1
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Oang KY, Park S, Moon J, Park E, Lee HK, Sato T, Nozawa S, Adachi SI, Kim J, Kim J, Sohn JH, Ihee H. Extracting Kinetics and Thermodynamics of Molecules without Heavy Atoms via Time-Resolved Solvent Scattering Signals. J Phys Chem Lett 2023; 14:3103-3110. [PMID: 36951437 DOI: 10.1021/acs.jpclett.3c00041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Time-resolved X-ray liquidography (TRXL) has emerged as a powerful technique for studying the structural dynamics of small molecules and macromolecules in liquid solutions. However, TRXL has limited sensitivity for small molecules containing light atoms only, whose signal has lower contrast compared with the signal from solvent molecules. Here, we present an alternative approach to bypass this limitation by detecting the change in solvent temperature resulting from a photoinduced reaction. Specifically, we analyzed the heat dynamics of TRXL data obtained from p-hydroxyphenacyl diethyl phosphate (HPDP). This analysis enabled us to experimentally determine the number of intermediates and their respective enthalpy changes, which can be compared to theoretical enthalpies to identify the intermediates. This work demonstrates that TRXL can be used to uncover the kinetics and reaction pathways for small molecules without heavy atoms even if the scattering signal from the solute molecules is buried under the strong solvent scattering signal.
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Affiliation(s)
- Key Young Oang
- Radiation Center for Ultrafast Science, Korea Atomic Energy Research Institute (KAERI), Daejeon 34057, Republic of Korea
| | - Sungjun Park
- Department of Chemistry and KI for BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
- Center for Advanced Reaction Dynamics, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Jiwon Moon
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Eunji Park
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Hyun Kyung Lee
- Department of Chemistry, College of Natural Sciences, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Tokushi Sato
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Shunsuke Nozawa
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Shin-Ichi Adachi
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
- Department of Materials Structure Science, School of High Energy Accelerator Science, The Graduate University for Advanced Studies, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Joonghan Kim
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Jeongho Kim
- Department of Chemistry, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea
| | - Jeong-Hun Sohn
- Department of Chemistry, College of Natural Sciences, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Hyotcherl Ihee
- Department of Chemistry and KI for BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
- Center for Advanced Reaction Dynamics, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
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2
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Kromer S, Roy S, Yarnell JE, Taliaferro CM, Castellano FN. Excited state processes of dinuclear Pt(II) complexes bridged by 8-hydroxyquinoline. Dalton Trans 2023; 52:4008-4016. [PMID: 36880277 DOI: 10.1039/d3dt00348e] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
Dinuclear d8 Pt(II) complexes, where two mononuclear square planar Pt(II) units are bridged in an "A-frame" geometry, possess photophysical properties characterised by either metal-to-ligand-(MLCT) or metal-metal-ligand-to-ligand charge transfer (MMLCT) transitions determined by the distance between the two Pt(II) centres. When using 8-hydroxyquinoline (8HQH) as the bridging ligand to construct novel dinuclear complexes with general formula [C^NPt(μ-8HQ)]2, where C^N is either 2-phenylpyridine (1) or 7,8-benzoquinoline (2), triplet ligand-centered (3LC) photophysics results echoing that in a mononuclear model chromophore, [Pt(8HQ)2] (3). The lengthened Pt-Pt distances of 3.255 Å (1) and 3.243 Å (2) results in a lowest energy absorption centred around 480 nm assigned as having mixed LC/MLCT character by TD-DFT, mirroring the visible absorption spectrum of 3. Additionally, 1 and 2 exhibit 3LC photoluminescence with limited quantum yields (0.008) from broad transitions centred near 680 nm. Photoexcitation of 1-3 leads to an initially prepared excited state that relaxes within 15 ps to a 3LC excited state centred on the 8HQ bridge, which then persists for several microseconds. All the experimental results correspond well with DFT electronic structure calculations.
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Affiliation(s)
- Sarah Kromer
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA.
| | - Subhangi Roy
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA.
| | - James E Yarnell
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA.
| | - Chelsea M Taliaferro
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA.
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA.
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3
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Myneni H, Jónsson EÖ, Jónsson H, Dohn AO. Polarizable Force Field for Acetonitrile Based on the Single-Center Multipole Expansion. J Phys Chem B 2022; 126:9339-9348. [PMID: 36343220 DOI: 10.1021/acs.jpcb.2c04255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A polarizable potential function describing the interaction between acetonitrile molecules is introduced. The molecules are described as rigid and linear, with three mass sites corresponding to the CH3 group (methyl, Me), the central carbon atom (C), and the nitrogen atom (N). The electrostatic interaction is represented using a single-center multipole expansion as has been done previously for H2O [Wikfeldt et al., Phys. Chem. Chem. Phys. 15, 16542 (2013)], by including multipole moments from dipole up to and including hexadecapole, as well as anisotropic dipole-dipole, dipole-quadrupole, and quadrupole-quadrupole polarizability tensors. The model is free of point charges. The non-electrostatic part is described in a pair-wise fashion by a Born-Mayer repulsion and damped dispersion attraction. The potential function is parameterized to fit the interaction energy of small (CH3CN)n, n = 2-6, clusters calculated using the PBE0 hybrid functional with an additional atomic many-body dispersion contribution. The parameterized potential function is found to compare well with results of the electronic structure calculations of dissociation curves for different dimer orientations and cohesive properties (the equilibrium volume, cohesive energy, and the bulk modulus) of the α-phase of acetonitrile crystal. The average value of the molecular dipole moment obtained in the α-phase is 5.53 D, corresponding to ca. 40% increase as compared to the dipole moment of an isolated acetonitrile molecule, 3.92 D. The calculated densities of solid and liquid acetonitrile turn out to be 8-10% higher than experimental values. This appears to be caused by an overestimate of the atomic many-body dispersion interaction in the density functional calculations used as input in the parametrization of the potential function.
