1
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Navarro Navarrete JE, Bull JN, Cederquist H, Indrajith S, Ji M, Schmidt HT, Zettergren H, Zhu B, Stockett MH. Experimental radiative cooling rates of a polycyclic aromatic hydrocarbon cation. Faraday Discuss 2023; 245:352-367. [PMID: 37317671 DOI: 10.1039/d3fd00005b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
Several small Polycyclic Aromatic Hydrocarbons (PAHs) have been identified recently in the Taurus Molecular Cloud (TMC-1) using radio telescope observations. Reproducing the observed abundances of these molecules has been a challenge for astrochemical models. Rapid radiative cooling of PAHs by Recurrent Fluorescence (RF), the emission of optical photons from thermally populated electronically excited states, has been shown to efficiently stabilize small PAHs following ionization, augmenting their resilience in astronomical environments and helping to rationalize their observed high abundances. Here, we use a novel method to experimentally determine the radiative cooling rate of the cation of 1-cyanonaphthalene (C10H7CN, 1-CNN), the neutral species of which has been identified in TMC-1. Laser-induced dissociation rates and kinetic energy release distributions of 1-CNN cations isolated in a cryogenic electrostatic ion-beam storage ring are analysed to track the time evolution of the vibrational energy distribution of the initially hot ion ensemble as it cools. The measured cooling rate is in good agreement with the previously calculated RF rate coefficient. Improved measurements and models of the RF mechanism are needed to interpret astronomical observations and refine predictions of the stabilities of interstellar PAHs.
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Affiliation(s)
| | - James N Bull
- School of Chemistry, University of East Anglia, Norwich, UK
| | | | | | - MingChao Ji
- Department of Physics, Stockholm University, Stockholm, Sweden.
| | | | | | - Boxing Zhu
- Department of Physics, Stockholm University, Stockholm, Sweden.
| | - Mark H Stockett
- Department of Physics, Stockholm University, Stockholm, Sweden.
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2
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Ashworth EK, Kao MH, Anstöter CS, Riesco-Llach G, Blancafort L, Solntsev KM, Meech SR, Verlet JRR, Bull JN. Alkylated green fluorescent protein chromophores: dynamics in the gas phase and in aqueous solution. Phys Chem Chem Phys 2023; 25:23626-23636. [PMID: 37649445 DOI: 10.1039/d3cp03250g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Fluorescent labelling of macromolecular samples, including using the green fluorescent protein (GFP), has revolutionised the field of bioimaging. The ongoing development of fluorescent proteins require a detailed understanding of the photophysics of the biochromophore, and how chemical derivatisation influences the excited state dynamics. Here, we investigate the photophysical properties associated with the S1 state of three alkylated derivatives of the chromophore in GFP, in the gas phase using time-resolved photoelectron imaging, and in water using femtosecond fluorescence upconversion. The gas-phase lifetimes (1.6-10 ps), which are associated with the intrinsic (environment independent) dynamics, are substantially longer than the lifetimes in water (0.06-3 ps), attributed to stabilisation of both twisted intermediate structures and conical intersection seams in the condensed phase. In the gas phase, alkylation on the 3 and 5 positions of the phenyl ring slows the dynamics due to inertial effects, while a 'pre-twist' of the methine bridge through alkylation on the 2 and 6 positions significantly shortens the excited state lifetimes. Formation of a minor, long-lived (≫ 40 ps) excited state population in the gas phase is attributed to intersystem crossing to a triplet state, accessed because of a T1/S1 degeneracy in the so-called P-trap potential energy minimum associated with torsion of the single-bond in the bridging unit connecting to the phenoxide ring. A small amount of intersystem crossing is supported through TD-DFT molecular dynamics trajectories and MS-CASPT2 calculations. No such intersystem crossing occurs in water at T = 300 K or in ethanol at T ≈ 77 K, due to a significantly altered potential energy surface and P-trap geometry.
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Affiliation(s)
- Eleanor K Ashworth
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK.
| | - Min-Hsien Kao
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK.
| | - Cate S Anstöter
- Department of Chemistry, Durham University, Durham, DH1 3LE, UK
| | - Gerard Riesco-Llach
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/M.A. Capmany 69, 17003 Girona, Spain
| | - Lluís Blancafort
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/M.A. Capmany 69, 17003 Girona, Spain
| | - Kyril M Solntsev
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Stephen R Meech
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK.
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham, DH1 3LE, UK
| | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK.
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3
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Ashworth EK, Dezalay J, Ryan CRM, Ieritano C, Hopkins WS, Chambrier I, Cammidge AN, Stockett MH, Noble JA, Bull JN. Protomers of the green and cyan fluorescent protein chromophores investigated using action spectroscopy. Phys Chem Chem Phys 2023. [PMID: 37465988 DOI: 10.1039/d3cp02661b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
The photophysics of biochromophore ions often depends on the isomeric or protomeric distribution, yet this distribution, and the individual isomer contributions to an action spectrum, can be difficult to quantify. Here, we use two separate photodissociation action spectroscopy instruments to record electronic spectra for protonated forms of the green (pHBDI+) and cyan (Cyan+) fluorescent protein chromophores. One instrument allows for cryogenic (T = 40 ± 10 K) cooling of the ions, while the other offers the ability to perform protomer-selective photodissociation spectroscopy. We show that both chromophores are generated as two protomers when using electrospray ionisation, and that the protomers have partially overlapping absorption profiles associated with the S1 ← S0 transition. The action spectra for both species span the 340-460 nm range, although the spectral onset for the pHBDI+ protomer with the proton residing on the carbonyl oxygen is red-shifted by ≈40 nm relative to the lower-energy imine protomer. Similarly, the imine and carbonyl protomers are the lowest energy forms of Cyan+, with the main band for the carbonyl protomer red-shifted by ≈60 nm relative to the lower-energy imine protomer. The present strategy for investigating protomers can be applied to a wide range of other biochromophore ions.
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Affiliation(s)
- Eleanor K Ashworth
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Jordan Dezalay
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | | | - Christian Ieritano
- Department of Chemistry, University of Waterloo, Waterloo N2L 3G1, Canada
| | - W Scott Hopkins
- Department of Chemistry, University of Waterloo, Waterloo N2L 3G1, Canada
| | - Isabelle Chambrier
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Andrew N Cammidge
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Mark H Stockett
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | | | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
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4
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Bull JN, Bolognesi P, Anstöter CS, Ashworth EK, Navarro Navarrete JE, Zhu B, Richter R, Pal N, Chiarinelli J, Avaldi L, Zettergren H, Stockett MH. Autoionization from the plasmon resonance in isolated 1-cyanonaphthalene. J Chem Phys 2023; 158:241101. [PMID: 37347125 DOI: 10.1063/5.0153058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 06/05/2023] [Indexed: 06/23/2023] Open
Abstract
Polycyclic aromatic hydrocarbons have widely been conjectured to be ubiquitous in space, as supported by the recent discovery of two isomers of cyanonaphthalene, indene, and 2-cyanoindene in the Taurus molecular cloud-1 using radioastronomy. Here, the photoionization dynamics of 1-cyanonaphthalene (1-CNN) are investigated using synchrotron radiation over the hν = 9.0-19.5 eV range, revealing that prompt autoionization from the plasmon resonance dominates the photophysics for hν = 11.5-16.0 eV. Minimal photo-induced dissociation, whether originating from an excited state impulsive bond rupture or through internal conversion followed by a statistical bond cleavage process, occurs over the microsecond timescale (as limited by the experimental setup). The direct photoionization cross section and photoelectron angular distributions are simulated using an ezDyson model combining Dyson orbitals with Coulomb wave photoejection. When considering these data in conjunction with recent radiative cooling measurements on 1-CNN+, which showed that cations formed with up to 5 eV of internal energy efficiently stabilize through recurrent fluorescence, we conclude that the organic backbone of 1-CNN is resilient to photodestruction by VUV and soft XUV radiation. These dynamics may prove to be a common feature for the survival of small polycyclic aromatic hydrocarbons in space, provided that the cations have a suitable electronic structure to support recurrent fluorescence.
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Affiliation(s)
- James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
- Centre for Photonics and Quantum Science, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Paola Bolognesi
- CNR-Istituto di Struttura della Materia, Area della Ricerca di Roma 1, Rome, Italy
| | - Cate S Anstöter
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Eleanor K Ashworth
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | | | - Boxing Zhu
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | | | - Nitish Pal
- Elettra Sincrotrone Trieste, Trieste, Italy
| | - Jacopo Chiarinelli
- CNR-Istituto di Struttura della Materia, Area della Ricerca di Roma 1, Rome, Italy
| | - Lorenzo Avaldi
- CNR-Istituto di Struttura della Materia, Area della Ricerca di Roma 1, Rome, Italy
| | | | - Mark H Stockett
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
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5
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Lee JWL, Stockett MH, Ashworth EK, Navarro Navarrete JE, Gougoula E, Garg D, Ji M, Zhu B, Indrajith S, Zettergren H, Schmidt HT, Bull JN. Cooling dynamics of energized naphthalene and azulene radical cations. J Chem Phys 2023; 158:2887564. [PMID: 37125715 DOI: 10.1063/5.0147456] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/12/2023] [Indexed: 05/02/2023] Open
Abstract
Naphthalene and azulene are isomeric polycyclic aromatic hydrocarbons (PAHs) and are topical in the context of astrochemistry due to the recent discovery of substituted naphthalenes in the Taurus Molecular Cloud-1 (TMC-1). Here, the thermal- and photo-induced isomerization, dissociation, and radiative cooling dynamics of energized (vibrationally hot) naphthalene (Np+) and azulene (Az+) radical cations, occurring over the microsecond to seconds timescale, are investigated using a cryogenic electrostatic ion storage ring, affording "molecular cloud in a box" conditions. Measurement of the cooling dynamics and kinetic energy release distributions for neutrals formed through dissociation, until several seconds after hot ion formation, are consistent with the establishment of a rapid (sub-microsecond) Np+ ⇌ Az+ quasi-equilibrium. Consequently, dissociation by C2H2-elimination proceeds predominantly through common Az+ decomposition pathways. Simulation of the isomerization, dissociation, recurrent fluorescence, and infrared cooling dynamics using a coupled master equation combined with high-level potential energy surface calculations [CCSD(T)/cc-pVTZ], reproduce the trends in the measurements. The data show that radiative cooling via recurrent fluorescence, predominately through the Np+ D0 ← D2 transition, efficiently quenches dissociation for vibrational energies up to ≈1 eV above dissociation thresholds. Our measurements support the suggestion that small cations, such as naphthalene, may be more abundant in space than previously thought. The strategy presented in this work could be extended to fingerprint the cooling dynamics of other PAH ions for which isomerization is predicted to precede dissociation.
