1
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Gaba NP, de Moura CEV, Majumder R, Sokolov AY. Simulating transient X-ray photoelectron spectra of Fe(CO) 5 and its photodissociation products with multireference algebraic diagrammatic construction theory. Phys Chem Chem Phys 2024; 26:15927-15938. [PMID: 38805029 DOI: 10.1039/d4cp00801d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Accurate simulations of transient X-ray photoelectron spectra (XPS) provide unique opportunities to bridge the gap between theory and experiment in understanding the photoactivated dynamics in molecules and materials. However, simulating X-ray photoelectron spectra along a photochemical reaction pathway is challenging as it requires accurate description of electronic structure incorporating core-hole screening, orbital relaxation, electron correlation, and spin-orbit coupling in excited states or at nonequilibrium ground-state geometries. In this work, we employ the recently developed multireference algebraic diagrammatic construction theory (MR-ADC) to investigate the core-ionized states and X-ray photoelectron spectra of Fe(CO)5 and its photodissociation products (Fe(CO)4, Fe(CO)3) following excitation with 266 nm light. The simulated transient Fe 3p and CO 3σ XPS spectra incorporating spin-orbit coupling and high-order electron correlation effects are shown to be in a good agreement with the experimental measurements by Leitner et al. [J. Chem. Phys., 2018, 149, 044307]. Our calculations suggest that core-hole screening, spin-orbit coupling, and ligand-field splitting effects are similarly important in reproducing the experimentally observed chemical shifts in transient Fe 3p XPS spectra of iron carbonyl complexes. Our results also demonstrate that the MR-ADC methods can be very useful in interpreting the transient XPS spectra of transition metal compounds.
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Affiliation(s)
- Nicholas P Gaba
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, 43210, USA.
| | - Carlos E V de Moura
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, 43210, USA.
| | - Rajat Majumder
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, 43210, USA.
| | - Alexander Yu Sokolov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, 43210, USA.
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2
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Wang T, Zhang Z, Yan W, Jiang S, Li S, Zhuang J, Xie H, Li G, Jiang L. Spectroscopic Characterization of Highly Excited Neutral Chromium Tricarbonyl. J Phys Chem A 2024; 128:3321-3328. [PMID: 38634151 DOI: 10.1021/acs.jpca.4c01120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2024]
Abstract
Spectroscopic characterization of highly excited neutral transition-metal complexes is important for understanding the multifaceted reaction mechanisms between metals and ligands. In this work, the reactions of neutral chromium atoms with carbon monoxide were probed by size-specific infrared spectroscopy. Interestingly, Cr(CO)3 was found to have an unprecedented 7A2″ septet excited state rather than the singlet ground state. A combination of experiment and theory shows that the gas-phase formation of this highly excited Cr(CO)3 is facile both thermodynamically and kinetically. Electronic structure and bonding analyses indicate that the valence electrons of Cr atoms in the septet Cr(CO)3 are in a relatively stable configuration, which facilitate the highly excited structure and the planar geometric shape (D3h symmetry). The observed septet Cr(CO)3 affords a paradigm for exploring the structure, properties, and formation mechanism of a large variety of excited neutral compounds.
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Affiliation(s)
- Tiantong Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhaoyan Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenhui Yan
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuai Jiang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shangdong Li
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jianxing Zhuang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hua Xie
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Gang Li
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Ling Jiang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Hefei National Laboratory, Hefei 230088, China
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3
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Nagamori K, Haze M, Okuda Y, Yamasaki K, Kohguchi H. Primary and Secondary Processes in the Ultraviolet Photodissociation of CpCo(CO) 2 (Cyclopentadienylcobalt Dicarbonyl). J Phys Chem A 2023; 127:9921-9931. [PMID: 37972309 DOI: 10.1021/acs.jpca.3c04455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
We investigated the photodissociation dynamics of CpCo(CO)2 (cyclopentadienylcobalt dicarbonyl) in metal-to-ligand charge transfer (MLCT) bands. By employing DFT calculations, the absorption band (210-240 nm) was characterized as a charge transfer from the Co center to the Cp (cyclopentadienyl, C5H5) ligand. Ion imaging was utilized to analyze the CO fragments and coordinatively unsaturated complexes (CpCoCO, CpCo, and CoC3H3) across the entire MLCT band. Measuring the production yields of individual unsaturated complexes as a function of photolysis wavelength by considering wavelength dependence indicated the involvement of several photochemical pathways: the first photodissociation and sequential dissociation of CpCo(CO)2, and the second photodissociation of unsaturated intermediates within the pulse duration of the photolysis laser. The recoil velocity shifts of CpCo and CoC3H3 were attributed to the onset of the sequential dissociation of CpCoCO. Evidence for the second photodissociation of CpCoCO was obtained through the matching of linear momenta between the CO(v = 0, 1) and CpCo fragments. The DFT calculations performed to determine the electronic structures and potential energy curves for photoinduced CO loss in CpCo(CO)2 and CpCoCO supported our interpretation of the experimental results. This study presents a practical approach to selectively detecting specific processes among the mixture of products and intermediates when photolyzing transition-metal carbonyls, as their concurrent generation is unavoidable in laser-based experiments.