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Affiliation(s)
- Hemanadhan Myneni
- Science Institute and Faculty of Physical Sciences, University of Iceland VR-III, 107Reykjavík, Iceland
| | - Elvar Örn Jónsson
- Science Institute and Faculty of Physical Sciences, University of Iceland VR-III, 107Reykjavík, Iceland
| | - Hannes Jónsson
- Science Institute and Faculty of Physical Sciences, University of Iceland VR-III, 107Reykjavík, Iceland
| | - Asmus Ougaard Dohn
- Science Institute and Faculty of Physical Sciences, University of Iceland VR-III, 107Reykjavík, Iceland
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4
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Stipurin S, Strassner T. Phosphorescent Bimetallic C^C* Platinum(
ii
) Complexes with Bridging Substituted Diphenylformamidinates. Chemistry 2022; 28:e202202227. [PMID: 36284471 PMCID: PMC10092827 DOI: 10.1002/chem.202202227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Indexed: 11/05/2022]
Abstract
A series of phosphorescent bimetallic platinum(II) complexes is presented, which were synthesized by the combination of bidentate cyclometalated N-heterocyclic carbene ligands and different bridging diphenylformamidinates. The complexes were characterized by standard techniques and additionally two solid-state structures could be obtained. Photoluminescence measurements revealed the strong emissive behavior of the compounds with quantum yields of up to 90 % and emission lifetimes of approx. 2 μs. The effect of the substitution pattern in the bridging ligands on the structural and photophysical properties of the complexes was examined in detail and rationalized by density functional theory calculations (PBE0/6-311G*).
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Affiliation(s)
- Sergej Stipurin
- Physikalische Organische Chemie Technische Universität Dresden 01069 Dresden Germany
| | - Thomas Strassner
- Physikalische Organische Chemie Technische Universität Dresden 01069 Dresden Germany
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5
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Zulfikri H, Pápai M, Dohn AO. Simulating the solvation structure of low- and high-spin [Fe(bpy) 3] 2+: long-range dispersion and many-body effects. Phys Chem Chem Phys 2022; 24:16655-16670. [PMID: 35766396 DOI: 10.1039/d2cp00892k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
When characterizing transition metal complexes and their functionalities, the importance of including the solvent as an active participant is becoming more and more apparent. Whereas many studies have evaluated long-range dispersion effects inside organic molecules and organometallics, less is known about their role in solvation. Here, we have analysed the components within solute-solvent and solvent-solvent interactions of one of the most studied iron-based photoswitch model systems, in two spin states. We find that long-range dispersion effects modulate the coordination significantly, and that this is accurately captured by density functional theory models including dispersion corrections. We furthermore correlate gas-phase relaxed complex-water clusters to thermally averaged molecular densities. This shows how the gas-phase interactions translate to solution structure, quantified through 3D molecular densities, angular distributions, and radial distribution functions. We show that finite-size simulation cells can cause the radial distribution functions to have artificially enlarged amplitudes. Finally, we quantify the effects of many-body interactions within the solvent shells, and find that almost a fifth of the total interaction energy of the solute-shell system in the high-spin state comes from many-body contributions, which cannot be captured by by pair-wise additive force field methods.
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Affiliation(s)
- Habiburrahman Zulfikri
- Science Institute and Faculty of Physical Sciences, University of Iceland, VR-III, Reykjavík 107, Iceland.
| | - Mátyás Pápai
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800 Kgs. Lyngby, Denmark
| | - Asmus Ougaard Dohn
- Science Institute and Faculty of Physical Sciences, University of Iceland, VR-III, Reykjavík 107, Iceland. .,Department of Physics, Technical University of Denmark, Fysikvej 307, 2800 Kgs. Lyngby, Denmark
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6
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Kim P, Valentine AJS, Roy S, Mills AW, Castellano FN, Li X, Chen LX. Ultrafast branching in intersystem crossing dynamics revealed by coherent vibrational wavepacket motions in a bimetallic Pt(II) complex. Faraday Discuss 2022; 237:259-273. [PMID: 35642929 DOI: 10.1039/d2fd00009a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ultrafast excited state processes of transition metal complexes (TMCs) are governed by complicated interplays between electronic and nuclear dynamics, which demand a detailed understanding to achieve optimal functionalities of photoactive TMC-based materials for many applications. In this work, we investigated a cyclometalated platinum(II) dimer known to undergo a Pt-Pt bond contraction in the metal-metal-to-ligand-charge-transfer (MMLCT) excited state using femtosecond broadband transient absorption (fs-BBTA) spectroscopy in combination with geometry optimization and normal mode calculations. Using a sub-20 fs pump and broadband probe pulses in fs-BBTA spectroscopy, we were able to correlate the coherent vibrational wavepacket (CVWP) evolution with the stimulated emission (SE) dynamics of the 1MMLCT state. The results demonstrated that the 145 cm-1 CVWP motions with the damping times of ∼0.9 ps and ∼2 ps originate from coherent Pt-Pt stretching vibrations in the singlet and triplet MMLCT states, respectively. On the basis of excited state potential energy surface calculations in our previous work, we rationalized that the CVWP transfer from the Franck-Condon (FC) state to the 3MMLCT state was mediated by a triplet ligand-centered (3LC) intermediate state through two step intersystem crossing (ISC) on a time scale shorter than a period of the Pt-Pt stretching wavepacket motions. Moreover, it was found that the CVWP motion had 110 cm-1 frequency decays with the damping time of ∼0.2 ps, matching the time constant of 0.253 ps, corresponding to a redshift in the SE feature at early times. This observation indicates that the Pt-Pt bond contraction changes the stretching frequency from 110 to 145 cm-1 and stabilizes the 1MMLCT state relative to the 3LC state with a ∼0.2 ps time scale. Thus, the ultrafast ISC from the 1MMLCT to the 3LC states occurs before the Pt-Pt bond shortening. The findings herein provide insight into understanding the impact of Pt-Pt bond contraction on the ultrafast branching of the 1MMLCT population into the direct (1MMLCT → 3MMLCT) and indirect ISC pathways (1MMLCT → 3LC → 3MMLCT) in the Pt(II) dimer. These results revealed intricate excited state electronic and nuclear motions that could steer the reaction pathways with a level of detail that has not been achieved before.
