Wang Li, Wu Yong, Geng Yun, Wu Jie, Zhu Dong-Xia, Su Zhong-Min
Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University , Changchun 130024, China.
J Phys Chem A. 2014 Jul 10;118(27):5058-67. doi: 10.1021/jp4099649. Epub 2014 Jun 27.
The phosphorescent efficiencies of the Ir(III) carbene complexes 1-3 with wide-range color tuning were focused on in this work. A DFT/TDDFT (density functional theory/time-dependent density functional theory) investigation on the geometries in the ground and lowest triplet excited states, the frontier molecular orbitals, the absorption spectra, and d-orbital splittings of 1-3 were provided to get a better understanding of structure–property relationships. Importantly, to shed light on the difference in phosphorescent quantum yields for 1-3, radiative decay constants as well as zero-field-splitting parameters were calculated based on the estimation of spin–orbit coupling (SOC) matrix elements denoted as T(α1)|H(SOC)|S(n). The results show that, for any complex, the radiative decay rates in the three substates (namely, T(x), T(y), and T(z0) are not equal, and the largest radiative rates of 1-3 are all located in x substates with values of 1.0764 × 10(4), 0.8231 × 10(4), and 1.9596 × 10(4) s(–1), respectively. Moreover, for 3 with the highest quantum efficiency, we make efforts to modify it through varying substituents and substituent positions not only to achieve blue shift in the emission but also to obtain improved triplet energy.
本工作聚焦于具有宽范围颜色调谐的铱（III）卡宾配合物1-3的磷光效率。通过密度泛函理论/含时密度泛函理论（DFT/TDDFT）对1-3在基态和最低三重激发态的几何结构、前沿分子轨道、吸收光谱以及d轨道分裂进行了研究，以更好地理解结构-性质关系。重要的是，为了阐明1-3磷光量子产率的差异，基于对自旋-轨道耦合（SOC）矩阵元T(α1)|H(SOC)|S(n)的估计，计算了辐射衰变常数以及零场分裂参数。结果表明，对于任何配合物，三个亚态（即T(x)、T(y)和T(z0)）的辐射衰变率不相等，1-3的最大辐射率均位于x亚态，其值分别为1.0764×10(4)、0.8231×10(4)和1.9596×10(4) s(–1)。此外，对于量子效率最高的3，我们努力通过改变取代基和取代基位置对其进行修饰，不仅实现发射的蓝移，还获得提高的三重态能量。