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Affiliation(s)
- Jason W L Lee
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Mark H Stockett
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Eleanor K Ashworth
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | | | - Eva Gougoula
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Diksha Garg
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - MingChao Ji
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Boxing Zhu
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | | | | | - Henning T Schmidt
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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6
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Marlton SJP, Buntine JT, Watkins P, Liu C, Jacovella U, Carrascosa E, Bull JN, Bieske EJ. Probing Colossal Carbon Rings. J Phys Chem A 2023; 127:1168-1178. [PMID: 36703560 DOI: 10.1021/acs.jpca.2c07068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Carbon aggregates containing between 10 and 30 atoms preferentially arrange themselves as planar rings. To learn more about this exotic allotrope of carbon, electronic spectra are measured for even cyclo[n]carbon radical cations (C14+-C36+) using two-color photodissociation action spectroscopy. To eliminate spectral contributions from other isomers, the target cyclo[n]carbon radical cations are isomer-selected using a drift tube ion mobility spectrometer prior to spectroscopic interrogation. The electronic spectra exhibit sharp transitions spanning the visible and near-infrared spectral regions with the main absorption band shifting progressively to longer wavelength by ≈100 nm for every additional two carbon atoms. This behavior is rationalized with a Hückel theory model describing the energies of the in-plane and out-of-plane π orbitals. Photoexcitation of smaller carbon rings leads preferentially to neutral C3 and C5 loss, whereas rings larger than C24+ tend to also decompose into two smaller rings, which, when possible, have aromatic stability. Generally, the observed charged photofragments correspond to low energy fragment pairs, as predicted by density functional theory calculations (CAM-B3LYP-D3(BJ)/cc-pVDZ). Using action spectroscopy it is confirmed that C14+ and C18+ photofragments from C28+ rings have cyclic structures.
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Affiliation(s)
- Samuel J P Marlton
- School of Chemistry, The University of Melbourne, Victoria, Australia3010
| | - Jack T Buntine
- School of Chemistry, The University of Melbourne, Victoria, Australia3010
| | - Patrick Watkins
- School of Chemistry, The University of Melbourne, Victoria, Australia3010
| | - Chang Liu
- School of Chemistry, The University of Melbourne, Victoria, Australia3010
| | - Ugo Jacovella
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405Orsay, France
| | - Eduardo Carrascosa
- Bruker Daltonics GmbH & Co. KG, Fahrenheitstrasse 4, 28359Bremen, Germany
| | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, NorwichNR4 7TJ, United Kingdom
| | - Evan J Bieske
- School of Chemistry, The University of Melbourne, Victoria, Australia3010
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7
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Stockett MH, Bull JN, Cederquist H, Indrajith S, Ji M, Navarro Navarrete JE, Schmidt HT, Zettergren H, Zhu B. Efficient stabilization of cyanonaphthalene by fast radiative cooling and implications for the resilience of small PAHs in interstellar clouds. Nat Commun 2023; 14:395. [PMID: 36693859 PMCID: PMC9873784 DOI: 10.1038/s41467-023-36092-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 01/13/2023] [Indexed: 01/25/2023] Open
Abstract
After decades of searching, astronomers have recently identified specific Polycyclic Aromatic Hydrocarbons (PAHs) in space. Remarkably, the observed abundance of cyanonaphthalene (CNN, C10H7CN) in the Taurus Molecular Cloud (TMC-1) is six orders of magnitude higher than expected from astrophysical modeling. Here, we report unimolecular dissociation and radiative cooling rate coefficients of the 1-CNN isomer in its cationic form. These results are based on measurements of the time-dependent neutral product emission rate and kinetic energy release distributions produced from an ensemble of internally excited 1-CNN+ studied in an environment similar to that in interstellar clouds. We find that Recurrent Fluorescence - radiative relaxation via thermally populated electronic excited states - efficiently stabilizes 1-CNN+, owing to a large enhancement of the electronic transition probability by vibronic coupling. Our results help explain the anomalous abundance of CNN in TMC-1 and challenge the widely accepted picture of rapid destruction of small PAHs in space.
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Affiliation(s)
- Mark H. Stockett
- grid.10548.380000 0004 1936 9377Department of Physics, Stockholm University, Stockholm, Sweden
| | - James N. Bull
- grid.8273.e0000 0001 1092 7967School of Chemistry, University of East Anglia, Norwich, United Kingdom
| | - Henrik Cederquist
- grid.10548.380000 0004 1936 9377Department of Physics, Stockholm University, Stockholm, Sweden
| | - Suvasthika Indrajith
- grid.10548.380000 0004 1936 9377Department of Physics, Stockholm University, Stockholm, Sweden
| | - MingChao Ji
- grid.10548.380000 0004 1936 9377Department of Physics, Stockholm University, Stockholm, Sweden
| | | | - Henning T. Schmidt
- grid.10548.380000 0004 1936 9377Department of Physics, Stockholm University, Stockholm, Sweden
| | - Henning Zettergren
- grid.10548.380000 0004 1936 9377Department of Physics, Stockholm University, Stockholm, Sweden
| | - Boxing Zhu
- grid.10548.380000 0004 1936 9377Department of Physics, Stockholm University, Stockholm, Sweden
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8
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Addison K, Roy P, Bressan G, Skudaite K, Robb J, Bulman Page PC, Ashworth EK, Bull JN, Meech SR. Photophysics of the red-form Kaede chromophore. Chem Sci 2023; 14:3763-3775. [PMID: 37035701 PMCID: PMC10074405 DOI: 10.1039/d3sc00368j] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/08/2023] [Indexed: 03/18/2023] Open
Abstract
The chromophore responsible for colour switching in the optical highlighting protein Kaede has unexpectedly complicated excited state dynamics, which are measured and analysed here. This will inform the development of new imaging proteins.
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Affiliation(s)
- Kiri Addison
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Palas Roy
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Giovanni Bressan
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Karolina Skudaite
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Josh Robb
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | | | - Eleanor K. Ashworth
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - James N. Bull
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Stephen R. Meech
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
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9
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Ashworth EK, Langeland J, Stockett MH, Lindkvist TT, Kjær C, Bull JN, Nielsen SB. Cryogenic Fluorescence Spectroscopy of Ionic Fluorones in Gaseous and Condensed Phases: New Light on Their Intrinsic Photophysics. J Phys Chem A 2022; 126:9553-9563. [PMID: 36529970 DOI: 10.1021/acs.jpca.2c07231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Fluorescence spectroscopy of gas-phase ions generated through electrospray ionization is an emerging technique able to probe intrinsic molecular photophysics directly without perturbations from solvent interactions. While there is ample scope for the ongoing development of gas-phase fluorescence techniques, the recent expansion into low-temperature operating conditions accesses a wealth of data on intrinsic fluorophore photophysics, offering enhanced spectral resolution compared with room-temperature measurements, without matrix effects hindering the excited-state dynamics. This perspective reviews current progress on understanding the photophysics of anionic fluorone dyes, which exhibit an unusually large Stokes shift in the gas phase, and discusses how comparison of gas- and condensed-phase fluorescence spectra can fingerprint structural dynamics. The capacity for temperature-dependent measurements of both fluorescence emission and excitation spectra helps establish the foundation for the use of fluorone dyes as fluorescent tags in macromolecular structure determination. We suggest ideas for technique development.
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Affiliation(s)
- Eleanor K Ashworth
- School of Chemistry, University of East Anglia, NorwichNR4 7TJ, United Kingdom
| | - Jeppe Langeland
- Department of Physics and Astronomy, Aarhus University, Aarhus8000, Denmark
| | - Mark H Stockett
- Department of Physics, Stockholm University, SE-10691Stockholm, Sweden
| | | | - Christina Kjær
- Department of Physics and Astronomy, Aarhus University, Aarhus8000, Denmark
| | - James N Bull
- School of Chemistry, University of East Anglia, NorwichNR4 7TJ, United Kingdom
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10
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Zhu B, Bull JN, Navarro Navarrete JE, Schmidt-May AF, Cederquist H, Schmidt HT, Zettergren H, Stockett MH. Radiative cooling of polyyne anions: C 4H - and C 6H -. J Chem Phys 2022; 157:174308. [DOI: 10.1063/5.0111144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The time-dependent photodetachment action spectra of the linear hydrocarbon anions C4H- and C6H- are investigated using the cryogenic electrostatic ion storage ring DESIREE. Radiative cooling characteristics of the ions on the millisecond to second timescale are probed by monitoring changes in the spectra as the ions cool by spontaneous infrared (IR) emission. A simple harmonic cascade (SHC) model is used to model the cooling processes. The cooling rates, extracted using Non-negative Matrix Factorization (NMF), are fit with 1/e lifetimes of 19 {plus minus} 2 s and 3.0 {plus minus} 0.2 s for C4H- and C6H-, respectively. For C4H-, the adiabatic detachment energy is determined from the cold ions' photodetachment spectra to be 3.45 {plus minus} 0.02 eV. The photodetachment spectrum and the ultraslow radiative cooling dynamics interpreted in the present work provide important data for understanding the thermal cooling properties of linear hydrocarbon anions and for refining the formation and destruction processes of these anions in astrochemical models.