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Affiliation(s)
- Pyosang Kim
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA. .,Chemical Science and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60349, USA
| | - Andrew J S Valentine
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| | - Subhangi Roy
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Alexis W Mills
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Xiaosong Li
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| | - Lin X Chen
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA. .,Chemical Science and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60349, USA
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7
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Jeong H, Ki H, Kim JG, Kim J, Lee Y, Ihee H. Sensitivity of
time‐resolved
diffraction data to changes in internuclear distances and atomic positions. B KOREAN CHEM SOC 2022. [DOI: 10.1002/bkcs.12494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Haeyun Jeong
- Department of Chemistry and KI for the BioCentury Korea Advanced Institute of Science and Technology (KAIST) Daejeon Republic of Korea
| | - Hosung Ki
- Department of Chemistry and KI for the BioCentury Korea Advanced Institute of Science and Technology (KAIST) Daejeon Republic of Korea
- Center for Advanced Reaction Dynamics Institute for Basic Science (IBS) Daejeon Republic of Korea
| | - Jong Goo Kim
- Department of Chemistry and KI for the BioCentury Korea Advanced Institute of Science and Technology (KAIST) Daejeon Republic of Korea
- Center for Advanced Reaction Dynamics Institute for Basic Science (IBS) Daejeon Republic of Korea
| | - Jungmin Kim
- Department of Chemistry and KI for the BioCentury Korea Advanced Institute of Science and Technology (KAIST) Daejeon Republic of Korea
- Center for Advanced Reaction Dynamics Institute for Basic Science (IBS) Daejeon Republic of Korea
| | - Yunbeom Lee
- Department of Chemistry and KI for the BioCentury Korea Advanced Institute of Science and Technology (KAIST) Daejeon Republic of Korea
- Center for Advanced Reaction Dynamics Institute for Basic Science (IBS) Daejeon Republic of Korea
| | - Hyotcherl Ihee
- Department of Chemistry and KI for the BioCentury Korea Advanced Institute of Science and Technology (KAIST) Daejeon Republic of Korea
- Center for Advanced Reaction Dynamics Institute for Basic Science (IBS) Daejeon Republic of Korea
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8
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Roy S, Lopez AA, Yarnell JE, Castellano FN. Metal-Metal-to-Ligand Charge Transfer in Pt(II) Dimers Bridged by Pyridyl and Quinoline Thiols. Inorg Chem 2021; 61:121-130. [PMID: 34955020 DOI: 10.1021/acs.inorgchem.1c02469] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The investigation of two distinct species of square planar dinuclear Pt(II) dimers based on anti-[Pt(C∧N)(μ-N∧S)]2, where C∧N is either 2-phenylpyridine (ppy) or benzo(h)quinoline (bzq) and N∧S is pyridine-2-thiol (pyt), 6-methylpyridine-2-thiol (Mpyt), or 2-quinolinethiol (2QT), is presented. Each molecule was thoroughly characterized with electronic structure calculations, static UV-vis and photoluminescence (PL) spectroscopy, and cyclic voltammetry, along with transient absorbance and time-gated PL experiments. These visible absorbing chromophores feature metal-metal-to-ligand charge-transfer (MMLCT) excited states that originate from intramolecular d8-d8 metal-metal σ-interactions and are manifested in the ground- and excited-state properties of these molecules. All five molecules reported (anti-[Pt(ppy)(μ-Mpyt)]2 could not be isolated), three of which are newly conceived here, possess electronic absorptions past 500 nm and high quantum yield PL emission with spectra extending into the far red (λem > 700 nm), originating from the charge-transfer state in each instance. Each chromophore displays excited-state decay kinetics adequately modeled by single exponentials as recorded using dynamic absorption and PL experiments; each technique yields similar decay kinetics. The combined data illustrate that pyridyl and quinoline-thiolates in conjunction with select cyclometalates represent classes of MMLCT chromophores that exhibit excited-state properties suitable for promoting light-energized chemical reactions and provide a molecular platform suitable for evaluating coherence phenomena in transient metal-metal bond-forming photochemistry.