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Affiliation(s)
- Keigo Nagamori
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Misato Haze
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Yuuka Okuda
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Katsuyoshi Yamasaki
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Hiroshi Kohguchi
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
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4
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Ma Z, Chen L, Xu C, Fournier JA. Two-Dimensional Infrared Spectroscopy of Isolated Molecular Ions. J Phys Chem Lett 2023; 14:9683-9689. [PMID: 37871134 DOI: 10.1021/acs.jpclett.3c02661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Two-dimensional infrared (2D IR) spectroscopy of mass-selected, cryogenically cooled molecular ions is presented. Nonlinear response pathways, encoded in the time-domain photodissociation action response of weakly bound N2 messenger tags, were isolated using pulse shaping techniques following excitation with four collinear ultrafast IR pulses. 2D IR spectra of Re(CO)3(CH3CN)3+ ions capture off-diagonal cross-peak bleach signals between the asymmetric and symmetric carbonyl stretching transitions. These cross peaks display intensity variations as a function of pump-probe delay time due to coherent coupling between the vibrational modes. Well-resolved 2D IR features in the congested fingerprint region of protonated caffeine (C8H10N4O2H+) are also reported. Importantly, intense cross-peak signals were observed at 3 ps waiting time, indicating that tag-loss dynamics are not competing with the measured nonlinear signals. These demonstrations pave the way for more precise studies of molecular interactions and dynamics that are not easily obtainable with current condensed-phase methodologies.
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Affiliation(s)
- Zifan Ma
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Liangyi Chen
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Chuzhi Xu
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Joseph A Fournier
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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5
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Chen L, Ma Z, Fournier JA. Ultrafast transient vibrational action spectroscopy of cryogenically cooled ions. J Chem Phys 2023; 159:041101. [PMID: 37486043 DOI: 10.1063/5.0155490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 05/25/2023] [Indexed: 07/25/2023] Open
Abstract
Ultrafast transient vibrational action spectra of cryogenically cooled Re(CO)3(CH3CN)3+ ions are presented. Nonlinear spectra were collected in the time domain by monitoring the photodissociation of a weakly bound N2 messenger tag as a function of delay times and phases between a set of three infrared pulses. Frequency-resolved spectra in the carbonyl stretch region show relatively strong bleaching signals that oscillate at the difference frequency between the two observed vibrational features as a function of the pump-probe waiting time. This observation is consistent with the presence of nonlinear pathways resulting from underlying cross-peak signals between the coupled symmetric-asymmetric C≡O stretch pair. The successful demonstration of frequency-resolved ultrafast transient vibrational action spectroscopy of dilute molecular ion ensembles provides an exciting, new framework for the study of molecular dynamics in isolated, complex molecular ion systems.
