Spectroscopy and formation of lanthanum-hydrocarbon radicals formed by association and carbon-carbon bond cleavage of isoprene

Cao, Wenjin; Hewage, Dilrukshi; Yang, Dong‐Sheng

doi:10.1063/1.5026899

Cited by 3 publications

(2 citation statements)

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“…Gas-phase titanium oxide clusters can be used as ideal models of the active sites on titania materials. − The structures and reactivity of small to nanosized titanium oxide clusters have been extensively studied. − The study of the interactions of titanium oxide clusters with CO under dark conditions demonstrated the outstanding reactivity of the titanium oxide clusters with specific compositions ((TiO 2 ) x O – and (TiO 2 ) x + ) that have atomic oxygen radical anions (O •– ) as the active sites. , It has been proposed that (TiO 2 ) x O – clusters with x values of up to 50 still have the O •– radicals . Although there have been many studies on the reactivity of titanium oxide clusters under dark conditions, the photoactivity of these oxide clusters has been almost untouched …”

Section: Introductionmentioning

confidence: 99%

Photooxidation of Isoprene by Titanium Oxide Cluster Anions with Dimensions up to a Nanosize

Liu

Zhao

et al. 2021

J. Am. Chem. Soc.

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Titania (TiO 2 ) nanoparticles are active photocatalysts, and isoprene (C 5 H 8 ) is a biogenic volatile organic compound that contributes crucially to global particulate matter generation. Herein, the direct photooxidation of isoprene by titanium oxide cluster anions with dimensions up to a nanosize by both ultraviolet (UV) and visible (Vis) light excitations has been successfully identified through mass spectrometric experiments combined with quantum chemistry calculations. The potential role of "dry" titania in atmospheric isoprene oxidation has been revealed, and a clear picture of the photooxidation mechanism on titanium oxide nanoparticles has been provided explicitly at the molecular level. The adsorption of isoprene on the atomic oxygen radicals (O •− ) of titanium oxide clusters leads to the formation of the crucial interfacial state (IS) within the band gap of titanium oxides. This IS is demonstrated to be the significant factor in delivering the electron from the π orbital of C 5 H 8 to the Ti 3d orbital in the photooxidation process (C 5 H 8 + Ti 4+ −O •− → C 5 H 8 O + Ti 3+ ) and creating photoactivity in the Vis region. It is revealed that after the photogeneration of the O •− radicals by UV excitation on the TiO 2 particle surface, the subsequent reactions can be induced by Vis excitation through the IS. This multicolor strategy in both the UV and Vis regions can enhance the efficiency of solar energy harvesting and improve the product yield of the photocatalysis on TiO 2 nanoparticles. New insights have been provided into both the atmospheric chemistry of isoprene and the photochemistry of TiO 2 nanoparticles.

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Section: Introductionmentioning

confidence: 99%

Photooxidation of Isoprene by Titanium Oxide Cluster Anions with Dimensions up to a Nanosize

Liu

Zhao

et al. 2021

J. Am. Chem. Soc.

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“…Gas phase studies on atomic clusters provide an ideal arena for probing chemical activities and mechanisms in an unperturbed environment. − Iron oxide clusters, with unique magnetic, biochemical and catalytic properties, have attracted broad interest in gas phase studies with mass spectrometry, − spectroscopy, − and quantum chemistry calculations. − The reactions of positively charged iron oxide clusters with isoprene have been studied, and the size-dependent reactivity has been identified . The net charge can affect the cluster reactivity significantly. − Neutral clusters are good models for the active sites of bulk metal oxides without charge effects .…”

Section: Introductionmentioning

confidence: 99%

Oxidation of Isoprene by Neutral Iron Oxide Nanoclusters in the Gas Phase

Liu

Chen

et al. 2019

J. Phys. Chem. C

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Understanding the heterogeneous oxidation of isoprene is crucial to discover the missing sink of the atmospheric isoprene. Iron oxide nanoparticles dominate the most abundant type of anthropogenic Fe-bearing particles in the atmosphere. In this study, by using a homemade time-of-flight mass spectrometer coupled with a laser ablation cluster source and a vacuum ultraviolet laser system, the neutral iron oxide clusters (Fe x O y ) with the size up to 1 nm have been successfully generated and detected. The reactions of Fe x O y with isoprene (C5H8) to form CH2O, C4H6O, and C5H6O have been identified, and the mechanisms of Fe4O6 + C5H8 have been interpreted by using the quantum chemistry calculations. Based on the experimentally observed size-dependent reactivity, the total contribution of atmospheric iron oxide nanoparticles to isoprene heterogeneous oxidation has been estimated to be comparable with the contribution of OH radicals that are the dominant species for isoprene oxidation in the current atmospheric chemistry models. The heterogeneous oxidation of isoprene by iron oxide clusters is thus very important in atmospheric chemistry.

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Lanthanum‐ and Cerium‐Mediated CH Activation: Spectroscopy, Structures, and Formation of Metal‐Containing Intermediates

Cao¹,

Yang²

2022

Handbook of CH-Functionalization

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This article examines vibronic spectra, isomeric structures, and formation of transient metal complexes produced in La‐ and Ce‐mediated CH activation reactions of hydrocarbon compounds in the gas phase. The hydrocarbon compounds include small alkenes, alkynes, and alkadienes. Molecular masses of metal complexes are measured with time‐of‐flight mass spectrometry, vibronic spectra are probed with mass‐analyzed threshold ionization (MATI) spectroscopy, and isomeric structures are determined by comparing experimental and computational vibronic spectra, and plausible reaction pathways for the formation of specific isomers are investigated by quantum chemical calculations.

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Spectroscopy and formation of lanthanum-hydrocarbon radicals formed by association and carbon-carbon bond cleavage of isoprene

Cited by 3 publications

References 64 publications

Photooxidation of Isoprene by Titanium Oxide Cluster Anions with Dimensions up to a Nanosize

Photooxidation of Isoprene by Titanium Oxide Cluster Anions with Dimensions up to a Nanosize

Oxidation of Isoprene by Neutral Iron Oxide Nanoclusters in the Gas Phase

Lanthanum‐ and Cerium‐Mediated CH Activation: Spectroscopy, Structures, and Formation of Metal‐Containing Intermediates

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