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Affiliation(s)
- Subhangi Roy
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Antonio A Lopez
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - James E Yarnell
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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9
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Mills AW, Valentine AJS, Hoang K, Roy S, Castellano FN, Chen LX, Li X. General Design Rules for Bimetallic Platinum(II) Complexes. J Phys Chem A 2021; 125:9438-9449. [PMID: 34699219 DOI: 10.1021/acs.jpca.1c05044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of platinum(II) bimetallic complexes were studied to investigate the effects of ligands on both the geometric and electronic structure. Modulating the Pt-Pt distance through the bridging ligand architecture was found to dictate the nature of the lowest energy electronic transitions, localized in one-half of the molecule or delocalized across the entire molecule. By reducing the separation between the platinum atoms, the lowest energy electronic transitions will be dominated by the metal-metal-to-ligand charge transfer transition. Conversely, by increasing the distance between the platinum atoms, the lowest electronic transition will be largely localized metal-to-ligand charge transfer or ligand centered in nature. Additionally, the cyclometalating ligands were observed to have a noticeable stabilizing effect on the triplet excited states as the conjugation increased, arising from geometric reorientation and increased electron delocalization of the ligands. Such stabilization of the triplet state energy has been shown to alter the excited state potential energy landscape as well as the excited state trajectory.
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Affiliation(s)
- Alexis W Mills
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Andrew J S Valentine
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Kevin Hoang
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Subhangi Roy
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Lin X Chen
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States.,Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Xiaosong Li
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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10
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Weingartz NP, Mara MW, Roy S, Hong J, Chakraborty A, Brown-Xu SE, Phelan BT, Castellano FN, Chen LX. Excited-State Bond Contraction and Charge Migration in a Platinum Dimer Complex Characterized by X-ray and Optical Transient Absorption Spectroscopy. J Phys Chem A 2021; 125:8891-8898. [PMID: 34597043 DOI: 10.1021/acs.jpca.1c07201] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Interactions between metal centers in dimeric transition metal complexes (TMCs) play important roles in their excited-state energetics and pathways and, thus, affect their photophysical properties relevant to their applications, for example, photoluminescent materials and photocatalysis. Here, we report electronic and nuclear structural dynamics studies of two photoexcited pyrazolate-bridged [Pt(ppy)(μ-R2pz)]2-type Pt(II) dimers (ppy = 2-phenylpyridine, μ-R2pz = 3,5-substituted pyrazolate): [Pt(ppy)(μ-H2pz)]2 (1) and [Pt(NDI-ppy)(μ-Ph2pz)]2 (2, NDI = 1,4,5,8-naphthalenediimide), both of which have distinct ground-state Pt-Pt distances. X-ray transient absorption (XTA) spectroscopy at the Pt LIII-edge revealed a new d-orbital vacancy due to the one-electron oxidation of the Pt centers in 1 and 2. However, while a transient Pt-Pt contraction was observed in 2, such an effect was completely absent in 1, demonstrating how the excited states of these complexes are determined by the overlap of the Pt (dz2) orbitals, which is tuned by the steric bulk of the pyrazolate R-groups in the 3- and 5-positions. In tandem with analysis of the Pt-Pt distance structural parameter, we observed photoinduced electron transfer in 2 featuring a covalently linked NDI acceptor on the ppy ligand. The formation and subsequent decay of the NDI radical anion absorption signals were detected upon photoexcitation using optical transient absorption spectroscopy. The NDI radical anion decayed on the same time scale, hundreds of picoseconds, as that of the d-orbital vacancy signal of the oxidized Pt-Pt core observed in the XTA measurements. The data indicated an ultrafast formation of the charge-separated state and subsequent charge recombination to the original Pt(II-II) species.
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Affiliation(s)
- Nicholas P Weingartz
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.,Chemical Science and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Michael W Mara
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.,Chemical Science and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Subhangi Roy
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Jiyun Hong
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Arnab Chakraborty
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Samantha E Brown-Xu
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Brian T Phelan
- Chemical Science and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Lin X Chen
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.,Chemical Science and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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11
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Ki H, Choi S, Kim J, Choi EH, Lee S, Lee Y, Yoon K, Ahn CW, Ahn DS, Lee JH, Park J, Eom I, Kim M, Chun SH, Kim J, Ihee H, Kim J. Optical Kerr Effect of Liquid Acetonitrile Probed by Femtosecond Time-Resolved X-ray Liquidography. J Am Chem Soc 2021; 143:14261-14273. [PMID: 34455778 DOI: 10.1021/jacs.1c06088] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Optical Kerr effect (OKE) spectroscopy is a method that measures the time-dependent change of the birefringence induced by an optical laser pulse using another optical laser pulse and has been used often to study the ultrafast dynamics of molecular liquids. Here we demonstrate an alternative method, femtosecond time-resolved X-ray liquidography (fs-TRXL), where the microscopic structural motions related to the OKE response can be monitored using a different type of probe, i.e., X-ray solution scattering. By applying fs-TRXL to acetonitrile and a dye solution in acetonitrile, we demonstrate that different types of molecular motions around photoaligned molecules can be resolved selectively, even without any theoretical modeling, based on the anisotropy of two-dimensional scattering patterns and extra structural information contained in the q-space scattering data. Specifically, the dynamics of reorientational (libration and orientational diffusion) and translational (interaction-induced motion) motions are captured separately by anisotropic and isotropic scattering signals, respectively. Furthermore, the two different types of reorientational motions are distinguished from each other by their own characteristic scattering patterns and time scales. The measured time-resolved scattering signals are in excellent agreement with the simulated scattering signals based on a molecular dynamics simulation for plausible molecular configurations, providing the detailed structural description of the OKE response in liquid acetonitrile.
