Ionization energies of selenophen, tellurophen and some of their derivatives

Distefano, G.; Pignataro, S.; Innorta, G.; Fringuelli, Francesco; Marino, Gianlorenzo; Taticchi, A.

doi:10.1016/0009-2614(73)80551-2

Cited by 41 publications

(10 citation statements)

References 5 publications

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“…22 The other is obtained by the electron impact technique, and as noted by the author: "electron impact values are 0.1-0.2 eV higher than the more accurate photon impact values". 23 Hence, taking account of these corrections means that all calculated DIP values should lie within experimental limits. Removing these outliers from the data set gives a MAD of 0.099 eV (2.28 kcal mol −1 ) for data spanning a range of 1.8 eV.…”

Section: Evaluation Of the Models For Ip And Bde Determinationmentioning

confidence: 98%

“…32, 33 The benzoselenete 8c was calculated to be 13.96 kcal mol −1 more stable than its valence isomer 9c at B3LYP/6-31++G(2d,p) level (Scheme 3). 23 Benzotelluretes have to the best of our knowledge never been synthesized. In order to assess the stabilities of the full series of compounds 4a-d, the relative energies of the closed (8) and open (9) valence isomers were calculated (Scheme 3, Table 3).…”

Section: Stability Of the 4-membered Ring Analoguesmentioning

confidence: 99%

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Design principles for α-tocopherol analogues

et al. 2006

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An (RO)B3LYP/LANL2DZdp//B3LYP/LANL2DZ model for the prediction of the homolytic bond dissociation enthalpy (BDE) and adiabatic ionisation potential (IP) of phenolic antioxidants containing heavy chalcogens has been developed. The model has been used to probe the relationship between geometry, chalcogen substitution and activity for a series of alpha-tocopherol analogues of varying ring size. From this, a series of design principles for cyclic antioxidants has emerged, embodied by the compound 4-hydroxy-2,2,3,5,6-pentamethylbenzoselenete (4c). This compound is predicted to have a BDE comparable to alpha-tocopherol, and should act in a dual chain-breaking and hydroperoxide-decomposing manner, by analogy with other selenide antioxidants. The stability of chalcogen-substituted benzoxetes was considered, and the as yet unsynthesised benzotelluretes are predicted to be stable. Finally, an attempt was made to determine antioxidant mechanism by considering calculated BDE and IP data together with experimental rate data.

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Section: Evaluation Of the Models For Ip And Bde Determinationmentioning

confidence: 98%

Section: Stability Of the 4-membered Ring Analoguesmentioning

confidence: 99%

Design principles for α-tocopherol analogues

et al. 2006

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“…HWHM life-time broadening of Γ g ′ = 0.05 eV 6 for the valence-excited states and Γ e = 0.075 eV 67 for the C1s core-excited states are used. In the gas phase, the experimental first ionization energy of furan is 8.99 eV, 68 and the C1s ionization potential is 290.33 (C β ) and 291.60 eV (C α ). 28 We only consider the bound states.…”

Section: Computational Detailsmentioning

confidence: 99%

Multiple Core and Vibronic Coupling Effects in Attosecond Stimulated X-Ray Raman Spectroscopy

Hua

Biggs

Zhang

et al. 2013

J. Chem. Theory Comput.

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Attosecond Stimulated X-ray Raman Spectroscopy (SXRS) is a promising technique for investigating molecular electronic structure and photochemical processes with high spatial and temporal resolution. We present a theoretical study of SXRS from multiple core excitation sites of the same element. Two issues are addressed: interference between pathways contributing the signals from different sites; and how nuclear vibrations influence the signals. Taking furan as a model system, which contains two types of carbons Cα and Cβ, we performed time-dependent density functional theory calculations and computed the SXRS signals with two pulses tuned at the carbon K-edge. Our simulations demonstrate that the SXRS signal from the Cα and Cβ sites are non-additive, owing to the significant mixed contributions (Cα 1s excitations by the pump pulse followed by Cβ 1s excitations by the probe, or vice verse). Harmonic vibrations linearly coupled to the electronic transitions are incorporated using the cumulant expansion. The nuclei act as a bath for electronic transitions which accelerate the decay of time-domain signal. The frequency-domain spectrum is modified by a small red shift and high-resolution fine-structure features are introduced.

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“…Photoelectron spectroscopy can be used to determine the stabilization energy of the lone pair in the family of five-membered heterocycles with divalent atoms. As seen in Table , all of the lone-pair ionization energy values are higher than are those for the corresponding tetrahydro derivatives, and this provides a measure of the interaction of the lone pair with the π-system. It is the interaction with the unoccupied orbitals, rather than with the occupied orbitals, that is responsible for aromatic stabilization, and indeed thiophene, accepted to be the most aromatic compound of this series, has the largest lone pair stabilization energy.…”

mentioning

confidence: 96%

Phospholes with Reduced Pyramidal Character from Steric Crowding. 2. Photoelectron Spectral Evidence for Some Electron Delocalization in 1-(2,4-Di-tert-butyl-6-methylphenyl)-3-methylphosphole

1996

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Photoelectron spectroscopy has been explored as a tool to measure the flattening of the phosphorus pyramid in a phosphole as caused by a large, sterically demanding P-substituent. Earlier PE spectra had shown no difference in ionization energies (IE) for simple phospholes and their tetrahydro derivatives (both around 8.0-8.45 eV). Calculations of the Koopmans IE at the Hartree-Fock 6-31G level for 1-methylphospholane showed that, as is known for nitrogen, planarization at phosphorus markedly reduced the ionization energy value (8.74 to 6.29 eV). A reduction in IE also occurred on planarizing 1-methylphosphole, but to a lesser extent, being offset by increased electron delocalization (8.93 to 7.16 eV). This suggests that experimental comparison of IE for the unsaturated and saturated systems could be used to detect the presence of electron delocalization in the former. The IE experimentally determined for the crowded 1-(2,4-di-tert-butyl-6-methylphenyl)-3-methylphosphole was 7.9 eV, the lowest ever recorded for a phosphole. The corresponding phospholane had IE 7.55 eV. The difference in the values is attributed to electron delocalization in the phosphole. Calculations performed on the related model 1-(2-tert-butyl-4,6-dimethylphenyl)phosphole showed that the P-substituent adopted an angle of 55.7 degrees (DFT/6-31G level; 57.6 degrees at the HF/6-31 level) with respect to the C(2)-P-C(5) plane (for P-phenyl, 67.1 degrees and 68.3 degrees, respectively).

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Ionization energies of selenophen, tellurophen and some of their derivatives

Cited by 41 publications

References 5 publications

Design principles for α-tocopherol analogues

Design principles for α-tocopherol analogues

Multiple Core and Vibronic Coupling Effects in Attosecond Stimulated X-Ray Raman Spectroscopy

Phospholes with Reduced Pyramidal Character from Steric Crowding. 2. Photoelectron Spectral Evidence for Some Electron Delocalization in 1-(2,4-Di-tert-butyl-6-methylphenyl)-3-methylphosphole

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