Photochemical reaction mechanisms and kinetics with molecular nanocrystals: surface quenching of triplet benzophenone nanocrystals

Simoncelli, Sabrina; Kuzmanich, Gregory; Gard, Matthew N.

doi:10.1002/poc.1659

Cited by 21 publications

(26 citation statements)

References 43 publications

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“…Fortunately, the white emission of ClBDBT is obtained at crystalline state. The dense packing of molecule within the crystal lattice will not only block the quenching of oxygen and moisture, but also prevent the degradation of molecules from inner part under ambient conditions 60 . To test the stability, crystalline powder of ClBDBT was exposed to UV irradiation for 12 h under air at room temperature.…”

Section: Resultsmentioning

confidence: 99%

White light emission from a single organic molecule with dual phosphorescence at room temperature

Zhao

Lam³

et al. 2017

Nat Commun

712

409

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The development of single molecule white light emitters is extremely challenging for pure phosphorescent metal-free system at room temperature. Here we report a single pure organic phosphor, namely 4-chlorobenzoyldibenzothiophene, emitting white room temperature phosphorescence with Commission Internationale de l’Éclair-age coordinates of (0.33, 0.35). Experimental and theoretical investigations reveal that the white light emission is emerged from dual phosphorescence, which emit from the first and second excited triplet states. We also demonstrate the validity of the strategy to achieve metal-free pure phosphorescent single molecule white light emitters by intrasystem mixing dual room temperature phosphorescence arising from the low- and high-lying triplet states.

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Section: Resultsmentioning

confidence: 99%

White light emission from a single organic molecule with dual phosphorescence at room temperature

Zhao

Lam³

et al. 2017

Nat Commun

712

409

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“…Thus, while visible transient absorption spectroscopy has revealed photophysical and photochemical mechanisms, these data do not uncover details regarding the structural changes that occur following excitation. An enduring and promising area of study for the future is the collection of time-resolved structural or atom-specific spectroscopic data that is subsequently correlated with electronic spectroscopic data, preferably in the same medium. − It is expected that kinetic analysis and results will not be identical, as atoms move much more slowly than electrons. Indeed, it is well known that femtosecond TR-IR kinetic data do not always align with visible pump–probe data on this same time scale. , While there may be many approaches to this goal, there appear to be three strategies that may well generate the most interesting results: TR-XAS, time-resolved photocrystallography, and TR-IR spectroscopy.…”

Section: Correlating Electronic Structural Changes With Atomic Struct...mentioning

confidence: 99%

A Future Perspective on Phototriggered Isomerizations of Transition Metal Sulfoxides and Related Complexes

et al. 2021

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Photochromic molecules are examples of light-activated bistable molecules. We highlight the design criteria for a class of ruthenium and osmium sulfoxide complexes that undergo phototriggered isomerization of the bound sulfoxide. The mode of action in these complexes is an excited-state isomerization of the sulfoxide from S-bonded to O-bonded. We discuss the basic mechanism for this transformation and highlight specific examples that demonstrate the effectiveness and efficiency of the isomerization. We subsequently discuss future research directions within the field of phototriggered sulfoxide isomerizations on transition metal polypyridine complexes. These efforts involve new synthetic directions, including the choice of metal as well as new ambidentate ligands for isomerization.

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“…The data were converted to a text file in the L900 software and then plotted and analyzed in the IgorPro software. Solid-state nanocrystalline suspensions were prepared following the procedure reported previously . Saturated acetone solutions of 1Br were added to a water solution in a volumetric flask placed in an ultrasound bath until the absorption at 266 nm was between 0.3 and 0.8.…”

Section: Experimental and Computational Detailsmentioning

confidence: 99%

“…Solid-state nanocrystalline suspensions were prepared following the procedure reported previously. 37 Saturated acetone solutions of 1Br were added to a water solution in a volumetric flask placed in an ultrasound bath until the absorption at 266 nm was between 0.3 and 0.8. The resulting nanocrystalline suspension was placed inside a quartz cuvette with a 10 mm × 10 mm cross section and analyzed.…”

Section: Experimental and Computational Detailsmentioning

confidence: 99%

Effects of Self-Assembly on the Photogeneration of Radical Cations in Halogenated Triphenylamines

et al. 2021

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We investigate the effect of assembly on charge transfer, charge recombination, and the persistence of radical cations in halogen-substituted triphenylamine (TPA) dimers. A series of urea-tethered TPA derivatives 1 (X = H, Cl, Br, and I) are compared, which have one phenyl group modified at the para position with a halogen. Ureas direct the assembly of these derivatives while halogen substituents influence the packing of the TPA units. These modifications affect the generation and persistence of TPA radical cations as monitored by electron paramagnetic resonance (EPR) spectroscopy. The formation and degradation pathways of the radical cations in solution and gas phase were probed by ion-mobility spectrometry mass spectrometry. In contrast, supramolecular assembly enhanced the stability of these materials as well as the persistence of their photogenerated radical cations, which appear to undergo charge recombination without degradation. Greater quantities of these radical cations are observed for the bromo and non-halogenated derivatives (1Br, 1H). Time-dependent density functional theory (TD-DFT) calculations on single molecules and hydrogen-bonded dimers suggest the stability of TPA radical cations largely depends on initial photoinduced charge separation and electronic coupling between assembled TPA dimers. The latter was found to be about 7 times stronger in 1I than in 1Br dimers, which may explain faster charge recombination and shorter lifetimes of 1I radicals. Transient absorption (TA) spectroscopy and TD-DFT were able to identify the charged species for 1Br along with the kinetic traces and measured lifetime of ∼80 ns. Fluorescence quenching studies are consistent with initial charge separation and subsequent charge transfer event between nearby TPAs. Future exploration will focus on the mobility and application of these TPA assemblies as hole transport materials.

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Photochemical reaction mechanisms and kinetics with molecular nanocrystals: surface quenching of triplet benzophenone nanocrystals

Cited by 21 publications

References 43 publications

White light emission from a single organic molecule with dual phosphorescence at room temperature

White light emission from a single organic molecule with dual phosphorescence at room temperature

A Future Perspective on Phototriggered Isomerizations of Transition Metal Sulfoxides and Related Complexes

Effects of Self-Assembly on the Photogeneration of Radical Cations in Halogenated Triphenylamines

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