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Affiliation(s)
- Hosung Ki
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.,Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Seungjoo Choi
- Department of Chemistry, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea
| | - Jungmin Kim
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.,Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Eun Hyuk Choi
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.,Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Seonggon Lee
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.,Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Yunbeom Lee
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.,Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Kihwan Yoon
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Chi Woo Ahn
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.,Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Doo-Sik Ahn
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.,Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Jae Hyuk Lee
- Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Jaeku Park
- Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Intae Eom
- Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Minseok Kim
- Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Sae Hwan Chun
- Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Joonghan Kim
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Hyotcherl Ihee
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.,Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Jeongho Kim
- Department of Chemistry, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea
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12
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Pinter P, Soellner J, Strassner T. Metallophilic Interactions in Bimetallic Cyclometalated Platinum(II) N‐Heterocyclic Carbene Complexes. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100456] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Piermaria Pinter
- Physikalische Organische Chemie Technische Universität Dresden 01069 Dresden Germany
| | - Johannes Soellner
- Physikalische Organische Chemie Technische Universität Dresden 01069 Dresden Germany
| | - Thomas Strassner
- Physikalische Organische Chemie Technische Universität Dresden 01069 Dresden Germany
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13
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Su BK, Wei YC, Chuang WT, Weng SC, Wang SF, Chen DG, Huang ZX, Chi Y, Chou PT. The Observation of Interchain Motion in Self-Assembled Crystalline Platinum(II) Complexes: An Exquisite Case but By No Means the Only One in Molecular Solids. J Phys Chem Lett 2021; 12:7482-7489. [PMID: 34342467 DOI: 10.1021/acs.jpclett.1c01677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In organic and organometallic solids, upon electronic excitation, most intermolecular structural relaxations follow a pathway along the π-π stacking direction or metal-metal bond with significant coupling strength. Differently, we discovered that the self-assembled platinum(II) complexes, Pt(fppz)2, exhibit an unusual interchain contraction. The ground-state and excited-state multiple local minima were distinguished by temperature-dependent excitation/emission spectra, indicating the existence of multiple local minima. The time-resolved emission decay revealed the excited-state structural relaxation lifetime with τobs = 41 ns at 298 K. Temperature-dependent X-ray diffraction analysis showed that the packing geometries contract 0.6 Å along the interchain direction (a-axis) at 50 K compared to the geometries at 298 K. Such structural displacements render the slow internal conversion rate in the excited states. We thus demonstrate the correlation between the packing geometries and the excited-state dynamics of the self-assembled Pt(II) complexes, shedding light on the unique direction of interchain structural deformation of the molecular aggregates.
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Affiliation(s)
- Bo-Kang Su
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Yu-Chen Wei
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Wei-Tsung Chuang
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Shih-Chang Weng
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Sheng-Fu Wang
- Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Deng-Gao Chen
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Zhi-Xuan Huang
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Yun Chi
- Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
- Department of Materials Science and Engineering, Department of Chemistry, and Center of Super-Diamond and Advanced Films, City University of Hong Kong, Kowloon 999077, Hong Kong SAR
| | - Pi-Tai Chou
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
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14
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Kim P, Valentine AJS, Roy S, Mills AW, Chakraborty A, Castellano FN, Li X, Chen LX. Ultrafast Excited-State Dynamics of Photoluminescent Pt(II) Dimers Probed by a Coherent Vibrational Wavepacket. J Phys Chem Lett 2021; 12:6794-6803. [PMID: 34270259 DOI: 10.1021/acs.jpclett.1c01289] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Intricate potential energy surfaces (PESs) of some transition metal complexes (TMCs) pose challenges in mapping out initial excited-state pathways that could influence photochemical outcomes. Ultrafast intersystem crossing (ISC) dynamics of four structurally related platinum(II) dimer complexes were examined by detecting their coherent vibrational wavepacket (CVWP) motions of Pt-Pt stretching mode in the metal-metal-to-ligand-charge-transfer excited states. Structurally dependent CVWP behaviors (frequency, dephasing time, and oscillation amplitudes) were captured by femtosecond transient absorption spectroscopy, analyzed by short-time Fourier transformation, and rationalized by quantum mechanical calculations, revealing dual ISC pathways. The results suggest that the ligands could fine-tune the PESs to influence the proximity of the conical intersections of the excited states with the Franck-Condon state and thus to control the branching ratio of the dual ISC pathways. This comparative study presents future opportunities in control excited-state trajectories of TMCs via ligand structures.
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Affiliation(s)
- Pyosang Kim
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- Chemical Science and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Andrew J S Valentine
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Subhangi Roy
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Alexis W Mills
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Arnab Chakraborty
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Xiaosong Li
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Lin X Chen
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- Chemical Science and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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15
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Pinter P, Soellner J, Strassner T. Photophysical Properties of Phosphorescent Mono- and Bimetallic Platinum(II) Complexes with C∧C* Cyclometalating NHC Ligands. Organometallics 2021. [DOI: 10.1021/acs.organomet.0c00790] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Piermaria Pinter
- Physikalische Organische Chemie, Technische Universität Dresden, 01069 Dresden, Germany
| | - Johannes Soellner
- Physikalische Organische Chemie, Technische Universität Dresden, 01069 Dresden, Germany
| | - Thomas Strassner
- Physikalische Organische Chemie, Technische Universität Dresden, 01069 Dresden, Germany
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16
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Mewes L, Ingle RA, Megow S, Böhnke H, Baranoff E, Temps F, Chergui M. Ultrafast Intersystem Crossing and Structural Dynamics of [Pt(ppy)(μ- tBu 2pz)] 2. Inorg Chem 2020; 59:14643-14653. [PMID: 32677823 DOI: 10.1021/acs.inorgchem.0c00902] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Intersystem crossing (ISC) rates of transition-metal complexes are determined by the complex interplay of a molecule's electronic and structural dynamics. To broaden our understanding of these key factors, we investigate the case of the prototypical d8-d8 dimetal complex [Pt(ppy)(μ-tBu2pz)]2 using broad-band transient absorption anisotropy in combination with ultrafast fluorescence up-conversion and ab initio calculations. We find that, upon excitation of the molecule's metal-metal-to-ligand charge-transfer transition, ISC occurs in hundreds of femtoseconds from the lowest excited singlet state S1 to the triplet state T2, from where the energy relaxes to the lowest energy triplet state T1. ISC to the T2 state, rather than T1, is further rationalized through supporting arguments. Observed vibrational coherences along the Pt-Pt mode are attributed to the formation of nuclear wavepackets on the ground and excited electronic states that dephase prior to ISC because of the structural flexibility of the complex. Beyond demonstrating the relationship between the energy relaxation and structural dynamics of [Pt(ppy)(μ-tBu2pz)]2, our results provide new insights into the photoinduced dynamics of d8-d8 dimetal complexes more generally.
