Hyperfine Interactions and Electron Spin Distribution in Triplet-State Naphthalene

Hirota, Noboru; Hutchison, Clyde A.; Palmer, Patrick

doi:10.1063/1.1725081

Cited by 102 publications

(26 citation statements)

References 22 publications

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“…The spin hamiltonian parameters derived from values of the stationary resonance fields [1] are collected in table 1. They are in good agreement with values reported previously for N [1,2] and 2FN [6].…”

Section: Fine Structuresupporting

confidence: 93%

“…A similar variation is also observed upon deuterium substitution [2,17]. We think that this effect is much too small to cast serious doubt on our hypothesis.…”

Section: Fine Structuresupporting

confidence: 74%

“…According to Hirota et al [2] the spin densities in phosphorescent naphthalene are p~=0.219, p~=0.062, PT= -0"063.…”

Section: Fine Structurementioning

confidence: 98%

“…The crudeness of a simple point dipole model did not allow for confidently evaluating such small variations but it confirmed that the observed changes are within the limit of precision of the evaluated spin densities in N. Furthermore it was calculated that the asymmetrical fluorine substitution did not significantly alter the orientation of the axes of the fine structure tensor with respect to the molecular framework. These values have been used successfully in the analysis of proton h.f.s, in naphthalene [2], benzene [14] and anthracene [15]. (ii) The interaction with electronic spin densities located two or more bonds away was introduced through the approximate procedure of de Groot et al [14].…”

Section: Fine Structurementioning

confidence: 99%

“…due to hydrogen nuclei provides a quantitative measure of the spin density in the zr-electron system. As Hutchison and his co-workers [1,2] [2] used experimental and theoretical results on the malonyl radical [3,4,9]. This species was considered as the prototype of a planar, \ sp 2 hybridized C-H fragment.…”

Section: Introductionmentioning

confidence: 98%

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Electron spin resonance of phosphorescent fluorine-substituted aromatics

Mispelter¹,

Grivet²,

Lhoste

1971

Molecular Physics

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The lowest excited triplet state of the three compounds naphthalene, 1-fluoronaphthalene and 2-fluoronaphthalene, has been investigated by electron spin resonance spectroscopy. The phosphorescent molecules were oriented and diluted in durene single crystals. Zero field energies, principal values of the g tensors and hyperfine coupling constants for hydrogen and fluorine nuclei in the three canonical orientations are reported. A detailed comparative analysis of these results shows that the presence of fluorine has little effect on the ,r-electron distribution in the excited state. Upon substitution, some of the spin density originally present in the carbon 2p~ orbital spreads onto the fluorine atom. Spin densities on other carbon atoms remain constant. This local perturbation model is used to analyse in detail the magnetic properties of phosphorescent 1-and 2-fluoronaphthalene. From the spin densities and the experimental coupling constants, the hyperfine tensor of a C-F fragment bearing unit spin density is derived. This tensor is then broken down into four contributions which are computed using a minimum number of assumptions. The results are: (i) accurate experimental data pertaining to the nature of the C-F bond and its spin delocalization and polarization mechanisms; (ii) a firmly-established hyperfine tensor for fluorine \, in a planar, sp ~ hybridized C-F fragment. A simple method to determine // spirt densities using fluorine hyperfine structure as a probe is outlined.

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Section: Fine Structuresupporting

confidence: 93%

“…A similar variation is also observed upon deuterium substitution [2,17]. We think that this effect is much too small to cast serious doubt on our hypothesis.…”

Section: Fine Structuresupporting

confidence: 74%

“…According to Hirota et al [2] the spin densities in phosphorescent naphthalene are p~=0.219, p~=0.062, PT= -0"063.…”

Section: Fine Structurementioning

confidence: 98%

Section: Fine Structurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

See 3 more Smart Citations

Electron spin resonance of phosphorescent fluorine-substituted aromatics

Mispelter¹,

Grivet²,

Lhoste

1971

Molecular Physics

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A Kinetically Stabilized Nitrogen‐Doped Triangulene Cation: Stable and NIR Fluorescent Diradical Cation with Triplet Ground State

Arikawa

Shimizu

Shiomi³

et al. 2023

Angewandte Chemie

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A kinetically‐stabilized nitrogen‐doped triangulene cation derivative has been synthesized and isolated as the stable diradical with a triplet ground state that exhibits near‐infrared emission. As was the case for a triangulene derivative we previously synthesized, the triplet ground state with a large singlet‐triplet energy gap was experimentally confirmed by magnetic measurements. In contrast to the triangulene derivative, the nitrogen‐doped triangulene cation derivative is highly stable even in solution under air and exhibits near‐infrared absorption and emission because the alternancy symmetry of triangulene is broken by the nitrogen cation. Breaking the alternancy symmetry of triplet alternant hydrocarbon diradicals by a nitrogen cation would therefore be an effective strategy to create stable diradicals possessing magnetic properties similar to the parent hydrocarbons but with different electrochemical and photophysical properties.

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A Kinetically Stabilized Nitrogen‐Doped Triangulene Cation: Stable and NIR Fluorescent Diradical Cation with Triplet Ground State

Arikawa

Shimizu

Shiomi³

et al. 2023

Angew Chem Int Ed

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A kinetically-stabilized nitrogen-doped triangulene cation derivative has been synthesized and isolated as the stable diradical with a triplet ground state that exhibits near-infrared emission. As was the case for a triangulene derivative we previously synthesized, the triplet ground state with a large singlet-triplet energy gap was experimentally confirmed by magnetic measurements. In contrast to the triangulene derivative, the nitrogen-doped triangulene cation derivative is highly stable even in solution under air and exhibits nearinfrared absorption and emission because the alternancy symmetry of triangulene is broken by the nitrogen cation. Breaking the alternancy symmetry of triplet alternant hydrocarbon diradicals by a nitrogen cation would therefore be an effective strategy to create stable diradicals possessing magnetic properties similar to the parent hydrocarbons but with different electrochemical and photophysical properties.

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Hyperfine Interactions and Electron Spin Distribution in Triplet-State Naphthalene

Cited by 102 publications

References 22 publications

Electron spin resonance of phosphorescent fluorine-substituted aromatics

Electron spin resonance of phosphorescent fluorine-substituted aromatics

A Kinetically Stabilized Nitrogen‐Doped Triangulene Cation: Stable and NIR Fluorescent Diradical Cation with Triplet Ground State

A Kinetically Stabilized Nitrogen‐Doped Triangulene Cation: Stable and NIR Fluorescent Diradical Cation with Triplet Ground State

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