Theoretical Investigation On Platinum(â…¡) Complexes Containing Triarylboron

In this paper, we employed the density functional theory (DFT) and Time-dependent DFT (TD-DFT) to investigate the effect of triarylboron substituents based on a series of Pt(II) complexes containing donor of N-heterocyclic carbenes (NHCs)aiming at searching efficient blue-emitting phosphorescent materials. In order to reveal the relationship between the structure and photophysical properties, we conduct the analysis of some key parameters, such as the d-orbital splitting, zero-field splitting(ZFS), radiative rate constant and radiative lifetime and so on. We hope the analyses and dicussions in this work would be helpful to comprehend the structure-property relationships of Pt(Ⅱ) complexes containing triarylboron substituents in experimentally and theoretically when designing or synthesizing new phosphorescent compounds.1.Theoretical Insight Into the Role of Triarylboron in Tetradentate Dianionic bis (N-heterocyclic carbene) Platinum (Ⅱ) Chelate:Improving the Performance of Blue Light EmissionThe electronic structures and photophysical properties of eleven Pt (Ⅱ)-complexes divided into three series by the degree of% conjugation were studied using density functional theory (DFT) and time-dependent density functional theory (TDDFT). To investigate the effect of triarylboron substituents, the changes transformed by the extension of the π conjugation and even the non-radiative and radiative decay efficiency, the geometric relaxations, d-orbital splitting and spin-orbit couplings at the optimized So and Ti geometries were computed. The results show that complexes with the triarylboron substituents may have higher phosphorescent efficiencies as compared to the cyano group. Besides,3-series with larger π conjugation (anthracene groups) may weaken the effects caused by the introduction triarylboron substituents and are less likely to possess an enhanced phosphorescent efficiency, relatively. Furthermore, the absorption spectra and emission color were predicted, which indicated complexes connecting with triarylboron substituents in series 1 and 2 would emit blue colors, but the emission colors of series 3 located in the region of near-infared because of the larger π conjugation. This work highlights that the introduction of the triarylboron substituents and proper π conjugation (naphthalene groups) can help to achieve highly efficient phosphorescence in those complexes containing donor of N-heterocyclic carbenes (NHCs).2. The design and theoretical investigation on platinum (Ⅱ) complexes connecting with triarylboronDensity function theory (DFT) and Time-dependent DFT (TD-DFT) were employed to investigate the properties of three cyclometalated Pt(Ⅱ) complexes at the B3LYP/LANL2DZ. By virtue of the character of donor-acceptor triarylboron metal complexes which can show intense donor-acceptor charge transfer luminescence with high quantum efficiencies, the diphenylamine were also introduced. The non-radiative and radiative decay rate were estimated by the analysis of the geometric relaxations, d-orbital splitting, zero-field splitting(ZFS), radiative rate constant and radiative lifetime at the optimised So and T1 geometries. In addition, the reorganization energy were also computed to evaluate the charge transport quality. In a word, all the calculated results reveal that the complex only connecting triarylboron tend to become the potentially promising candidates for efficient blue-emitting phosphorescent materials, which is due to its larger radiative rate constant, shorter radiative lifetime and balanced charge transfer rate and so on. But the complex connecting with triarylboron group and diphenylamine group shows weaker performance in improving the higher photoluminescent quantum efficiency, which is because of the smaller radiative rate constant, longer radiative lifetime and so on.