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Affiliation(s)
- Liangyi Chen
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, USA
| | - Zifan Ma
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, USA
| | - Joseph A Fournier
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, USA
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6
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Satterthwaite L, Koumarianou G, Carroll PB, Sedlik RJ, Wang I, McCarthy MC, Patterson D. Low-Temperature Gas-Phase Kinetics of Ethanol-Methanol Heterodimer Formation. J Phys Chem A 2023; 127:4096-4102. [PMID: 37119198 PMCID: PMC10184117 DOI: 10.1021/acs.jpca.3c01312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
The structures of gas-phase noncovalently bound clusters have long been studied in supersonic expansions. This method of study, while providing a wealth of information about the nature of noncovalent bonds, precludes observation of the formation of the cluster, as the clusters form just after the orifice of the pulsed valve. Here, we directly observe formation of ethanol-methanol dimers via microwave spectroscopy in a controlled cryogenic environment. Time profiles of the concentration of reagents in the cell yielded gas-phase reaction rate constants of kMe-g = (2.8 ± 1.4) × 10-13 cm3 molecule-1 s-1 and kMe-t = (1.6 ± 0.8) × 10-13 cm3 molecule-1 s-1 for the pseudo-second-order ethanol-methanol dimerization reaction at 8 K. The relaxation cross section between the gauche and trans conformers of ethanol was also measured using the same technique. In addition, thermodynamic relaxation between conformers of ethanol over time allowed for selection of conformer stoichiometry in the ethanol-methanol dimerization reaction, but no change in the ratio of dimer conformers was observed with changing ethanol monomer stoichiometry.
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Affiliation(s)
- Lincoln Satterthwaite
- Department of Chemistry and Biochemistry, Building 232, University of California, Santa Barbara, California 93106, United States
| | - Greta Koumarianou
- Department of Chemistry and Biochemistry, Building 232, University of California, Santa Barbara, California 93106, United States
| | - P Brandon Carroll
- Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, Massachusetts 02138, United States
| | - Robert J Sedlik
- Physics Department, Broida Hall, University of California, Santa Barbara, California 93106, United States
| | - Irene Wang
- Physics Department, Broida Hall, University of California, Santa Barbara, California 93106, United States
| | - Michael C McCarthy
- Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, Massachusetts 02138, United States
| | - David Patterson
- Physics Department, Broida Hall, University of California, Santa Barbara, California 93106, United States
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7
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Keat TJ, Coxon DJL, Staniforth M, Dale MW, Stavros VG, Newton ME, Lloyd-Hughes J. Dephasing Dynamics across Different Local Vibrational Modes and Crystalline Environments. PHYSICAL REVIEW LETTERS 2022; 129:237401. [PMID: 36563209 DOI: 10.1103/physrevlett.129.237401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/18/2022] [Accepted: 10/20/2022] [Indexed: 06/17/2023]
Abstract
The perturbed free induction decay (PFID) observed in ultrafast infrared spectroscopy was used to unveil the rates at which different vibrational modes of the same atomic-scale defect can interact with their environment. The N_{3}VH^{0} defect in diamond provided a model system, allowing a comparison of stretch and bend vibrational modes within different crystal lattice environments. The observed bend mode (first overtone) exhibited dephasing times T_{2}=2.8(1) ps, while the fundamental stretch mode had surprisingly faster dynamics T_{2}<1.7 ps driven by its more direct perturbation of the crystal lattice, with increased phonon coupling. Further, at high defect concentrations the stretch mode's dephasing rate was enhanced. The ability to reliably measure T_{2} via PFID provides vital insights into how vibrational systems interact with their local environment.
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Affiliation(s)
- T J Keat
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
- Warwick Centre for Doctoral Training in Diamond Science and Technology, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - D J L Coxon
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
- EPSRC Centre for Doctoral Training in Diamond Science and Technology, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - M Staniforth
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - M W Dale
- De Beers Group, Belmont Road, Maidenhead SL6 6JW, United Kingdom
| | - V G Stavros
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - M E Newton
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
- Warwick Centre for Doctoral Training in Diamond Science and Technology, University of Warwick, Coventry CV4 7AL, United Kingdom
- EPSRC Centre for Doctoral Training in Diamond Science and Technology, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - J Lloyd-Hughes
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
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8
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Chakraborty P, Liu Y, McClung S, Weinacht T, Matsika S. Nonadiabatic Excited State Dynamics of Organic Chromophores: Take-Home Messages. J Phys Chem A 2022; 126:6021-6031. [PMID: 36069531 DOI: 10.1021/acs.jpca.2c04671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nonadiabatic excited state dynamics are important in a variety of processes. Theoretical and experimental developments have allowed for a great progress in this area, while combining the two is often necessary and the best approach to obtain insight into the photophysical behavior of molecules. In this Feature Article we use examples of our recent work combining time-resolved photoelectron spectroscopy with theoretical nonadiabatic dynamics to highlight important lessons we learned. We compare the nonadiabatic excited state dynamics of three different organic molecules with the aim of elucidating connections between structure and dynamics. Calculations and measurements are compared for uracil, 1,3-cyclooctadiene, and 1,3-cyclohexadiene. The comparison highlights the role of rigidity in influencing the dynamics and the difficulty of capturing the dynamics accurately with calculations.
