearing a similar molecular platform of bis(2‐phenylbenzothiozolato‐ N,C 2’ ) iridium(III) (acetylacetonate) by grafting −OCH 3 group and/or −CN group on different positions of the C‐related arene moiety of the ligand (C‐ring). Our results reveal that the introduction of −CN renders an overall drop in the FMO energy levels while a reverse increase is observed for −OCH 3 . The ortho ‐ and para‐sites of the C‐ring are more effective substitution positions to modulate the HOMO energy level due to the fact that the electronic density of HOMO mainly locates at them while the meta‐site would induce a stronger impact on LUMO since the electronic density of LUMO mainly distributes over the position. Utilizing the synergistic effects of the substituents and the substituted positions, a wide color‐tuning range from 479 nm to 637 nm was achieved, which covers nearly the whole window of visible spectrum. In particular, the tri‐substituted Ir35mo4cn complex (λ em max =637 nm) may be a potential candidate for high efficiency red OLEDs materials due to its greatly enhanced absorption processes, relatively higher 3 MLCT (%), lower ΔE S1–T1 , enlarged separation between 3 MLCT/π–π* and 3 MC d–d states, and good hole and particle‐transporting performances. Finally, six representative complexes were synthesized and their spectra were determined, which confirm the reliability of our computational strategy.