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Affiliation(s)
- Boxing Zhu
- Department of Physics, Stockholm University Department of Physics, Sweden
| | - James N Bull
- School of Chemistry, University of East Anglia, United Kingdom
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11
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Ashworth E, Coughlan NJA, Hopkins WS, Bieske EJ, Bull JN. Excited-State Barrier Controls E → Z Photoisomerization in p-Hydroxycinnamate Biochromophores. J Phys Chem Lett 2022; 13:9028-9034. [PMID: 36149746 PMCID: PMC9549896 DOI: 10.1021/acs.jpclett.2c02613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
Molecules based on the deprotonated p-hydroxycinnamate moiety are widespread in nature, including serving as UV filters in the leaves of plants and as the biochromophore in photoactive yellow protein. The photophysical behavior of these chromophores is centered around a rapid E → Z photoisomerization by passage through a conical intersection seam. Here, we use photoisomerization and photodissociation action spectroscopies with deprotonated 4-hydroxybenzal acetone (pCK-) to characterize a wavelength-dependent bifurcation between electron autodetachment (spontaneous ejection of an electron from the S1 state because it is situated in the detachment continuum) and E → Z photoisomerization. While autodetachment occurs across the entire S1(ππ*) band (370-480 nm), E → Z photoisomerization occurs only over a blue portion of the band (370-430 nm). No E → Z photoisomerization is observed when the ketone functional group in pCK- is replaced with an ester or carboxylic acid. The wavelength-dependent bifurcation is consistent with potential energy surface calculations showing that a barrier separates the Franck-Condon region from the E → Z isomerizing conical intersection. The barrier height, which is substantially higher in the gas phase than in solution, depends on the functional group and governs whether E → Z photoisomerization occurs more rapidly than autodetachment.
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Affiliation(s)
- Eleanor
K. Ashworth
- School
of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Neville J. A. Coughlan
- Department
of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- WaterMine
Innovation, Inc., Waterloo, Ontario N0B 2T0, Canada
| | - W. Scott Hopkins
- Department
of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- WaterMine
Innovation, Inc., Waterloo, Ontario N0B 2T0, Canada
| | - Evan J. Bieske
- School
of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | - James N. Bull
- School
of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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12
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Marlton SJP, Buntine JT, Liu C, Watkins P, Jacovella U, Carrascosa E, Bull JN, Bieske EJ. Disentangling Electronic Spectra of Linear and Cyclic Hydrogenated Carbon Cluster Cations, C 2n+1H + ( n = 3–10). J Phys Chem A 2022; 126:6678-6685. [DOI: 10.1021/acs.jpca.2c05051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Samuel J. P. Marlton
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
| | - Jack T. Buntine
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
| | - Chang Liu
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
| | - Patrick Watkins
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
| | - Ugo Jacovella
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, 91405 Orsay, France
| | - Eduardo Carrascosa
- Bruker Daltonics GmbH & Co. KG, Fahrenheitstrasse 4, 28359 Bremen, Germany
| | - James N. Bull
- School of Chemistry, University of East Anglia, Norwich Research Park, NR4 7TJ Norwich, U.K
| | - Evan J. Bieske
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
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13
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Zhu B, Bull JN, Ji M, Zettergren H, Stockett MH. Radiative cooling rates of substituted PAH ions. J Chem Phys 2022; 157:044303. [DOI: 10.1063/5.0089687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The unimolecular dissociation and infrared radiative cooling rates of cationic 1-hydroxypyrene (OHPyr$^+$, \ce{C16H10O+}) and 1-bromopyrene (BrPyr$^+$, \ce{C16H9Br+}) are measured using a cryogenic electrostatic \rev{ion beam} storage ring. A novel numerical approach is developed to analyze the time dependence of the dissociation rate and to determine the absolute scaling of the radiative cooling rate coefficient. The model results show that radiative cooling competes with dissociation below the critical total vibrational energies \revv{$E_c=5.39(1)$}~eV for OHPyr$^+$ and \revv{5.90(1)}~eV for BrPyr$^+$. These critical energies and implications for radiative cooling dynamics are important for astrochemical models concerned with energy dissipation and molecular lifecycles. The methods presented extend the utility of storage ring experiments on astrophysically relevant ions.
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Affiliation(s)
| | - James N Bull
- School of Chemistry, University of East Anglia, United Kingdom
| | - MingChao Ji
- Stockholm University Department of Physics, Sweden
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14
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Buntine JT, Carrascosa E, Bull JN, Muller G, Jacovella U, Glasson CR, Vamvounis G, Bieske EJ. Photo-induced 6π-electrocyclisation and cycloreversion of isolated dithienylethene anions. Phys Chem Chem Phys 2022; 24:16628-16636. [PMID: 35766319 DOI: 10.1039/d2cp01240e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The diarylethene chromophore is commonly used in light-triggered molecular switches. The chromophore undergoes reversible 6π-electrocyclisation (ring closing) and cycloreversion (ring opening) reactions upon exposure to UV and visible light, respectively, providing bidirectional photoswitching. Here, we investigate the gas-phase photoisomerisation of meta- (m) and para- (p) substituted dithienylethene carboxylate anions (DTE-) using tandem ion mobility mass spectrometry coupled with laser excitation. The ring-closed forms of p-DTE- and m-DTE- are found to undergo cycloreversion in the gas phase with maximum responses associated with bands in the visible (λmax ≈ 600 nm) and the ultraviolet (λmax ≈ 360 nm). The ring-open p-DTE- isomer undergoes 6π-electrocyclisation in the ultraviolet region at wavelengths shorter than 350 nm, whereas no evidence is found for the corresponding electrocyclisation of ring-open m-DTE-, a situation attributed to the fact that the antiparallel geometry required for electrocyclisation of m-DTE- is energetically disfavoured. This highlights the influence of the carboxylate substitution position on the photochemical properties of DTE molecules. We find no evidence for the formation in the gas phase of the undesirable cyclic byproduct, which causes fatigue of DTE photoswitches in solution.
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Affiliation(s)
- Jack T Buntine
- School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Eduardo Carrascosa
- Bruker Daltonics GmbH & Co. KG, Fahrenheitstrasse 4, 28359 Bremen, Germany
| | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK
| | - Giel Muller
- School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Ugo Jacovella
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France
| | - Christopher R Glasson
- Environmental Research Institute, School of Science, University of Waikato, Tauranga, 3110, New Zealand
| | - George Vamvounis
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - Evan J Bieske
- School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia.
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15
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Stockett MH, Bull JN, Schmidt HT, Zettergren H. Statistical vibrational autodetachment and radiative cooling rates of para-benzoquinone. Phys Chem Chem Phys 2022; 24:12002-12010. [PMID: 35535575 DOI: 10.1039/d2cp00490a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We report measurements of the statistical vibrational autodetachment (VAD, also called thermionic emission) and radiative cooling rates of isolated para-benzoquinone (pBQ, C6H4O2) radical anions using the cryogenic electrostatic ion storage ring facility DESIREE. The results are interpreted using master equation simulations with rate coefficients calculated using statistical detailed balance theory. The VAD rate is determined by measuring the time-dependent yield of neutral pBQ due to spontaneous electron emission from a highly-excited ensemble of anions formed in an electron-attachment ion source. Competition with radiative cooling quenches the VAD rate after a critical time of τc = 11.00(5) ms. Master equation simulations which reproduce the VAD yield provide an estimate of the initial effective vibrational temperature of the ions of 1100(20) K, and provide insight into the anion formation scenario. A second measurement of the radiative cooling rate of pBQ- stored for up to 0.5 s was achieved using time-dependent photodetachment action spectroscopy across the 2Au ← 2B2g and 2B2u ← 2B2g transitions. The rate at which hot-band contributions fade from the action spectrum is quantified by non-negative matrix factorisation. This is found to be commensurate with the average vibrational energy extracted from the simulations, with 1/e lifetimes of 0.16(3) s and 0.1602(7) s, respectively. Implications for astrochemistry are discussed.
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Affiliation(s)
- Mark H Stockett
- Department of Physics, Stockholm University, Stockholm, Sweden.
| | - James N Bull
- School of Chemistry, University of East Anglia, Norwich, UK
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16
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Buntine JT, Carrascosa E, Bull JN, Jacovella U, Cotter MI, Watkins P, Liu C, Scholz MS, Adamson BD, Marlton SJP, Bieske EJ. An ion mobility mass spectrometer coupled with a cryogenic ion trap for recording electronic spectra of charged, isomer-selected clusters. Rev Sci Instrum 2022; 93:043201. [PMID: 35489918 DOI: 10.1063/5.0085680] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
Infrared and electronic spectra are indispensable for understanding the structural and energetic properties of charged molecules and clusters in the gas phase. However, the presence of isomers can potentially complicate the interpretation of spectra, even if the target molecules or clusters are mass-selected beforehand. Here, we describe an instrument for spectroscopically characterizing charged molecular clusters that have been selected according to both their isomeric form and their mass-to-charge ratio. Cluster ions generated by laser ablation of a solid sample are selected according to their collision cross sections with helium buffer gas using a drift tube ion mobility spectrometer and their mass-to-charge ratio using a quadrupole mass filter. The mobility- and mass-selected target ions are introduced into a cryogenically cooled, three-dimensional quadrupole ion trap where they are thermalized through inelastic collisions with an inert buffer gas (He or He/N2 mixture). Spectra of the molecular ions are obtained by tagging them with inert atoms or molecules (Ne and N2), which are dislodged following resonant excitation of an electronic transition, or by photodissociating the cluster itself following absorption of one or more photons. An electronic spectrum is generated by monitoring the charged photofragment yield as a function of wavelength. The capacity of the instrument is illustrated with the resonance-enhanced photodissociation action spectra of carbon clusters (Cn +) and polyacetylene cations (HC2nH+) that have been selected according to the mass-to-charge ratio and collision cross section with He buffer gas and of mass-selected Au2 + and Au2Ag+ clusters.