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Affiliation(s)
- Pratip Chakraborty
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States.,Division of Theoretical Chemistry and Biology, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden
| | - Yusong Liu
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, United States.,Stanford PULSE Institute, SLAC National Laboratory, Menlo Park, California 94025, United States
| | - Samuel McClung
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, United States
| | - Thomas Weinacht
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, United States
| | - Spiridoula Matsika
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
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9
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Cole-Filipiak NC, Troß J, Schrader P, McCaslin LM, Ramasesha K. Ultrafast infrared transient absorption spectroscopy of gas-phase Ni(CO) 4 photodissociation at 261 nm. J Chem Phys 2022; 156:144306. [DOI: 10.1063/5.0080844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We employ ultrafast mid-infrared transient absorption spectroscopy to probe the rapid loss of carbonyl ligands from gas-phase nickel tetracarbonyl following ultraviolet photoexcitation at 261 nm. Here, nickel tetracarbonyl undergoes prompt dissociation to produce nickel tricarbonyl in a singlet excited state; this electronically excited tricarbonyl loses another CO group over tens of picoseconds. Our results also suggest the presence of a parallel, concerted dissociation mechanism to produce nickel dicarbonyl in a triplet excited state, which likely dissociates to nickel monocarbonyl. Mechanisms for the formation of these photoproducts in multiple electronic excited states are theoretically predicted with one-dimensional cuts through the potential energy surfaces and computation of spin–orbit coupling constants using equation of motion coupled cluster methods (EOM-CC) and coupled cluster theory with single and double excitations (CCSD). Bond dissociation energies are calculated with CCSD, and anharmonic frequencies of ground and excited state species are computed using density functional theory (DFT) and time-dependent density functional theory (TD-DFT).
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Affiliation(s)
- Neil C. Cole-Filipiak
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, USA
| | - Jan Troß
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, USA
| | - Paul Schrader
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, USA
| | - Laura M. McCaslin
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, USA
| | - Krupa Ramasesha
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, USA
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10
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Banerjee A, Coates MR, Kowalewski M, Wikmark H, Jay RM, Wernet P, Odelius M. Photoinduced bond oscillations in ironpentacarbonyl give delayed synchronous bursts of carbonmonoxide release. Nat Commun 2022; 13:1337. [PMID: 35288563 PMCID: PMC8921231 DOI: 10.1038/s41467-022-28997-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 02/21/2022] [Indexed: 12/26/2022] Open
Abstract
Early excited state dynamics in the photodissociation of transition metal carbonyls determines the chemical nature of short-lived catalytically active reaction intermediates. However, time-resolved experiments have not yet revealed mechanistic details in the sub-picosecond regime. Hence, in this study the photoexcitation of ironpentacarbonyl Fe(CO)5 is simulated with semi-classical excited state molecular dynamics. We find that the bright metal-to-ligand charge-transfer (MLCT) transition induces synchronous Fe-C oscillations in the trigonal bipyramidal complex leading to periodically reoccurring release of predominantly axial CO. Metaphorically the photoactivated Fe(CO)5 acts as a CO geyser, as a result of dynamics in the potential energy landscape of the axial Fe-C distances and non-adiabatic transitions between manifolds of bound MLCT and dissociative metal-centered (MC) excited states. The predominant release of axial CO ligands and delayed release of equatorial CO ligands are explained in a unified mechanism based on the σ*(Fe-C) anti-bonding character of the receiving orbital in the dissociative MC states. The photodissociation of transition metal carbonyls is involved in catalysis and synthetic processes. Here the authors, using semi-classical excited state molecular dynamics, observe details of the early stage dynamics in the photodissociation of Fe(CO)5, including synchronous bursts of CO at periodic intervals of 90 femtoseconds.
