The Vitamin E Radical Probed by Anion Photoelectron Imaging

Anstöter, Cate S.; West, Christopher W.; Bull, James N.; Verlet, Jan R. R.

doi:10.1021/acs.jpcb.6b05271

Cited by 13 publications

(17 citation statements)

References 51 publications

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“…This direct detachment In addition to the direct detachment features, spectral broadening is observed for all the anions, where photoelectron signal is observed at lower eKE than the direct detachment peak. Such shifts have been observed in the photoelectron spectra of many anionic species, 39 Additionally, the cross-section of excitation to the resonance appears to be larger for the latter two as evidenced by the larger proportion of photoelectrons lost from the autodetachment channel than from the direct channel leaving the neutral in the D 1 state. The experimental data allows key properties of the phenolate derivatives to be determined.…”

Section: Resultsmentioning

confidence: 72%

Chromophores of chromophores: a bottom-up Hückel picture of the excited states of photoactive proteins

Anstöter

Dean

Verlet

2017

Phys. Chem. Chem. Phys.

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Citation for published item:enst¤ oterD gte F nd henD ghrlie F nd erletD tn F F @PHIUA 9ghromophores of hromophores X ottomEup r¤ ukel piture of the exited sttes of phototive proteinsF9D hysil hemistry hemil physisFD IW @RRAF ppF PWUUPEPWUUWF Further information on publisher's website: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Here, we present a reductionist approach to gain fundamental insight into the evolution of electronic structure as the chromophore increases in complexity from phenolate to that in GFP. Using frequency-and angle-resolved photoelectron spectroscopy, in combination with electronic structure theory, the onset of excited states that are responsible for the characteristic spectroscopic features in biochromophores are determined. A comprehensive, yet intuitive picture of the effect of phenolate functionalisation is developed based on simple Hückel theory. Specifically, the first two bright excited states can be constructed from a linear combination of molecular orbitals localised on the phenolate and para-substituent groups. This essential interaction is first observed for p-vinyl-phenolate. This bottom-up approach offers a readily accessible framework for the design of photoactive chromophores.

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Section: Resultsmentioning

confidence: 72%

Chromophores of chromophores: a bottom-up Hückel picture of the excited states of photoactive proteins

Anstöter

Dean

Verlet

2017

Phys. Chem. Chem. Phys.

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“…In the absence of continuum resonances, photoelectrons with different anisotropies can be assumed to arise from detachment from anion molecular orbitals of different electronic character and, in general, a negative β 2 can be attributed to photodetachment from an orbital with p or π character and a positive β 2 can be attributed to photoionisation from an orbital with s or σ character. PADs can be very sensitive to continuum resonances and molecular conformations and thus provide an informative additional probe of electronic and molecular structure [39,40].…”

Section: Experimental Considerationsmentioning

confidence: 99%

Anion photoelectron spectroscopy of protein chromophores

Henley

Fielding

2019

International Reviews in Physical Chemistry

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Photoactive proteins that efficiently and selectively transfer light energy into a physical response are ubiquitous in nature. The small molecule chromophores that lie at the heart of these processes often exist as closed-shell anions following deprotonation in proton-transfer reactions. This review highlights the important role that anion photoelectron spectroscopy, combined with computational chemistry calculations, is playing in improving our understanding of the electronic structure and relaxation dynamics of these protein chromophores. We discuss key aspects of anion photoelectron spectroscopy. We then review recent anion photoelectron spectroscopy studies of the deprotonated chromophore anions found in green fluorescent protein (GFP), photoactive yellow protein (PYP) and the deprotonated oxyluciferin anion found in the luciferase enzyme.

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“…30,31 The excited states of pDNBwere calculated using an active space of 12 valence π-orbitals and 15 electrons. In order to include all states within our experimental range, we employed the XMCQDPT2 [11]/SA(9)-CASSCF (15,12) method with a reference space spanned by 11 CASCI wavefunctions, which were obtained through complete active space self-consistent field (CASSCF) calculations using a state averaging procedure (SA). A DFT/PBE0-based one-electron Fock-type matrix was used to obtain energies of all CASSCF semi-canonical orbitals used in perturbation theory.…”

Section: Computationalmentioning

confidence: 99%

“…[6][7][8][9] We have recently developed an optical variant in which the photoelectron (PE) images are acquired as a function of photon energy (hv). [10][11][12] Here, we present such a 2D PE imaging study and employ highlevel electronic structure calculations to unravel the information-rich spectra of the para-dinitrobenzene radical anion (pDNB − ).…”

Section: Introductionmentioning

confidence: 99%

Electronic structure of the para-dinitrobenzene radical anion: a combined 2D photoelectron imaging and computational study

Anstöter

Gartmann

Stanley

et al. 2018

Phys. Chem. Chem. Phys.

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The para-dinitrobenzene radical anion has been studied by 2D photoelectron imaging within the energy range of 2.5 eV above the detachment threshold. Supporting electronic structure calculations at the XMCQDPT2 level of the excited states and resonances are presented. The direct photodetachment channel has been observed and modelled, and yields an electron affinity of 1.99 ± 0.01 eV. In addition to the direct channel, evidence of resonances is observed. These resonances, which are symmetry allowed for photoexcitation from the ground state and of Feshbach types with respect to the open continuum, result in fast internal conversion to bound electronic states, followed by statistical electron emission observed at very low kinetic energies as well as dissociation of the nitrite anion. The latter is seen in the photoelectron spectra, which can be modelled as a combination of direct detachment from the para-dinitrobenzene and nitrite anions. An additional dimension has been offered by the 2D photoelectron angular distribution that is particularly sensitive to a mechanism of electron detachment, allowing us to confidently interpret the production of the nitrite anion photofragment.

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The Vitamin E Radical Probed by Anion Photoelectron Imaging

Cited by 13 publications

References 51 publications

Chromophores of chromophores: a bottom-up Hückel picture of the excited states of photoactive proteins

Chromophores of chromophores: a bottom-up Hückel picture of the excited states of photoactive proteins

Anion photoelectron spectroscopy of protein chromophores

Electronic structure of the para-dinitrobenzene radical anion: a combined 2D photoelectron imaging and computational study

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