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Affiliation(s)
- Jack T Buntine
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Eduardo Carrascosa
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - James N Bull
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Ugo Jacovella
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Mariah I Cotter
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Patrick Watkins
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Chang Liu
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Michael S Scholz
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Brian D Adamson
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Samuel J P Marlton
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Evan J Bieske
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
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17
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Ashworth EK, Stockett MH, Kjær C, Bulman Page PC, Meech SR, Nielsen SB, Bull JN. Complexation of Green and Red Kaede Fluorescent Protein Chromophores by a Zwitterion to Probe Electrostatic and Induction Field Effects. J Phys Chem A 2022; 126:1158-1167. [PMID: 35138862 DOI: 10.1021/acs.jpca.1c10628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photophysics of green fluorescent protein (GFP) and red Kaede fluorescent protein (rKFP) are defined by the intrinsic properties of the light-absorbing chromophore and its interaction with the protein binding pocket. This work deploys photodissociation action spectroscopy to probe the absorption profiles for a series of synthetic GFP and rKFP chromophores as the bare anions and as complexes with the betaine zwitterion, which is assumed as a model for dipole microsolvation. Electronic structure calculations and energy decomposition analysis using Symmetry-Adapted Perturbation Theory are used to characterize gas-phase structures and complex cohesion forces. The calculations reveal a preponderance for coordination of betaine to the phenoxide deprotonation site predominantly through electrostatic forces. Calculations using the STEOM-DLPNO-CCSD method are able to reproduce absolute and relative vertical excitation energies for the bare anions and anion-betaine complexes. On the other hand, treatment of the betaine molecule with a point-charge model, in which the charges are computed from some common electron density population analysis schemes, show that just electrostatic and point-charge induction interactions are unable to account for the betaine-induced spectral shift. The present methodology could be applied to investigate cluster forces and optical properties in other gas-phase ion-zwitterion complexes.
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Affiliation(s)
- Eleanor K Ashworth
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Mark H Stockett
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Christina Kjær
- Department of Physics and Astronomy, Aarhus University, Aarhus 8000, Denmark
| | - Philip C Bulman Page
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Stephen R Meech
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | | | - James N Bull
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
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18
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Bull JN, Anstöter CS, Stockett MH, Clarke CJ, Gibbard JA, Bieske EJ, Verlet JRR. Nonadiabatic Dynamics between Valence, Nonvalence, and Continuum Electronic States in a Heteropolycyclic Aromatic Hydrocarbon. J Phys Chem Lett 2021; 12:11811-11816. [PMID: 34870432 DOI: 10.1021/acs.jpclett.1c03532] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Internal conversion between valence-localized and dipole-bound states is thought to be a ubiquitous process in polar molecular anions, yet there is limited direct evidence. Here, photodetachment action spectroscopy and time-resolved photoelectron imaging with a heteropolycyclic aromatic hydrocarbon (hetero-PAH) anion, deprotonated 1-pyrenol, is used to demonstrate a subpicosecond (τ1 = 160 ± 20 fs) valence to dipole-bound state internal conversion following excitation of the origin transition of the first valence-localized excited state. The internal conversion dynamics are evident in the photoelectron spectra and in the photoelectron angular distributions (β2 values) as the electronic character of the excited state population changes from valence to nonvalence. The dipole-bound state subsequently decays through mode-specific vibrational autodetachment with a lifetime τ2 = 11 ± 2 ps. These internal conversion and autodetachment dynamics are likely common in molecular anions but difficult to fingerprint due to the transient existence of the dipole-bound state. Potential implications of the present excited state dynamics for interstellar hetero-PAH anion formation are discussed.
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Affiliation(s)
- James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Cate S Anstöter
- Department of Chemistry, Temple University, 1901 N 13th Street, Philadelphia, Pennsylvania 19122, United States
| | - Mark H Stockett
- Department of Physics, Stockholm University, Stockholm SE-106 91, Sweden
| | - Connor J Clarke
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Jemma A Gibbard
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Evan J Bieske
- School of Chemistry, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
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19
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Buntine JT, Cotter MI, Jacovella U, Liu C, Watkins P, Carrascosa E, Bull JN, Weston L, Muller G, Scholz MS, Bieske EJ. Electronic spectra of positively charged carbon clusters-C 2n + (n = 6-14). J Chem Phys 2021; 155:214302. [PMID: 34879679 DOI: 10.1063/5.0070502] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Electronic spectra are measured for mass-selected C2n +(n = 6-14) clusters over the visible and near-infrared spectral range through resonance enhanced photodissociation of clusters tagged with N2 molecules in a cryogenic ion trap. The carbon cluster cations are generated through laser ablation of a graphite disk and can be selected according to their collision cross section with He buffer gas and their mass prior to being trapped and spectroscopically probed. The data suggest that the C2n +(n = 6-14) clusters have monocyclic structures with bicyclic structures becoming more prevalent for C22 + and larger clusters. The C2n + electronic spectra are dominated by an origin transition that shifts linearly to a longer wavelength with the number of carbon atoms and associated progressions involving excitation of ring deformation vibrational modes. Bands for C12 +, C16 +, C20 +, C24 +, and C28 + are relatively broad, possibly due to rapid non-radiative decay from the excited state, whereas bands for C14 +, C18 +, C22 +, and C26 + are narrower, consistent with slower non-radiative deactivation.
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Affiliation(s)
- Jack T Buntine
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Mariah I Cotter
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Ugo Jacovella
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Chang Liu
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Patrick Watkins
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Eduardo Carrascosa
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - James N Bull
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Luke Weston
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Giel Muller
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Michael S Scholz
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Evan J Bieske
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
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20
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Carrascosa E, Bull JN, Martínez-Núñez E, Scholz MS, Buntine JT, Bieske EJ. Photoisomerization of Linear and Stacked Isomers of a Charged Styryl Dye: A Tandem Ion Mobility Study. J Am Soc Mass Spectrom 2021; 32:2842-2851. [PMID: 34787413 PMCID: PMC8640989 DOI: 10.1021/jasms.1c00264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/21/2021] [Accepted: 11/01/2021] [Indexed: 06/13/2023]
Abstract
The photoisomerization behavior of styryl 9M, a common dye used in material sciences, is investigated using tandem ion mobility spectrometry (IMS) coupled with laser spectroscopy. Styryl 9M has two alkene linkages, potentially allowing for four geometric isomers. IMS measurements demonstrate that at least three geometric isomers are generated using electrospray ionization with the most abundant forms assigned to a combination of EE (major) and ZE (minor) geometric isomers, which are difficult to distinguish using IMS as they have similar collision cross sections. Two additional but minor isomers are generated by collisional excitation of the electrosprayed styryl 9M ions and are assigned to the EZ and ZZ geometric isomers, with the latter predicted to have a π-stacked configuration. The isomer assignments are supported through calculations of equilibrium structures, collision cross sections, and statistical isomerization rates. Photoexcitation of selected isomers using an IMS-photo-IMS strategy shows that each geometric isomer photoisomerizes following absorption of near-infrared and visible light, with the EE isomer possessing a S1 ← S0 electronic transition with a band maximum near 680 nm and shorter wavelength S2 ← S0 electronic transition with a band maximum near 430 nm. The study demonstrates the utility of the IMS-photo-IMS strategy for providing fundamental gas-phase photochemical information on molecular systems with multiple isomerizable bonds.
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Affiliation(s)
- Eduardo Carrascosa
- School
of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - James N. Bull
- School
of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
- School
of Chemistry, Norwich Research Park, University
of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Emilio Martínez-Núñez
- Departamento
de Química Física, Universidade
de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Michael S. Scholz
- School
of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Jack T. Buntine
- School
of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Evan J. Bieske
- School
of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
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21
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Coughlan NJA, Stockett MH, Kjær C, Ashworth EK, Bulman Page PC, Meech SR, Brøndsted Nielsen S, Blancafort L, Hopkins WS, Bull JN. Action spectroscopy of the isolated red Kaede fluorescent protein chromophore. J Chem Phys 2021; 155:124304. [PMID: 34598549 DOI: 10.1063/5.0063258] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Incorporation of fluorescent proteins into biochemical systems has revolutionized the field of bioimaging. In a bottom-up approach, understanding the photophysics of fluorescent proteins requires detailed investigations of the light-absorbing chromophore, which can be achieved by studying the chromophore in isolation. This paper reports a photodissociation action spectroscopy study on the deprotonated anion of the red Kaede fluorescent protein chromophore, demonstrating that at least three isomers-assigned to deprotomers-are generated in the gas phase. Deprotomer-selected action spectra are recorded over the S1 ← S0 band using an instrument with differential mobility spectrometry coupled with photodissociation spectroscopy. The spectrum for the principal phenoxide deprotomer spans the 480-660 nm range with a maximum response at ≈610 nm. The imidazolate deprotomer has a blue-shifted action spectrum with a maximum response at ≈545 nm. The action spectra are consistent with excited state coupled-cluster calculations of excitation wavelengths for the deprotomers. A third gas-phase species with a distinct action spectrum is tentatively assigned to an imidazole tautomer of the principal phenoxide deprotomer. This study highlights the need for isomer-selective methods when studying the photophysics of biochromophores possessing several deprotonation sites.
