Acta Chim. Sinica ›› 2016, Vol. 74 ›› Issue (9): 764-772.DOI: 10.6023/A16060308 Previous Articles    



马明硕a,b, 邹陆一a, 李岩c, 任爱民a, 丁晓丽a   

  1. a 吉林大学理论化学研究所 长春 132023;
    b 吉林化工学院分析测试中心 吉林 132022;
    c 吉林化工学院化学与制药工程学院 吉林 132022
  • 投稿日期:2016-06-24 发布日期:2016-08-10
  • 通讯作者: 任爱民
  • 基金资助:


Theoretical Studies on Photophysical Properties of Isomeric Iridium(Ⅲ) Complexes Ir(ppy)2(acac) Containing Dimesitylboron Moiety

Ma Mingshuoa,b, Zou Luyia, Li Yanc, Ren Aimina, Ding Xiaolia   

  1. a Institute of Theoretical Chemistry, Jilin University, Changchun 132023;
    b Center of Analysis and Measurement, Jilin Institute of Chemical Technology, Jilin City 132022;
    c School of Chemical and Pharmaceutical Engineering, Jilin Institute of Chemical Technology, Jilin City 132022
  • Received:2016-06-24 Published:2016-08-10
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21473071, 21173099 and 20973078), the National Basic Research Program of China (973 Program) (No. 2013CB834801) and the Youth Program of National Natural Science Foundation of China (No. 11504130).

The phosphorescent photophysical properties for three Ir(Ⅲ) complexes 13 containing dimesitylboryl moiety were investigated by DFT. The electronic structure of the ground and excited state, absorption and emission spectra, the spin-orbital coupling matrix < T1α|HSOC|Sn >, the radiative and non-radiative transition process for complexes 13 were calculated by DFT/TD-DFT approach. The effect of dimesitylboryl substitution at different site of Ir(Ⅲ) complex with phenylpyridine and acetylacetone ligand on the phosphorescent radiative and non-radiative process was discussed. The results reveal that the introduction of B(Mes)2 group to the pyridine ring of the phenylpyridine (ppy) ligand can strengthen the interactions between the metal and the acetylacetone (acac) ligand, reduce the structure relaxation of the molecule from the ground state to the excited triplet state, and maintain the structures of octahedral field, which is conducive to restricted non-radiative transition. Moreover the singlet-triplet energy splitting ΔE(S1-T1) is decreased, the intersystem crossing rate and radiative transition rate are increased. In addition, compared with the substitution at the pyridinyl in complex 1, modifying phenyl group with B(Mes)2 group in complex 2 and 3 could induce larger structural changes from S0 to T1 state and enhance the < S0|HSOC|T1 > value, the spin orbit coupling matrix element between S0 and T1 state of 2 and 3 are greater than that of 1, which will induce a larger non-radiative transition rate for 2 and 3. The variety of substitution position of B(Mes)2 group leads to different d-splitting, different spin-orbital coupling effect in the x, y or z direction, induces the changes of zero field splitting energy and the inequality of radiative transition rates in the three substates (namely, krx, kry, and krz), and the largest radiative rates of 13 are all located in z substates with values of 2.32×105, 1.20×105, and 5.50×105 s-1, respectively. Therefore, we explained the reason that complex 1 has higher phosphorescence quantum efficiency through modifying the pyridine ring of the ppy ligand rather than the benzene ring.

Key words: B(Mes)2, spin-orbit coupling, radiative transition rate, phosphorescence quantum efficiency