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Affiliation(s)
- Lars Mewes
- Laboratoire de spectroscopie ultrarapide and Lausanne Centre for Ultrafast Spectroscopy, Ecole Polytechnique Fédérale de Lausanne, ISIC, FSB Station 6, Lausanne CH-1015, Switzerland
| | - Rebecca A Ingle
- Laboratoire de spectroscopie ultrarapide and Lausanne Centre for Ultrafast Spectroscopy, Ecole Polytechnique Fédérale de Lausanne, ISIC, FSB Station 6, Lausanne CH-1015, Switzerland
| | - Sebastian Megow
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, Kiel D-24098, Germany
| | - Hendrik Böhnke
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, Kiel D-24098, Germany
| | - Etienne Baranoff
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Friedrich Temps
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, Kiel D-24098, Germany
| | - Majed Chergui
- Laboratoire de spectroscopie ultrarapide and Lausanne Centre for Ultrafast Spectroscopy, Ecole Polytechnique Fédérale de Lausanne, ISIC, FSB Station 6, Lausanne CH-1015, Switzerland
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17
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Miller NA, Michocki LB, Konar A, Alonso-Mori R, Deb A, Glownia JM, Sofferman DL, Song S, Kozlowski PM, Kubarych KJ, Penner-Hahn JE, Sension RJ. Ultrafast XANES Monitors Femtosecond Sequential Structural Evolution in Photoexcited Coenzyme B 12. J Phys Chem B 2020; 124:199-209. [PMID: 31850761 DOI: 10.1021/acs.jpcb.9b09286] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Polarized X-ray absorption near-edge structure (XANES) at the Co K-edge and broadband UV-vis transient absorption are used to monitor the sequential evolution of the excited-state structure of coenzyme B12 (adenosylcobalamin) over the first picosecond following excitation. The initial state is characterized by sub-100 fs sequential changes around the central cobalt. These are polarized first in the y-direction orthogonal to the transition dipole and 50 fs later in the x-direction along the transition dipole. Expansion of the axial bonds follows on a ca. 200 fs time scale as the molecule moves out of the Franck-Condon active region of the potential energy surface. On the same 200 fs time scale there are electronic changes that result in the loss of stimulated emission and the appearance of a strong absorption at 340 nm. These measurements provide a cobalt-centered movie of the excited molecule as it evolves to the local excited-state minimum.
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Affiliation(s)
- Nicholas A Miller
- Department of Chemistry , University of Michigan , 930 N. University Ave. , Ann Arbor , Michigan 48109-1055 , United States
| | - Lindsay B Michocki
- Department of Chemistry , University of Michigan , 930 N. University Ave. , Ann Arbor , Michigan 48109-1055 , United States
| | - Arkaprabha Konar
- Department of Physics , University of Michigan , 450 Church Street , Ann Arbor , Michigan 48109-1040 , United States
| | - Roberto Alonso-Mori
- Linac Coherent Light Source , SLAC National Accelerator Laboratory , 2575 Sand Hill Road , Menlo Park , California 94025 , United States
| | - Aniruddha Deb
- Department of Chemistry , University of Michigan , 930 N. University Ave. , Ann Arbor , Michigan 48109-1055 , United States.,Department of Biophysics , University of Michigan , 930 N. University Ave. , Ann Arbor , Michigan 48109-1055 , United States
| | - James M Glownia
- Linac Coherent Light Source , SLAC National Accelerator Laboratory , 2575 Sand Hill Road , Menlo Park , California 94025 , United States
| | - Danielle L Sofferman
- Program in Applied Physics , University of Michigan , 450 Church Street , Ann Arbor , Michigan 48109-1040 , United States
| | - Sanghoon Song
- Linac Coherent Light Source , SLAC National Accelerator Laboratory , 2575 Sand Hill Road , Menlo Park , California 94025 , United States
| | - Pawel M Kozlowski
- Department of Chemistry , University of Louisville , 2320 South Brook Street , Louisville , Kentucky 40292 , United States
| | - Kevin J Kubarych
- Department of Chemistry , University of Michigan , 930 N. University Ave. , Ann Arbor , Michigan 48109-1055 , United States.,Department of Biophysics , University of Michigan , 930 N. University Ave. , Ann Arbor , Michigan 48109-1055 , United States
| | - James E Penner-Hahn
- Department of Chemistry , University of Michigan , 930 N. University Ave. , Ann Arbor , Michigan 48109-1055 , United States.,Department of Biophysics , University of Michigan , 930 N. University Ave. , Ann Arbor , Michigan 48109-1055 , United States
| | - Roseanne J Sension
- Department of Chemistry , University of Michigan , 930 N. University Ave. , Ann Arbor , Michigan 48109-1055 , United States.,Department of Physics , University of Michigan , 450 Church Street , Ann Arbor , Michigan 48109-1040 , United States.,Department of Biophysics , University of Michigan , 930 N. University Ave. , Ann Arbor , Michigan 48109-1055 , United States
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18
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Khalili K, Inhester L, Arnold C, Welsch R, Andreasen JW, Santra R. Hole dynamics in a photovoltaic donor-acceptor couple revealed by simulated time-resolved X-ray absorption spectroscopy. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2019; 6:044102. [PMID: 31372369 PMCID: PMC6656576 DOI: 10.1063/1.5097653] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 06/27/2019] [Indexed: 06/01/2023]