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Affiliation(s)
- Neville J A Coughlan
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Mark H Stockett
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Christina Kjær
- Department of Physics and Astronomy, Aarhus University, Aarhus 8000, Denmark
| | - Eleanor K Ashworth
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Philip C Bulman Page
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Stephen R Meech
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | | | - Lluís Blancafort
- Institut de Química Computacional i Catálisi and Departament de Química, Universitat de Girona, C/M.A. Capmany 69, 17003 Girona, Spain
| | - W Scott Hopkins
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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22
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Giacomozzi L, Kjær C, Brøndsted Nielsen S, Ashworth EK, Bull JN, Stockett MH. Non-statistical fragmentation in photo-activated flavin mononucleotide anions. J Chem Phys 2021; 155:044305. [PMID: 34340366 DOI: 10.1063/5.0056415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The spectroscopy and photo-induced dissociation of flavin mononucleotide anions in vacuo are investigated over the 300-500 nm wavelength range. Comparison of the dependence of fragment ion yields as a function of deposited photon energy with calculated dissociation energies and collision-induced dissociation measurements performed under single-collision conditions suggests that a substantial fraction of photo-activated ions decompose through non-statistical fragmentation pathways. Among these pathways is the dominant photo-induced fragmentation channel, the loss of a fragment identified as formylmethylflavin. The fragment ion specific action spectra reveal electronic transition energies close to those for flavins in solution and previously published gas-phase measurements, although the photo-fragment yield upon excitation of the S2 ← S0 transition appears to be suppressed.
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Affiliation(s)
| | - Christina Kjær
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | | | - Eleanor K Ashworth
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - James N Bull
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Mark H Stockett
- Department of Physics, Stockholm University, Stockholm, Sweden
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23
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Ashworth EK, Anstöter CS, Verlet JRR, Bull JN. Autodetachment dynamics of 2-naphthoxide and implications for astrophysical anion abundance. Phys Chem Chem Phys 2021; 23:5817-5823. [PMID: 33686387 DOI: 10.1039/d1cp00261a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Astrochemical modelling has proposed that 10% or more of interstellar carbon could be tied up as polycyclic aromatic hydrocarbon (PAH) molecules. Developing reliable models of the interstellar carbon lifecycle requires calibration data obtained through laboratory studies on relevant chemical and physical processes, including on the photo-induced and electron-induced dynamics of potential interstellar PAHs. Here, the excited state dynamics of the S1(ππ*) state of 2-naphthoxide are investigated using frequency-, angle-, and time-resolved photoelectron imaging. Frequency-resolved photoelectron spectra taken over the S1(ππ*) band reveal low electron kinetic energy structure consistent with an indirect, vibrational mode-specific electron detachment mechanism. Time-resolved photoelectron imaging using a pump photon energy tuned to the 0-0 transition of the S1(ππ*) band (hν = 2.70 eV) and a non-resonant probe photon provides the excited state autodetachment lifetime at τ = 130 ± 10 fs. There is no evidence for internal conversion to the ground electronic state or a dipole-bound state. These results imply that 2-naphthoxide has no resilience to photodestruction through the absorption of visible radiation resonant with the S1(ππ*) band, and that electron capture by the S1(ππ*) state, which is formally a shape resonance, is not a doorway state to a stable interstellar anion.
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Affiliation(s)
- Eleanor K Ashworth
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Cate S Anstöter
- Department of Chemistry, Durham University, Durham, DH1 3LE, UK.
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham, DH1 3LE, UK.
| | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
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24
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Stockett MH, Bull JN, Buntine JT, Carrascosa E, Ji M, Kono N, Schmidt HT, Zettergren H. Unimolecular fragmentation and radiative cooling of isolated PAH ions: A quantitative study. J Chem Phys 2020; 153:154303. [PMID: 33092387 DOI: 10.1063/5.0027773] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Time-resolved spontaneous and laser-induced unimolecular fragmentation of perylene cations (C20H12 +) has been measured on timescales up to 2 s in a cryogenic electrostatic ion beam storage ring. We elaborate a quantitative model, which includes fragmentation in competition with radiative cooling via both vibrational and electronic (recurrent fluorescence) de-excitation. Excellent agreement with experimental results is found when sequential fragmentation of daughter ions co-stored with the parent perylene ions is included in the model. Based on the comparison of the model to experiment, we constrain the oscillator strength of the D1 → D0 emissive electronic transition in perylene (fRF = 0.055 ± 0.011), as well as the absolute absorption cross section of the D5 ← D0 excitation transition (σabs > 670 Mb). The former transition is responsible for the laser-induced and recurrent fluorescence of perylene, and the latter is the most prominent in the absorption spectrum. The vibrational cooling rate is found to be consistent with the simple harmonic cascade approximation. Quantitative experimental benchmarks of unimolecular processes in polycyclic aromatic hydrocarbon ions like perylene are important for refining astrochemical models.
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Affiliation(s)
- Mark H Stockett
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - James N Bull
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Jack T Buntine
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | - Eduardo Carrascosa
- Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne, EPFL SB ISIC LCPM, Station 6, CH-1015 Lausanne, Switzerland
| | - MingChao Ji
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Naoko Kono
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Henning T Schmidt
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
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25
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Abstract
Dye molecules based on the xanthene moiety are widely used as fluorescent probes in bioimaging and technological applications due to their large absorption cross-section for visible light and high fluorescence quantum yield. These applications require a clear understanding of the dye's inherent photophysics and the effect of a condensed-phase environment. Here, the gas-phase photophysics of the rose bengal doubly deprotonated dianion [RB - 2H]2-, deprotonated monoanion [RB - H]-, and doubly deprotonated radical anion [RB - 2H]•- is investigated using photodetachment, photoelectron, and dispersed fluorescence action spectroscopies, and tandem ion mobility spectrometry (IMS) coupled with laser excitation. For [RB - 2H]2-, photodetachment action spectroscopy reveals a clear band in the visible (450-580 nm) with vibronic structure. Electron affinity and repulsive Coulomb barrier (RCB) properties of the dianion are characterized using frequency-resolved photoelectron spectroscopy, revealing a decreased RCB compared with that of fluorescein dianions due to electron delocalization over halogen atoms. Monoanions [RB - H]- and [RB - 2H]•- differ in nominal mass by 1 Da but are difficult to study individually using action spectroscopies that isolate target ions using low-resolution mass spectrometry. This work shows that the two monoanions are readily distinguished and probed using the IMS-photo-IMS and photo-IMS-photo-IMS strategies, providing distinct but overlapping photodissociation action spectra in the visible spectral range. Gas-phase fluorescence was not detected from photoexcited [RB - 2H]2- due to rapid electron ejection. However, both [RB - H]- and [RB - 2H]•- show a weak fluorescence signal. The [RB - H]- action spectra show a large Stokes shift of ∼1700 cm-1, while the [RB - 2H]•- action spectra show no appreciable Stokes shift. This difference is explained by considering geometries of the ground and fluorescing states.
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Affiliation(s)
- Mark H Stockett
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Christina Kjær
- Department of Physics and Astronomy, Aarhus University, Aarhus 8000, Denmark
| | - Steven Daly
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumiére Matiére UMR 5306, F-69100 Villeurbanne, France
| | - Evan J Bieske
- School of Chemistry, University of Melbourne, Parkville VIC 3010, Australia
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | | | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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Gregory J, Verlet JRR, Bull JN. Spectroscopic characterisation of radical polyinterhalogen molecules. Phys Chem Chem Phys 2020; 22:8284-8288. [PMID: 32270847 DOI: 10.1039/d0cp01311k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spectroscopic characterisations of the radical polyinterhalogen molecules IF2 and I2F are reported using anion photoelectron spectroscopy. The corresponding parent anions, IF2- and I2F-, are common products formed in hard Ar-CF3I plasmas and are relevant in the semiconductor manufacture industry. The I2F- species, which is present as the [I-I-F]- isomer, is a "non-classical" polyinterhalogen.
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Affiliation(s)
- Joe Gregory
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Jan R R Verlet
- Department of Chemistry, Durham University, South Road, Durham DH1 3LE, UK
| | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
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27
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Abstract
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Nonvalence states
of neutral molecules (Rydberg states) play important
roles in nonadiabatic dynamics of excited states. In anions, such
nonadiabatic transitions between nonvalence and valence states have
been much less explored even though they are believed to play important
roles in electron capture and excited state dynamics of anions. The
aim of this Feature Article is to provide an overview of recent experimental
observations, based on time-resolved photoelectron imaging, of valence
to nonvalence and nonvalence to valence transitions in anions and
to demonstrate that such dynamics may be commonplace in the excited
state dynamics of molecular anions and cluster anions.
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Affiliation(s)
- Jan R R Verlet
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Cate S Anstöter
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Joshua P Rogers
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
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28
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Carrascosa E, Petermayer C, Scholz MS, Bull JN, Dube H, Bieske EJ. Reversible Photoswitching of Isolated Ionic Hemiindigos with Visible Light. Chemphyschem 2020; 21:680-685. [PMID: 31736199 PMCID: PMC7277040 DOI: 10.1002/cphc.201900963] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Indexed: 01/06/2023]
Abstract
Indigoid chromophores have emerged as versatile molecular photoswitches, offering efficient reversible photoisomerization upon exposure to visible light. Here we report synthesis of a new class of permanently charged hemiindigos (HIs) and characterization of photochemical properties in gas phase and solution. Gas-phase studies, which involve exposing mobility-selected ions in a tandem ion mobility mass spectrometer to tunable wavelength laser radiation, demonstrate that the isolated HI ions are photochromic and can be reversibly photoswitched between Z and E isomers. The Z and E isomers have distinct photoisomerization response spectra with maxima separated by 40-80 nm, consistent with theoretical predictions for their absorption spectra. Solvation of the HI molecules in acetonitrile displaces the absorption bands to lower energy. Together, gas-phase action spectroscopy and solution NMR and UV/Vis absorption spectroscopy represent a powerful approach for studying the intrinsic photochemical properties of HI molecular switches.