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Nagamori K, Haze M, Nakata H, Zingsheim O, Yamasaki K, Kohguchi H. Generation of Highly Vibrationally Excited CO in Sequential Photodissociation of Iron Carbonyl Complexes. J Phys Chem A 2022; 126:306-313. [PMID: 35007077 DOI: 10.1021/acs.jpca.1c09922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ultraviolet photochemistry of iron pentacarbonyl, Fe(CO)5, was investigated with resonantly enhanced multiphoton ionization (REMPI) spectroscopy and ion imaging. The REMPI spectrum of CO photofragments, generated by ultraviolet irradiation of Fe(CO)5, showed the generation in the highly vibrationally excited states with v = 11-15. Analysis of the band intensities observed in the 213-235 nm region indicated that the high-v CO generation was maximized at around 220 nm. Generation yields of the coordinatively unsaturated intermediates, Fe(CO)n=1-4, were measured as a function of the photolysis wavelength using a nonresonant detection scheme. The yield spectrum of FeCO was correlated with that of the high-v CO fragments, suggesting high-v CO generation in the photodissociation of FeCO. The density functional theory calculations of the excited states of FeCO showed an intense photoabsorption to the metal-centered state near 220 nm. The theoretical results were consistent with the interpretation of FeCO + hν → Fe + high-v CO, which was experimentally indicated. The momentum distribution obtained from the velocity distributions of Fe, Fe(CO)4, and CO fragments further supported that Fe is the counter-product of the high-v CO fragment. The present results provided selective observation of the photochemistry of the unsaturated iron carbonyl complexes, which has not been well elucidated in laser-based experiments because of the uncontrollable sequential photodissociation producing mixed Fe(CO)n intermediates.
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Affiliation(s)
- Keigo Nagamori
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Misato Haze
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Hiroyuki Nakata
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Oliver Zingsheim
- I. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, 50937 Köln, Germany
| | - Katsuyoshi Yamasaki
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Hiroshi Kohguchi
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
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12
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Thon R, Chin W, Chamma D, Jonusas M, Galaup JP, Crépin C. Vibrational dynamics of iron pentacarbonyl in cryogenic matrices. J Chem Phys 2022; 156:024301. [PMID: 35032984 DOI: 10.1063/5.0073080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Iron pentacarbonyl is a textbook example of fluxionality. We trap the molecule in cryogenic matrices to study the vibrational dynamics of CO stretching modes involved in the fluxional rearrangement. The infrared spectrum in Ar and N2 is composed of about ten narrow bands in the spectral range of interest, indicating the population of various lattice sites and a lowering of the molecular symmetry in the trapping sites. The vibrational dynamics is explored by means of infrared stimulated photon echoes at the femtosecond scale. Vibrational dephasing and population relaxation times are obtained. The non-linear signals exhibit strong oscillations useful to disentangle the site composition of the absorption spectrum. The population relaxation involves at least two characteristic times. An evolution of the photon echo signals with the waiting time is observed. The behavior of all the signals can be reproduced within a simple model that describes the population relaxation occurring in two steps: relaxation of v = 1 (population time T1 < 100 ps) and return to v = 0 (recovery time > 1 ns). These two steps explain the evolution of the oscillations with the waiting time in the photon echo signals. These results discard fluxional rearrangement on the time scale of hundreds of ps in our samples. Dephasing times are of the same order of magnitude as T1: dephasing processes due to the matrix environment are rather inefficient. The photon echo experiments also reveal that intermolecular resonant vibrational energy transfers between guest molecules occur at the hundreds of ps time scale in concentrated samples (guest/host > 104).
