Pižl, Martin and Hunter, Bryan M. and Sazanovich, Igor V. and Towrie, Michael and Gray, Harry B. and Záliš, Stanislav and Vlček, Antonín (2022) Excitation-Wavelength-Dependent Photophysics of d⁸d⁸ Di-isocyanide Complexes. Inorganic Chemistry, 61 (6). pp. 2745-2759. ISSN 0020-1669. doi:10.1021/acs.inorgchem.1c02645. https://resolver.caltech.edu/CaltechAUTHORS:20211220-955752000
Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20211220-955752000
Abstract
Binuclear Rh(I) and Ir(I) TMB (2,5-dimethyl-2,5-diisocyanohexane) and dimen (1,8-diisocyanomenthane) complexes possess dσ*pσ and dπpσ singlet and triplet excited states that can be selectively excited in the visible and UV spectral regions. Using perturbational spin–orbit TDDFT, we unraveled the detailed character and spin mixing of these electronic transitions and found that delocalization of pσ and dπ orbitals over C≡N– groups makes C≡N stretching vibrations sensitive reporters of electron density and structural changes upon electronic excitation. Picosecond time-resolved infrared spectra measured after visible light, 375 nm, and 316 nm excitation revealed excitation-wavelength-dependent deactivation cascades. Visible light irradiation prepares the ¹dσ*pσ state that, after one or two (sub)picosecond relaxation steps, undergoes 70–1300 ps intersystem crossing to ³dσ*pσ, which is faster for the more flexible dimen complexes. UV-excited ^(1,3)dπpσ states decay with (sub)picosecond kinetics through a manifold of high-lying triplet and mixed-spin states to ³dσ*pσ with lifetimes in the range of 6–19 ps (316 nm) and 19–43 ps (375 nm, Ir only), bypassing ¹dσ*pσ. Most excited-state conversion and some relaxation steps are accompanied by direct decay to the ground state that is especially pronounced for the most flexible long/eclipsed Rh(dimen) conformer.
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Alternate Title: | Excitation-Wavelength-Dependent Photophysics of d8d8 Di-isocyanide Complexes | ||||||||||||||||
Additional Information: | © 2021 American Chemical Society. Received: August 26, 2021; Published: December 14, 2021. This research was supported by the Czech Science Foundation (GAČR) grant no. 21-05180S, the Czech Ministry of Education (MŠMT) grant no. LTAUSA18026, EPSRC (UK) grant no. EP/R029687/1, the STFC Rutherford Appleton Laboratory (UK), the United States National Science Foundation (CHE-1763429), and the Arnold and Mabel Beckman Foundation. The authors declare no competing financial interest. | ||||||||||||||||
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Subject Keywords: | Oscillation, Molecular structure, Quantum mechanics, Transition metals, Kinetics | ||||||||||||||||
Issue or Number: | 6 | ||||||||||||||||
DOI: | 10.1021/acs.inorgchem.1c02645 | ||||||||||||||||
Record Number: | CaltechAUTHORS:20211220-955752000 | ||||||||||||||||
Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20211220-955752000 | ||||||||||||||||
Official Citation: | Excitation-Wavelength-Dependent Photophysics of d8d8 Di-isocyanide Complexes. Martin Pižl, Bryan M. Hunter, Igor V. Sazanovich, Michael Towrie, Harry B. Gray, Stanislav Záliš, and Antonín Vlček. Inorganic Chemistry 2022 61 (6), 2745-2759; DOI: 10.1021/acs.inorgchem.1c02645 | ||||||||||||||||
Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | ||||||||||||||||
ID Code: | 112590 | ||||||||||||||||
Collection: | CaltechAUTHORS | ||||||||||||||||
Deposited By: | George Porter | ||||||||||||||||
Deposited On: | 21 Dec 2021 15:45 | ||||||||||||||||
Last Modified: | 02 Mar 2022 18:14 |
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