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Affiliation(s)
- Eduardo Carrascosa
- School of ChemistryThe University of Melbourne3010Parkville (VIC)Australia
| | - Christian Petermayer
- Department für Chemie and Munich Center for Integrated Protein Science CIPSMLudwig-Maximilians-Universität München81377MunichGermany
| | - Michael S. Scholz
- School of ChemistryThe University of Melbourne3010Parkville (VIC)Australia
| | - James N. Bull
- School of ChemistryThe University of Melbourne3010Parkville (VIC)Australia
- School of Chemistry, Norwich Research ParkUniversity of East AngliaNorwichNR4 7TJUnited Kingdom
| | - Henry Dube
- Department für Chemie and Munich Center for Integrated Protein Science CIPSMLudwig-Maximilians-Universität München81377MunichGermany
| | - Evan J. Bieske
- School of ChemistryThe University of Melbourne3010Parkville (VIC)Australia
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29
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Bull JN, Anstöter CS, Verlet JRR. Fingerprinting the Excited-State Dynamics in Methyl Ester and Methyl Ether Anions of Deprotonated para-Coumaric Acid. J Phys Chem A 2020; 124:2140-2151. [PMID: 32105474 DOI: 10.1021/acs.jpca.9b11993] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Chromophores based on the para-hydroxycinnamate moiety are widespread in the natural world, including as the photoswitching unit in photoactive yellow protein and as a sunscreen in the leaves of plants. Here, photodetachment action spectroscopy combined with frequency- and angle-resolved photoelectron imaging is used to fingerprint the excited-state dynamics over the first three bright action-absorption bands in the methyl ester anions (pCEs-) of deprotonated para-coumaric acid at a temperature of ∼300 K. The excited states associated with the action-absorption bands are classified as resonances because they are situated in the detachment continuum and are open to autodetachment. The frequency-resolved photoelectron spectrum for pCEs- indicates that all photon energies over the S1(ππ*) band lead to similar vibrational autodetachment dynamics. The S2(nπ*) band is Herzberg-Teller active and has comparable brightness to the higher lying 21(ππ*) band. The frequency-resolved photoelectron spectrum over the S2(nπ*) band indicates more efficient internal conversion to the S1(ππ*) state for photon energies resonant with the Franck-Condon modes (∼80%) compared with the Herzberg-Teller modes (∼60%). The third action-absorption band, which corresponds to excitation of the 21(ππ*) state, shows complex and photon energy-dependent dynamics, with 20-40% of photoexcited population internally converting to the S1(ππ*) state. There is also evidence for a mode-specific competition between prompt autodetachment and internal conversion on the red edge of the 21(ππ*) band. There is no evidence for recovery of the ground electronic state and statistical electron ejection (thermionic emission) following photoexcitation over any of the three action-absorption bands. The photoelectron spectra for the deprotonated methyl ether derivative (pCEt-) at photon energies over the S1(ππ*) and S2(nπ*) bands indicate diametrically opposed dynamics compared with pCEs-, namely, intense thermionic emission due to efficient recovery of the ground electronic state.
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Affiliation(s)
- James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, U.K
| | - Cate S Anstöter
- Department of Chemistry, Durham University, Durham DH1 3LE, U.K
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham DH1 3LE, U.K
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30
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Carrascosa E, Bull JN, Buntine JT, da Silva G, Santos PF, Bieske EJ. Near-infrared reversible photoswitching of an isolated azobenzene-stilbene dye. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2019.137065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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31
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Bull JN, Anstöter CS, Verlet JRR. Ultrafast valence to non-valence excited state dynamics in a common anionic chromophore. Nat Commun 2019; 10:5820. [PMID: 31862884 PMCID: PMC6925192 DOI: 10.1038/s41467-019-13819-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 11/27/2019] [Indexed: 12/19/2022] Open
Abstract
Non-valence states in neutral molecules (Rydberg states) have well-established roles and importance in photochemistry, however, considerably less is known about the role of non-valence states in photo-induced processes in anions. Here, femtosecond time-resolved photoelectron imaging is used to show that photoexcitation of the S1(ππ*) state of the methyl ester of deprotonated para-coumaric acid – a model chromophore for photoactive yellow protein (PYP) – leads to a bifurcation of the excited state wavepacket. One part remains on the S1(ππ*) state forming a twisted intermediate, whilst a second part leads to the formation of a non-valence (dipole-bound) state. Both populations eventually decay independently by vibrational autodetachment. Valence-to-non-valence internal conversion has hitherto not been observed in the intramolecular photophysics of an isolated anion, raising questions into how common such processes might be, given that many anionic chromophores have bright valence states near the detachment threshold. Photoactive biomolecules rely on chromophores whose photochemistry depends on the environment. Here, the excited state dynamics of a model for the anionic biochromophore in photoactive yellow protein is investigated by time-resolved photoelectron spectroscopy showing involvement of a non-valence state, and lack of E-Z isomerisation in the gas phase.
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Affiliation(s)
- James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Cate S Anstöter
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK
| | - Jan R R Verlet
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK.
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32
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Bull JN, Scholz MS, Carrascosa E, Kristiansson MK, Eklund G, Punnakayathil N, de Ruette N, Zettergren H, Schmidt HT, Cederquist H, Stockett MH. Ultraslow radiative cooling of Cn− (n = 3–5). J Chem Phys 2019; 151:114304. [DOI: 10.1063/1.5114678] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- James N. Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Michael S. Scholz
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | - Eduardo Carrascosa
- Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne, EPFL SB ISIC LCPM, Station 6, CH-1015 Lausanne, Switzerland
| | | | - Gustav Eklund
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | | | | | | | | | - Henrik Cederquist
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Mark H. Stockett
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
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33
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Bull JN, West CW, Anstöter CS, da Silva G, Bieske EJ, Verlet JRR. Ultrafast photoisomerisation of an isolated retinoid. Phys Chem Chem Phys 2019; 21:10567-10579. [PMID: 31073587 DOI: 10.1039/c9cp01624d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The photoinduced excited state dynamics of gas-phase trans-retinoate (deprotonated trans-retinoic acid, trans-RA-) are studied using tandem ion mobility spectrometry coupled with laser spectroscopy, and frequency-, angle- and time-resolved photoelectron imaging. Photoexcitation of the bright S3(ππ*) ← S0 transition leads to internal conversion to the S1(ππ*) state on a ≈80 fs timescale followed by recovery of S0 and concomitant isomerisation to give the 13-cis (major) and 9-cis (minor) photoisomers on a ≈180 fs timescale. The sub-200 fs stereoselective photoisomerisation parallels that for the retinal protonated Schiff base chromophore in bacteriorhodopsin. Measurements on trans-RA- in methanol using the solution photoisomerisation action spectroscopy technique show that 13-cis-RA- is also the principal photoisomer, although the 13-cis and 9-cis photoisomers are formed with an inverted branching ratio with photon energy in methanol when compared with the gas phase, presumably due to solvent-induced modification of potential energy surfaces and inhibition of electron detachment processes. Comparison of the gas-phase time-resolved data with transient absorption spectroscopy measurements on retinoic acid in methanol suggest that photoisomerisation is roughly six times slower in solution. This work provides clear evidence that solvation significantly affects the photoisomerisation dynamics of retinoid molecules.
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Affiliation(s)
- James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Christopher W West
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Cate S Anstöter
- Department of Chemistry, Durham University, Durham DH1 3LE, UK
| | - Gabriel da Silva
- Department of Chemical Engineering, University of Melbourne, Parkville, VIC 3010, Australia
| | - Evan J Bieske
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham DH1 3LE, UK
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34
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Bull JN, Silva GD, Scholz MS, Carrascosa E, Bieske EJ. Photoinitiated Intramolecular Proton Transfer in Deprotonated para-Coumaric Acid. J Phys Chem A 2019; 123:4419-4430. [DOI: 10.1021/acs.jpca.9b02023] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- James N. Bull
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Gabriel da Silva
- Department of Chemical Engineering, University of Melbourne, Parkville, VIC 3010, Australia
| | - Michael S. Scholz
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | - Eduardo Carrascosa
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | - Evan J. Bieske
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
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35
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Rogers JP, Anstöter CS, Bull JN, Curchod BFE, Verlet JRR. Photoelectron Spectroscopy of the Hexafluorobenzene Cluster Anions: (C 6F 6) n- ( n = 1-5) and I -(C 6F 6). J Phys Chem A 2019; 123:1602-1612. [PMID: 30694676 DOI: 10.1021/acs.jpca.8b11627] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Frequency-resolved (2D) photoelectron (PE) spectra of the anionic clusters (C6F6) n-, for n = 1-5, and time-resolved PE spectra of I-C6F6 are presented using a newly built instrument and supported by electronic structure calculations. From the 2D PE spectra, the vertical detachment energy (VDE) of C6F6- was measured to be 1.60 ± 0.01 eV, and the adiabatic detachment energy (ADE) was ≤0.70 eV. The PE spectra also contain fingerprints of resonance dynamics over certain photon energy ranges, in agreement with the calculations. An action spectrum over the lowest resonance is also presented. The 2D spectra of (C6F6) n- show that the cluster can be described as C6F6-(C6F6) n-1. The VDE increases linearly (200 ± 20 meV n-1) due to the stabilizing influence on the anion of the solvating C6F6 molecules. For I-C6F6, action spectra of the absorption just below both detachment channels are presented. Time-resolved PE spectra of I-C6F6 excited at 3.10 eV and probed at 1.55 eV reveal a short-lived nonvalence state of C6F6- that coherently evolves into the valence ground state of the anion and induces vibrational motion along a specific buckling coordinate. Electronic structure calculations along the displacement of this mode show that at the extreme buckling angle the probe can access an excited state of the anion that is bound at that geometry but adiabatically unbound. Hence, slow electrons are emitted and show dynamics that predominantly probe the outer-turning point of the motion. A PE spectrum taken at t = 0 contains a vibrational structure assigned to a specific Raman- or IR-active mode of C6F6.
