Graduate School of Chemical Sciences and Technology, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.
Photochem Photobiol Sci. 2018 Jul 11;17(7):883-888. doi: 10.1039/c8pp00210j.
A macroring composed of three Cu(ii) porphyrins (CuP) and three slipped-cofacial Zn(ii) porphyrin (ZnP2) dimers exhibited near-IR emission from the CuP part. The emission lifetime of the macroring (15 μs) was 500 times longer compared to that of a Cu porphyrin monomer (e.g., Cu(ii)TPP; TPP = meso-tetraphenylporphyrin). The observed emission is ascribed to emission via the reservoir mechanism from the trip-doublet (2T1) state in CuP thermally activated from the T1 state of ZnP2, which is located ca. 1030 cm-1 below the 2T1 state of CuP. The near-IR emission of the macroring was significantly quenched by O2, whereas that of the Cu porphyrin monomer was hardly quenched, indicating that the quenching event mainly occurred on the T1 state of the ZnP2 parts. The nonemissive triplet state of a Zn porphyrin at room temperature was visualized through emission from a neighboring Cu porphyrin.
一个由三个 Cu(ii)卟啉（CuP）和三个 slipped-cofacial Zn(ii)卟啉（ZnP2）二聚体组成的大环表现出来自 CuP 部分的近红外发射。大环的发射寿命（15 μs）比 Cu 卟啉单体（例如 Cu(ii)TPP；TPP = 间四苯基卟啉）长 500 倍。观察到的发射归因于通过储库机制从热激活自 ZnP2 的 T1 态的三重态-二倍态（2T1）状态发射，该状态位于 CuP 的 2T1 态下方约 1030 cm-1。大环的近红外发射被 O2 显著猝灭，而 Cu 卟啉单体的发射几乎未被猝灭，表明猝灭事件主要发生在 ZnP2 部分的 T1 态上。室温下 Zn 卟啉的非发光三重态通过邻近的 Cu 卟啉的发射可视化。
