Yan Xianju, Xue Jianan, Wang Yue
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.
Jihua Hengye Electronic Materials CO. LTD. Foshan, Guangdong Province 528200, P. R. China.
Inorg Chem. 2023 Jan 30;62(4):1476-1487. doi: 10.1021/acs.inorgchem.2c03602. Epub 2023 Jan 19.
In order to construct a new type of ruthenium(II) terpyridine complexes with activated triplet metal-centered (MC) states, as well as stabilized triplet metal-to-ligand charge transfer (MLCT) states, conducive to fine emissive performances, , , , and were synthesized. Compared with the [Ru(terpyridine)] prototype (0.25 ns), this series of ruthenium(II) terpyridine complexes exhibit lengthened excited state lifetime (43.3 ns for , 52.7 ns for , 43.6 ns for , and 53.4 ns for ). Interfragment charge transfer analysis illustrates the electron transfer direction of the four complexes, manifesting their intramolecular charge transfer characteristic. When excited, their lowest-lying triplet states are assigned as MLCT based on spin-density surface distribution. The singlet excited states and MLCT states were thoroughly studied by UV-visual absorption and nanosecond time-resolved transient absorption spectra, respectively. Photoluminescence spectra revealed their weak broadband near-infrared emission at room temperature and red phosphorescence at 77 K. The low molecular weight and the good thermal stability make and suitable for vaporization coating, while the fine solubility in common organic solvents makes and suitable for solution processing. Furthermore, the intrinsic electroneutrality and favorable energy levels endow them with new potential to be applied in the optoelectronic field.