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Affiliation(s)
- Joshua P Rogers
- Department of Chemistry , Durham University , Durham DH1 3LE , United Kingdom
| | - Cate S Anstöter
- Department of Chemistry , Durham University , Durham DH1 3LE , United Kingdom
| | - James N Bull
- Department of Chemistry , Durham University , Durham DH1 3LE , United Kingdom
| | - Basile F E Curchod
- Department of Chemistry , Durham University , Durham DH1 3LE , United Kingdom
| | - Jan R R Verlet
- Department of Chemistry , Durham University , Durham DH1 3LE , United Kingdom
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36
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Bull JN, Buntine JT, Scholz MS, Carrascosa E, Giacomozzi L, Stockett MH, Bieske EJ. Photodetachment and photoreactions of substituted naphthalene anions in a tandem ion mobility spectrometer. Faraday Discuss 2019; 217:34-46. [DOI: 10.1039/c8fd00217g] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Tandem IMS-laser-IMS is used to probe the intrinsic electronic absorptions of deprotonated substituted naphthalene anions.
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37
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Bull JN, Carrascosa E, Giacomozzi L, Bieske EJ, Stockett MH. Ion mobility action spectroscopy of flavin dianions reveals deprotomer-dependent photochemistry. Phys Chem Chem Phys 2018; 20:19672-19681. [PMID: 30014081 PMCID: PMC6063075 DOI: 10.1039/c8cp03244k] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Photo-induced proton transfer, deprotomer-dependent photochemistry, and intramolecular charge transfer in flavin anions are investigated using action spectroscopy.
The intrinsic optical properties and photochemistry of flavin adenine dinucleotide (FAD) dianions are investigated using a combination of tandem ion mobility spectrometry and action spectroscopy. Two principal isomers are observed, the more stable form being deprotonated on the isoalloxazine group and a phosphate (N-3,PO4 deprotomer), and the other on the two phosphates (PO4,PO4 deprotomer). Ion mobility data and electronic action spectra suggest that photo-induced proton transfer occurs from the isoalloxazine group to a phosphate group, converting the PO4,PO4 deprotomer to the N-3,PO4 deprotomer. Comparisons of the isomer selective action spectra of FAD dianions and flavin monoanions with solution spectra and gas-phase photodissociation action spectra suggests that solvation shifts the electronic absorption of the deprotonated isoalloxazine group to higher energy. This is interpreted as evidence for significant charge transfer in the lowest optical transition of deprotonated isoalloxazine. Overall, this work demonstrates that the site of deprotonation of flavin anions strongly affects their electronic absorptions and photochemistry.
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Affiliation(s)
- James N Bull
- School of Chemistry, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Eduardo Carrascosa
- School of Chemistry, University of Melbourne, Melbourne, VIC 3010, Australia
| | | | - Evan J Bieske
- School of Chemistry, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Mark H Stockett
- School of Chemistry, University of Melbourne, Melbourne, VIC 3010, Australia and Department of Physics, Stockholm University, Stockholm, Sweden.
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38
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Bull JN, Scholz MS, Carrascosa E, da Silva G, Bieske EJ. Double Molecular Photoswitch Driven by Light and Collisions. Phys Rev Lett 2018; 120:223002. [PMID: 29906145 DOI: 10.1103/physrevlett.120.223002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Indexed: 06/08/2023]
Abstract
The shapes of many molecules can be transformed by light or heat. Here we investigate collision- and photon-induced interconversions of EE, EZ, and ZZ isomers of the isolated Congo red (CR) dianion, a double molecular switch containing two ─N═N─ azo groups, each of which can have the E or Z configuration. We find that collisional activation of CR dianions drives a one-way ZZ→EZ→EE cascade towards the lowest-energy isomer, whereas the absorption of a single photon over the 270-600 nm range can switch either azo group from E to Z or Z to E, driving the CR dianion to lower- or higher-energy forms. The experimental results, which are interpreted with the aid of calculated statistical isomerization rates, indicate that photoisomerization of CR in the gas phase involves a passage through conical intersection seams linking the excited and ground state potential energy surfaces rather than through isomerization on the ground state potential energy surface following internal conversion.
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Affiliation(s)
- James N Bull
- School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Michael S Scholz
- School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Eduardo Carrascosa
- School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Gabriel da Silva
- Department of Chemical Engineering, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Evan J Bieske
- School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
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39
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Carrascosa E, Bull JN, Scholz MS, Coughlan NJA, Olsen S, Wille U, Bieske EJ. Reversible Photoisomerization of the Isolated Green Fluorescent Protein Chromophore. J Phys Chem Lett 2018; 9:2647-2651. [PMID: 29724104 DOI: 10.1021/acs.jpclett.8b01201] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Fluorescent proteins have revolutionized the visualization of biological processes, prompting efforts to understand and control their intrinsic photophysics. Here we investigate the photoisomerization of deprotonated p-hydroxybenzylidene-2,3-dimethylimidazolinone anion (HBDI-), the chromophore in green fluorescent protein and in Dronpa protein, where it plays a role in switching between fluorescent and nonfluorescent states. In the present work, isolated HBDI- molecules are switched between the Z and E forms in the gas phase in a tandem ion mobility mass spectrometer outfitted for selecting the initial and final isomers. Excitation of the S1 ← S0 transition provokes both Z → E and E → Z photoisomerization, with a maximum response for both processes at 480 nm. Photodetachment is a minor channel at low light intensity. At higher light intensities, absorption of several photons in the drift region drives photofragmentation, through channels involving CH3 loss and concerted CO and CH3CN loss, although isomerization remains the dominant process.
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Affiliation(s)
- Eduardo Carrascosa
- School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia
| | - James N Bull
- School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Michael S Scholz
- School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Neville J A Coughlan
- School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Seth Olsen
- School of Chemistry , Monash University , Clayton , Victoria 3800 , Australia
| | - Uta Wille
- School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Evan J Bieske
- School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia
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40
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Scholz MS, Bull JN, Carrascosa E, Adamson BD, Kosgei GK, Rack JJ, Bieske EJ. Linkage Photoisomerization of an Isolated Ruthenium Sulfoxide Complex: Sequential versus Concerted Rearrangement. Inorg Chem 2018; 57:5701-5706. [PMID: 29663799 DOI: 10.1021/acs.inorgchem.8b00871] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ruthenium sulfoxide complexes undergo thermally reversible linkage isomerization of sulfoxide ligands from S- to O-bound in response to light. Here, we report photoisomerization action spectra for a ruthenium bis-sulfoxide molecular photoswitch, [Ru(bpy)2(bpSO)]2+, providing the first direct evidence for photoisomerization of a transition metal complex in the gas phase. The linkage isomers are separated and isolated in a tandem drift tube ion mobility spectrometer and exposed to tunable laser radiation provoking photoisomerization. Direct switching of the S,S-isomer to the O,O-isomer following absorption of a single photon is the predominant isomerization pathway in the gas phase, unlike in solution, where stepwise isomerization is observed with each sulfoxide ligand switching in turn. The change in isomerization dynamics is attributed to rapid vibrational quenching that suppresses isomerization in solution. Supporting electronic structure calculations predict the wavelengths and intensities of the peaks in the photoisomerization action spectra of the S,S- and S,O-isomers, indicating that they correspond to metal-to-ligand charge transfer (MLCT) and ligand-centered ππ* transitions.
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Affiliation(s)
- Michael S Scholz
- School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | - James N Bull
- School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Eduardo Carrascosa
- School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Brian D Adamson
- School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia.,Sandia National Laboratories, Livermore , California 94550 , United States
| | - Gilbert K Kosgei
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Jeffrey J Rack
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Evan J Bieske
- School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
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41
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Poad BLJ, Maccarone AT, Yu H, Mitchell TW, Saied EM, Arenz C, Hornemann T, Bull JN, Bieske EJ, Blanksby SJ. Differential-Mobility Spectrometry of 1-Deoxysphingosine Isomers: New Insights into the Gas Phase Structures of Ionized Lipids. Anal Chem 2018; 90:5343-5351. [PMID: 29608293 DOI: 10.1021/acs.analchem.8b00469] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Separation and structural identification of lipids remain a major challenge for contemporary lipidomics. Regioisomeric lipids differing only in position(s) of unsaturation are often not differentiated by conventional liquid chromatography-mass spectrometry approaches leading to the incomplete, or sometimes incorrect, assignation of molecular structure. Here we describe an investigation of the gas phase separations by differential-mobility spectrometry (DMS) of a series of synthetic analogues of the recently described 1-deoxysphingosine. The dependence of the DMS behavior on the position of the carbon-carbon double bond within the ionized lipid is systematically explored and compared to trends from complementary investigations, including collision cross-sections measured by drift tube ion mobility, reaction efficiency with ozone, and molecular dynamics simulations. Consistent trends across these modes of interrogation point to the importance of direct, through-space interactions between the charge site and the carbon-carbon double bond. Differences in the geometry and energetics of this intramolecular interaction underpin DMS separations and influence reactivity trends between regioisomers. Importantly, the disruption and reformation of these intramolecular solvation interactions during DMS are proposed to be the causative factor in the observed separations of ionized lipids which are shown to have otherwise identical collision cross-sections. These findings provide key insights into the strengths and limitations of current ion-mobility technologies for lipid isomer separations and can thus guide a more systematic approach to improved analytical separations in lipidomics.
