Theoretical Investigation on the Electronic Structures and Optoelectronic Properties of a Series of Platinum(II) Complexes with Different Substituent Groups

A theoretical investigation was performed on a series of platinum(II) complexes with the dipivaloylmethane as ancillary ligand and tetrahydroquinolines with different substituent group (-CF₃, -CN, -H, -CH₃, and -OCH₃) as C^N cyclometalating ligand. The geometry structures, electronic structures, absorption, and phosphorescent properties of these platinum(II) complexes have been investigated. Ionization potential and electron affinity were calculated to evaluate the injection abilities of holes and electrons into these complexes. The lowest energy absorption wavelengths are located at 362 nm for 1, 372 nm for 2, 361 nm for 3, 361 nm for 4, and 355 nm for 5, respectively. The lowest energy emissions of these complexes are localized at 520, 544, 513, 519, and 523 nm, respectively, for complexes 1-5, simulated in CH₂Cl₃ medium at M062X level. The calculated results indicate that the complex 2 possibly possesses the largest k_r value among the five complexes. It is expected that the study can be useful for designing and synthesizing the new phosphorescent OLEDs materials.