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Affiliation(s)
- Raphaël Thon
- Institut des Sciences Moléculaires d'Orsay, UMR8214, CNRS-Université Paris-Saclay, F-91405 Orsay, France
| | - Wutharath Chin
- Institut des Sciences Moléculaires d'Orsay, UMR8214, CNRS-Université Paris-Saclay, F-91405 Orsay, France
| | - Didier Chamma
- Institut des Sciences Moléculaires d'Orsay, UMR8214, CNRS-Université Paris-Saclay, F-91405 Orsay, France
| | - Mindaugas Jonusas
- Institut des Sciences Moléculaires d'Orsay, UMR8214, CNRS-Université Paris-Saclay, F-91405 Orsay, France
| | - Jean-Pierre Galaup
- Institut des Sciences Moléculaires d'Orsay, UMR8214, CNRS-Université Paris-Saclay, F-91405 Orsay, France
| | - Claudine Crépin
- Institut des Sciences Moléculaires d'Orsay, UMR8214, CNRS-Université Paris-Saclay, F-91405 Orsay, France
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13
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Mascarenhas EJ, Fondell M, Büchner R, Eckert S, Vaz da Cruz V, Föhlisch A. Photo-Induced Ligand Substitution of Cr(CO) 6 in 1-Pentanol Probed by Time Resolved X-Ray Absorption Spectroscopy. Phys Chem Chem Phys 2022; 24:17979-17985. [PMID: 35737440 PMCID: PMC9348521 DOI: 10.1039/d1cp05834g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cr(CO)6 was investigated by X-ray absorption spectroscopy. The spectral signature at the metal edge provides information about the back-bonding of the metal in this class of complexes. Among the processes it participates in is ligand substitution in which a carbonyl ligand is ejected through excitation to a metal to ligand charge transfer (MLCT) band. The unsaturated carbonyl Cr(CO)5 is stabilized by solution media in square pyramidal geometry and further reacts with the solvent. Multi-site-specific probing after photoexcitation was used to investigate the ligand substitution photoreaction process which is a common first step in catalytic processes involving metal carbonyls. The data were analysed with the aid of TD-DFT computations for different models of photoproducts and signatures for ligand rearrangement after substitution were found. The rearrangement was found to occur in about 790 ps in agreement with former studies of the photoreaction. The photo-induced ligand substitution reaction of Cr(CO)6 in 1-pentanol was investigated using time-resolved X-ray absorption spectroscopy. The results point to ligand rearrangement after photoexcitation.![]()
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Affiliation(s)
- Eric J Mascarenhas
- Universität Potsdam, Institut für Physik und Astronomie, 14476 Potsdam, Germany.
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Methods and Instrumentation for Synchrotron Radiation Research, 12489 Berlin, Germany
| | - Mattis Fondell
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Methods and Instrumentation for Synchrotron Radiation Research, 12489 Berlin, Germany
| | - Robby Büchner
- Universität Potsdam, Institut für Physik und Astronomie, 14476 Potsdam, Germany.
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Methods and Instrumentation for Synchrotron Radiation Research, 12489 Berlin, Germany
| | - Sebastian Eckert
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Methods and Instrumentation for Synchrotron Radiation Research, 12489 Berlin, Germany
| | - Vinícius Vaz da Cruz
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Methods and Instrumentation for Synchrotron Radiation Research, 12489 Berlin, Germany
| | - Alexander Föhlisch
- Universität Potsdam, Institut für Physik und Astronomie, 14476 Potsdam, Germany.
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Methods and Instrumentation for Synchrotron Radiation Research, 12489 Berlin, Germany
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14
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Linguerri R, Olsson E, Nyman G, Hochlaf M, Eland JHD, Feifel R. Unimolecular Double Photoionization-Induced Processes in Iron Pentacarbonyl. Inorg Chem 2021; 60:17966-17975. [PMID: 34699196 PMCID: PMC8653154 DOI: 10.1021/acs.inorgchem.1c02533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
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The dissociations
of nascent Fe(CO)5++ ions
created by 40.81 eV photoionization of iron pentacarbonyl have been
examined using threefold and fourfold electron–ion coincidence
measurements. The energies and forms of the ions have been explored
by high-level calculations, revealing several new structures. The
most stable form of Fe(CO)5++ has a quite different
geometry from that of the neutral molecule. The dissociation pattern
can be modeled as a sequence of CO evaporations followed by two-body
charge separations. Each Fe(CO)n++ (n = 1–4) dication is stable in a restricted
energy range; as its internal energy increases, it first ejects a
neutral CO, then loses CO+ by charge separation at higher
energy. In the initial stages, charge-retaining CO evaporations dominate
over charge separation, but the latter become more competitive as
the number of residual CO ligands decreases. At energies where ionization
is mainly from the CO ligands, new Fe–C and C–C bonds
are created by a mechanism which might be relevant to catalysis by
Fe. Dissociations of nascent Fe(CO)5++ ions by sequential CO evaporations, leading (in restricted
energy
ranges) to stable Fe(CO)n++ (n = 1−4) dicationic species. At energies
where ionization is mainly from the CO ligands, new Fe−C and
C−C bonds are created by a mechanism which might be relevant
to catalysis by Fe.