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Affiliation(s)
- Berwyck L J Poad
- Central Analytical Research Facility, Institute for Future Environments , Queensland University of Technology , Brisbane , Queensland 4001 , Australia
| | - Alan T Maccarone
- Mass Spectrometry User Resource and Research Facility , University of Wollongong , Wollongong , New South Wales 2522 , Australia.,School of Chemistry , University of Wollongong , Wollongong , New South Wales 2522 , Australia
| | - Haibo Yu
- School of Chemistry , University of Wollongong , Wollongong , New South Wales 2522 , Australia
| | - Todd W Mitchell
- School of Medicine , University of Wollongong , Wollongong , New South Wales 2522 , Australia
| | - Essa M Saied
- Institute for Chemistry , Humboldt Universität zu Berlin , 12489 Berlin , Germany.,Chemistry Department, Faculty of Science , Suez Canal University , 41522 Ismailia , Egypt
| | - Christoph Arenz
- Institute for Chemistry , Humboldt Universität zu Berlin , 12489 Berlin , Germany
| | - Thorsten Hornemann
- Institute of Clinical Chemistry , University Hospital of Zurich , CH-8091 Zurich , Switzerland
| | - James N Bull
- School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Evan J Bieske
- School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments , Queensland University of Technology , Brisbane , Queensland 4001 , Australia
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42
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Abstract
Donor-acceptor Stenhouse adducts (DASAs) are a new class of photoswitching molecules with excellent fatigue resistance and synthetic tunability. Here, tandem ion mobility mass spectrometry coupled with laser excitation is used to characterize the photocyclization reaction of isolated, charge-tagged DASA molecules over the 450-580 nm range. The experimental maximum response at 530 nm agrees with multireference perturbation theory calculations for the S1 ← S0 transition maximum at 533 nm. Photocyclization in the gas phase involves absorption of at least two photons; the first photon induces Z-E isomerization from the linear isomer to metastable intermediate isomers, while the second photon drives another E-Z isomerization and 4π-electrocyclization reaction. Cyclization is thermally reversible in the gas phase with collisional excitation.
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Affiliation(s)
- James N Bull
- School of Chemistry, University of Melbourne , Parkville, Victoria 3010, Australia
| | - Eduardo Carrascosa
- School of Chemistry, University of Melbourne , Parkville, Victoria 3010, Australia
| | - Neil Mallo
- School of Chemistry, UNSW Sydney , High Street, Kensington, New South Wales 2052, Australia
| | - Michael S Scholz
- School of Chemistry, University of Melbourne , Parkville, Victoria 3010, Australia
| | - Gabriel da Silva
- Department of Chemical Engineering, University of Melbourne , Parkville, Victoria 3010, Australia
| | - Jonathon E Beves
- School of Chemistry, UNSW Sydney , High Street, Kensington, New South Wales 2052, Australia
| | - Evan J Bieske
- School of Chemistry, University of Melbourne , Parkville, Victoria 3010, Australia
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43
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Bull JN, Scholz MS, Carrascosa E, Bieske EJ. FromEtoZand back again: reversible photoisomerisation of an isolated charge-tagged azobenzene. Phys Chem Chem Phys 2018; 20:509-513. [DOI: 10.1039/c7cp07278c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Substituted azobenzenes serve as chromophores and actuators in a wide range of molecular photoswitches.
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Affiliation(s)
- James N. Bull
- School of Chemistry
- University of Melbourne
- Parkville
- Australia
| | | | | | - Evan J. Bieske
- School of Chemistry
- University of Melbourne
- Parkville
- Australia
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44
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Scholz MS, Bull JN, Coughlan NJA, Carrascosa E, Adamson BD, Bieske EJ. Photoisomerization of Protonated Azobenzenes in the Gas Phase. J Phys Chem A 2017; 121:6413-6419. [DOI: 10.1021/acs.jpca.7b05902] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
| | - James N. Bull
- School
of Chemistry, University of Melbourne, Melbourne, Australia
| | - Neville J. A. Coughlan
- School
of Chemistry, University of Melbourne, Melbourne, Australia
- Department
of Chemistry, University of Oxford, Oxford, United Kingdom
| | | | - Brian D. Adamson
- School
of Chemistry, University of Melbourne, Melbourne, Australia
- Sandia National Laboratories, Livermore, California 94551, United States
| | - Evan J. Bieske
- School
of Chemistry, University of Melbourne, Melbourne, Australia
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45
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Affiliation(s)
- James N. Bull
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | | | - Evan J. Bieske
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
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46
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Georgiou DC, Haghighatbin MA, Hogan CF, Scholz MS, Bull JN, Bieske EJ, Wilson DJD, Dutton JL. A Strong
cis
‐Effect in an Imidazole‐Imidazolium‐Substituted Alkene. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201702287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Dayne C. Georgiou
- Department of Chemistry and Physics La Trobe Institute for Molecular Science La Trobe University Melbourne Victoria 3086 Australia
| | - Mohammad A. Haghighatbin
- Department of Chemistry and Physics La Trobe Institute for Molecular Science La Trobe University Melbourne Victoria 3086 Australia
| | - Conor F. Hogan
- Department of Chemistry and Physics La Trobe Institute for Molecular Science La Trobe University Melbourne Victoria 3086 Australia
| | - Michael S. Scholz
- School of Chemistry University of Melbourne Parkville Victoria 3010 Australia
| | - James N. Bull
- School of Chemistry University of Melbourne Parkville Victoria 3010 Australia
| | - Evan J. Bieske
- School of Chemistry University of Melbourne Parkville Victoria 3010 Australia
| | - David J. D. Wilson
- Department of Chemistry and Physics La Trobe Institute for Molecular Science La Trobe University Melbourne Victoria 3086 Australia
| | - Jason L. Dutton
- Department of Chemistry and Physics La Trobe Institute for Molecular Science La Trobe University Melbourne Victoria 3086 Australia
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47
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Bull JN, Verlet JRR. Observation and ultrafast dynamics of a nonvalence correlation-bound state of an anion. Sci Adv 2017; 3:e1603106. [PMID: 28560345 PMCID: PMC5438219 DOI: 10.1126/sciadv.1603106] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/22/2017] [Indexed: 06/07/2023]
Abstract
Nonvalence states of molecular anions play key roles in processes, such as electron mobility, in rare-gas liquids, radiation-induced damage to DNA, and the formation of anions in the interstellar medium. Recently, a class of nonvalence bound anion state has been predicted by theory in which correlation forces are predominantly responsible for binding the excess electron. We present a direct spectroscopic observation of this nonvalence correlation-bound state (CBS) in the para-toluquinone trimer cluster anion. Time-resolved photoelectron velocity map imaging shows that photodetachment of the CBS produces a narrow and highly anisotropic photoelectron distribution, consistent with detachment from an s-like orbital. The CBS is bound by ~50 meV and decays by vibration-mediated autodetachment with a lifetime of 700 ± 100 fs. These states are likely to be common in large and/or polarizable anions and clusters and may act as doorway states in electron attachment processes.
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Affiliation(s)
- James N Bull
- Department of Chemistry, University of Durham, Durham DH1 3LE, U.K
- School of Chemistry, University of Melbourne, Parkville, Melbourne, Victoria 3010, Australia
| | - Jan R R Verlet
- Department of Chemistry, University of Durham, Durham DH1 3LE, U.K
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48
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Georgiou DC, Haghighatbin MA, Hogan CF, Scholz MS, Bull JN, Bieske EJ, Wilson DJD, Dutton JL. A Strong
cis
‐Effect in an Imidazole‐Imidazolium‐Substituted Alkene. Angew Chem Int Ed Engl 2017; 56:8473-8480. [DOI: 10.1002/anie.201702287] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Indexed: 01/02/2023]
Affiliation(s)
- Dayne C. Georgiou
- Department of Chemistry and Physics La Trobe Institute for Molecular Science La Trobe University Melbourne Victoria 3086 Australia
| | - Mohammad A. Haghighatbin
- Department of Chemistry and Physics La Trobe Institute for Molecular Science La Trobe University Melbourne Victoria 3086 Australia
| | - Conor F. Hogan
- Department of Chemistry and Physics La Trobe Institute for Molecular Science La Trobe University Melbourne Victoria 3086 Australia
| | - Michael S. Scholz
- School of Chemistry University of Melbourne Parkville Victoria 3010 Australia
| | - James N. Bull
- School of Chemistry University of Melbourne Parkville Victoria 3010 Australia
| | - Evan J. Bieske
- School of Chemistry University of Melbourne Parkville Victoria 3010 Australia
| | - David J. D. Wilson
- Department of Chemistry and Physics La Trobe Institute for Molecular Science La Trobe University Melbourne Victoria 3086 Australia
| | - Jason L. Dutton
- Department of Chemistry and Physics La Trobe Institute for Molecular Science La Trobe University Melbourne Victoria 3086 Australia
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49
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Bull JN, Carrascosa E, Scholz MS, Coughlan NJA, Bieske EJ. Online measurement of photoisomerisation efficiency in solution using ion mobility mass spectrometry. Analyst 2017; 142:2100-2103. [DOI: 10.1039/c7an00398f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A new method for probing the photoisomerisation of molecules in solution using ion mobility mass spectrometry is described and demonstrated with a azoheteroarene photoswitch.
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Affiliation(s)
- James N. Bull
- School of Chemistry
- University of Melbourne
- Melbourne
- Australia
| | | | | | | | - Evan J. Bieske
- School of Chemistry
- University of Melbourne
- Melbourne
- Australia
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50
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Bull JN, Scholz MS, Coughlan NJA, Bieske EJ. Isomerisation of an intramolecular hydrogen-bonded photoswitch: protonated azobis(2-imidazole). Phys Chem Chem Phys 2017; 19:12776-12783. [DOI: 10.1039/c7cp01733b] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Reversible E–Z photoswitching of a protonated azoheteroarene is demonstrated using ion mobility mass spectrometry.
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Affiliation(s)
- James N. Bull
- School of Chemistry
- University of Melbourne
- Parkville
- Australia
| | | | | | - Evan J. Bieske
- School of Chemistry
- University of Melbourne
- Parkville
- Australia
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