Abstract
Theoretical and experimental methodologies that can characterize electronic and nuclear dynamics, and the coupling between the two, are needed to understand photoinduced charge transfer in molecular building blocks used in organic photovoltaics. Ongoing developments in ultrafast pump-probe techniques such as time-resolved X-ray absorption spectroscopy, using an X-ray free electron laser in combination with an ultraviolet femtosecond laser, present desirable probes of coupled electronic and nuclear dynamics. In this work, we investigate the charge transfer dynamics of a donor-acceptor pair, which is widely used as a building block in low bandgap block copolymers for organic photovoltaics. We simulate the dynamics of the benzothiadiazole-thiophene molecule upon photoionization with a vacuum ultraviolet (VUV) pulse and study the potential of probing the subsequent charge dynamics using time-resolved X-ray absorption spectroscopy. The photoinduced dynamics are calculated using on-the-fly nonadiabatic molecular dynamics simulations based on Tully's Fewest Switches Surface Hopping approach. We calculate the X-ray absorption spectrum as a function of time after ionization at the Hartree-Fock level. The changes in the time-resolved X-ray absorption spectrum at the sulfur K-edge reveal the ultrafast charge carrier dynamics in the molecule occurring on a femtosecond time scale. These theoretical findings anticipate that ultrafast time-resolved X-ray absorption spectroscopy using an X-ray probe in combination with a VUV pump offers a new approach to investigate the detailed dynamics of organic photovoltaic materials.
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Affiliation(s)
- Khadijeh Khalili
- Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | | | | | | | - Jens Wenzel Andreasen
- Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, 4000 Roskilde, Denmark
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19
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Shahsavari HR, Lalinde E, Moreno MT, Niazi M, Kazemi SH, Abedanzadeh S, Barazandeh M, Halvagar MR. Half-lantern cyclometalated Pt(ii) and Pt(iii) complexes with bridging heterocyclic thiolate ligands: synthesis, structural characterization, and electrochemical and photophysical properties. NEW J CHEM 2019. [DOI: 10.1039/c9nj00969h] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Half-lantern Pt(ii) and Pt(iii) cyclometalated binuclear complexes, bridged with various heterocyclic thiolate ligands, were synthesized and studied by electrochemical and photophysical techniques.
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Affiliation(s)
- Hamid R. Shahsavari
- Department of Chemistry
- Institute for Advanced Studies in Basic Sciences (IASBS)
- Zanjan 45137-66731
- Iran
| | - Elena Lalinde
- Departamento de Química-Centro de Síntesis Química de La Rioja, (CISQ)
- Universidad de La Rioja
- Logroño
- Spain
| | - M. Teresa Moreno
- Departamento de Química-Centro de Síntesis Química de La Rioja, (CISQ)
- Universidad de La Rioja
- Logroño
- Spain
| | - Maryam Niazi
- Department of Chemistry
- Institute for Advanced Studies in Basic Sciences (IASBS)
- Zanjan 45137-66731
- Iran
| | - Sayed Habib Kazemi
- Department of Chemistry
- Institute for Advanced Studies in Basic Sciences (IASBS)
- Zanjan 45137-66731
- Iran
| | | | - Mohammad Barazandeh
- Department of Chemistry
- Institute for Advanced Studies in Basic Sciences (IASBS)
- Zanjan 45137-66731
- Iran
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20
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Li DS, Lee YT, Xi Y, Pelivanov I, O'Donnell M, Pozzo LD. A small-angle scattering environment for in situ ultrasound studies. SOFT MATTER 2018; 14:5283-5293. [PMID: 29897086 PMCID: PMC6040585 DOI: 10.1039/c8sm01000e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Ultrasonic devices are common tools in laboratory and industrial settings to produce cavitation events for cleaning, emulsification, cell lysis and other materials applications. Effects of sonication at the macroscopic scale can be visible while effects at the molecular and nano-scales are not easily probed and, therefore, not fully understood. We present a new small angle scattering sample environment designed specifically to study structural changes occurring in various types of dispersions at the nano-scale due to ultrasonic acoustic waves. The sample environment features two face-to-face high-intensity focused ultrasound transducers coaxially aligned and normal to the neutron/X-ray beam propagation direction. A third broadband transducer is fixed beneath the scattering volume to acoustically monitor for cavitation events. By correlating acoustic data to scattering data, measured structural changes can be correlated to changes in parameters such as frequency, acoustic pressure, or cavitation pressure threshold. Several example applications of colloidal systems effectively influenced by ultrasound fields are also presented to demonstrate the capabilities of the device and to motivate future work on in situ scattering analysis of ultrasound materials processing methods.
