TY - JOUR
T1 - Delayed fluorescence from a zirconium(iv) photosensitizer with ligand-to-metal charge-transfer excited states
AU - Zhang, Yu
AU - Lee, Tia S.
AU - Favale, Joseph M.
AU - Leary, Dylan C.
AU - Petersen, Jeffrey L.
AU - Scholes, Gregory D.
AU - Castellano, Felix N.
AU - Milsmann, Carsten
N1 - Publisher Copyright:
© 2020, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2020/4/1
Y1 - 2020/4/1
N2 - 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)2 engages 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. [Figure not available: see fulltext.]
AB - 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)2 engages 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. [Figure not available: see fulltext.]
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U2 - 10.1038/s41557-020-0430-7
DO - 10.1038/s41557-020-0430-7
M3 - Article
C2 - 32203439
AN - SCOPUS:85081932352
SN - 1755-4330
VL - 12
SP - 345
EP - 352
JO - Nature chemistry
JF - Nature chemistry
IS - 4
ER -