Delayed fluorescence from a zirconium(iv) photosensitizer with ligand-to-metal charge-transfer excited states
Delayed fluorescence from a zirconium(iv) photosensitizer with ligand-to-metal charge-transfer excited states
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DOI：
10.1038/s41557-020-0430-7
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发表时间：
2020-03
期刊：
影响因子：
21.8
通讯作者：
Yu Zhang;Tia S. Lee;Joseph M. Favale;Dylan C. Leary;J. L. Petersen;G. Scholes;F. Castellano;Carsten Milsmann
中科院分区：
文献类型：
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作者：
Yu Zhang;Tia S. Lee;Joseph M. Favale;Dylan C. Leary;J. L. Petersen;G. Scholes;F. Castellano;Carsten Milsmann
过渡金属配合物的光物理性质在化学控制方面取得的进展正在改变一系列技术，特别是光催化和发光二极管，但它们严重依赖于含有贵金属的分子，如钌和铱。虽然地球上丰富的“早期”过渡金属在光敏剂中的应用显然是有利的，但对具有配体到金属电荷转移（LMCT）特征的激发态的详细了解对于解释其不同的电子构型至关重要。在这里，我们报道了一种空气和水分稳定，可见光吸收的Zr（iv）光敏剂Zr(MesPDPPh)2，其中[MesPDPPh]2−是[2,6-二（5-（2,4,6-三甲基苯基）-3-苯基- 1h -吡啶-2-基）吡啶]的双去质子化形式。该分子具有超长寿命的三重态LMCT激发态（τ= 350 μs），由于热激活的延迟荧光从具有显著LMCT贡献的高单线态发出，具有高效的光致发光发射（Ф= 0.45）。Zr(MesPDPPh)2参与多种光氧化还原催化过程和三重态能量转移。我们的研究为未来光敏剂的发展提供了蓝图，这些光敏剂具有早期过渡金属和具有重要LMCT贡献的激发态。
Advances in chemical control of the photophysical properties of transition-metal complexes are revolutionizing a wide range of technologies, particularly photocatalysis and light-emitting diodes, but they rely heavily on molecules containing precious metals such as ruthenium and iridium. Although the application of earth-abundant ‘early’ transition metals in photosensitizers is clearly advantageous, a detailed understanding of excited states with ligand-to-metal charge transfer (LMCT) character is paramount to account for their distinct electron configurations. Here we report an air- and moisture-stable, visible light-absorbing Zr(iv) photosensitizer, Zr(MesPDPPh)2, where [MesPDPPh]2−is the doubly deprotonated form of [2,6-bis(5-(2,4,6-trimethylphenyl)-3-phenyl-1H-pyrrol-2-yl)pyridine]. This molecule has an exceptionally long-lived triplet LMCT excited state (τ= 350 μs), featuring highly efficient photoluminescence emission (Ф= 0.45) due to thermally activated delayed fluorescence emanating from the higher-lying singlet configuration with significant LMCT contributions. Zr(MesPDPPh)2engages in numerous photoredox catalytic processes and triplet energy transfer. Our investigation provides a blueprint for future photosensitizer development featuring early transition metals and excited states with significant LMCT contributions.