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Affiliation(s)
- Roberto Linguerri
- COSYS/LISIS, Université Gustave Eiffel, 5 Bd Descartes, 77454, Champs sur Marne, France
| | - Emelie Olsson
- Department of Physics, University of Gothenburg, Origovägen 6B, 412 58 Gothenburg, Sweden
| | - Gunnar Nyman
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Majdi Hochlaf
- COSYS/LISIS, Université Gustave Eiffel, 5 Bd Descartes, 77454, Champs sur Marne, France
| | - John H D Eland
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, OX1 3QZ Oxford, U.K
| | - Raimund Feifel
- Department of Physics, University of Gothenburg, Origovägen 6B, 412 58 Gothenburg, Sweden
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15
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Farrow GA, Quick M, Kovalenko SA, Wu G, Sadler A, Chekulaev D, Chauvet AAP, Weinstein JA, Ernsting NP. On the intersystem crossing rate in a Platinum(II) donor-bridge-acceptor triad. Phys Chem Chem Phys 2021; 23:21652-21663. [PMID: 34580688 DOI: 10.1039/d1cp03471e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The rates of ultrafast intersystem crossing in acceptor-bridge-donor molecules centered on Pt(II) acetylides are investigated. Specifically, a Pt(II) trans-acetylide triad NAP--Pt--Ph-CH2-PTZ [1], with acceptor 4-ethynyl-N-octyl-1,8-naphthalimide (NAP) and donor phenothiazine (PTZ), is examined in detail. We have previously shown that optical excitation in [1] leads to a manifold of singlet charge-transfer states, S*, which evolve via a triplet charge-transfer manifold into a triplet state 3NAP centered on the acceptor ligand and partly to a charge-separated state 3CSS (NAP--Pt-PTZ+). A complex cascade of electron transfer processes was observed, but intersystem crossing (ISC) rates were not explicitly resolved due to lack of spin selectivity of most ultrafast spectroscopies. Here we revisit the question of ISC with a combination and complementary analysis of (i) transient absorption, (ii) ultrafast broadband fluorescence upconversion, FLUP, which is only sensitive to emissive states, and (iii) femtosecond stimulated Raman spectroscopy, FSR. Raman resonance conditions allow us to observe S* and 3NAP exclusively by FSR, through vibrations which are pertinent only to these two states. This combination of methods enabled us to extract the intersystem crossing rates that were not previously accessible. Multiple timescales (1.6 ps to ∼20 ps) are associated with the rise of triplet species, which can now be assigned conclusively to multiple ISC pathways from a manifold of hot charge-transfer singlet states. The analysis is consistent with previous transient infrared spectroscopy data. A similar rate of ISC, up to 20 ps, is observed in the trans-acetylide NAP--Pt--Ph [2] which maintains two acetylide groups across the platinum center but lacks a donor unit, whilst removal of one acetylide group in mono-acetylide NAP--Pt-Cl [3] leads to >10-fold deceleration of the intersystem crossing process. Our work provides insight on the intersystem crossing dynamics of the organo-metallic complexes, and identifies a general method based on complementary ultrafast spectroscopies to disentangle complex spin, electronic and vibrational processes following photoexcitation.
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Affiliation(s)
- G A Farrow
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
| | - M Quick
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
| | - S A Kovalenko
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
| | - G Wu
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
| | - A Sadler
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
| | - D Chekulaev
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
| | - A A P Chauvet
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
| | - J A Weinstein
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
| | - N P Ernsting
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
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