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Affiliation(s)
- David S Li
- Department of Chemical Engineering, University of Washington, Seattle, WA, USA.
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21
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Chakraborty A, Yarnell JE, Sommer RD, Roy S, Castellano FN. Excited-State Processes of Cyclometalated Platinum(II) Charge-Transfer Dimers Bridged by Hydroxypyridines. Inorg Chem 2018; 57:1298-1310. [PMID: 29336558 DOI: 10.1021/acs.inorgchem.7b02736] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of four anti-disposed dinuclear platinum(II) complexes featuring metal-metal-to-ligand charge-transfer (MMLCT) excited states, bridged by either 2-hydroxy-6-methylpyridine or 2-hydroxy-6-phenylpyridine and cyclometalated with 7,8-benzoquinoline or 2-phenylpyridine, are presented. The 2-hydroxypyridine bridging ligands control intramolecular d8-d8 metal-metal σ interactions, affecting the frontier orbitals' electronic structure, resulting in marked changes to the ground- and excited-state properties of these complexes. Three of these molecules possess reversible one-electron oxidations in cyclic voltammetry experiments as a result of strong intramolecular metallophilic interactions. In this series of molecules, X-ray crystallography revealed Pt-Pt distances ranging between 2.815 and 2.878 Å; the former represents the shortest reported metal-metal distance for platinum(II) dimers possessing low-energy MMLCT transitions. All four molecules reported here display visible absorption bands beyond 500 nm and feature MMLCT-based red photoluminescence (PL) above 700 nm at room temperature with high PL quantum yields (up to 4%) and long excited-state lifetimes (up to 341 ns). The latter were recorded using both transient PL and transient absorption experiments that self-consistently yielded quantitatively identical excited-state lifetimes. The energy-gap law was successfully applied to this series of chromophores, documenting this behavior for the first time in molecules possessing MMLCT excited states. The combined data illustrate that entirely new classes of MMLCT chromophores can be envisioned using bridging pyridyl hydroxides in cooperation with various C^N cyclometalates to achieve photophysical properties suitable for excited-state electron- and energy-transfer chemistry.
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Affiliation(s)
- Arnab Chakraborty
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States
| | - James E Yarnell
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States
| | - Roger D Sommer
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States
| | - Subhangi Roy
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States
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22
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Leshchev D, Harlang TCB, Fredin LA, Khakhulin D, Liu Y, Biasin E, Laursen MG, Newby GE, Haldrup K, Nielsen MM, Wärnmark K, Sundström V, Persson P, Kjær KS, Wulff M. Tracking the picosecond deactivation dynamics of a photoexcited iron carbene complex by time-resolved X-ray scattering. Chem Sci 2018; 9:405-414. [PMID: 29629111 PMCID: PMC5868308 DOI: 10.1039/c7sc02815f] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 10/30/2017] [Indexed: 12/14/2022] Open
Abstract
Recent years have seen the development of new iron-centered N-heterocyclic carbene (NHC) complexes for solar energy applications. Compared to typical ligand systems, the NHC ligands provide Fe complexes with longer-lived metal-to-ligand charge transfer (MLCT) states. This increased lifetime is ascribed to strong ligand field splitting provided by the NHC ligands that raises the energy levels of the metal centered (MC) states and therefore reduces the deactivation efficiency of MLCT states. Among currently known NHC systems, [Fe(btbip)2]2+ (btbip = 2,6-bis(3-tert-butyl-imidazol-1-ylidene)pyridine) is a unique complex as it exhibits a short-lived MC state with a lifetime on the scale of a few hundreds of picoseconds. Hence, this complex allows for a detailed investigation, using 100 ps X-ray pulses from a synchrotron, of strong ligand field effects on the intermediate MC state in an NHC complex. Here, we use time-resolved wide angle X-ray scattering (TRWAXS) aided by density functional theory (DFT) to investigate the molecular structure, energetics and lifetime of the high-energy MC state in the Fe-NHC complex [Fe(btbip)2]2+ after excitation to the MLCT manifold. We identify it as a 260 ps metal-centered quintet (5MC) state, and we refine the molecular structure of the excited-state complex verifying the DFT results. Using information about the hydrodynamic state of the solvent, we also determine, for the first time, the energy of the 5MC state as 0.75 ± 0.15 eV. Our results demonstrate that due to the increased ligand field strength caused by NHC ligands, upon transition from the ground state to the 5MC state, the metal to ligand bonds extend by unusually large values: by 0.29 Å in the axial and 0.21 Å in the equatorial direction. These results imply that the transition in the photochemical properties from typical Fe complexes to novel NHC compounds is manifested not only in the destabilization of the MC states, but also in structural distortion of these states.
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Affiliation(s)
- Denis Leshchev
- European Synchrotron Radiation Facility , 71 Avenue des Martyrs , 38000 Grenoble , France .
| | - Tobias C B Harlang
- Department of Chemical Physics , Lund University , P. O. Box 12 4 , 22100 Lund , Sweden
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Lisa A Fredin
- Theoretical Chemistry Division , Lund University , P. O. Box 124 , 22100 Lund , Sweden
| | | | - Yizhu Liu
- Centre for Analysis and Synthesis , Department of Chemistry , Lund University , P. O. Box 12 4 , Lund 22100 , Sweden
| | - Elisa Biasin
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Mads G Laursen
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Gemma E Newby
- European Synchrotron Radiation Facility , 71 Avenue des Martyrs , 38000 Grenoble , France .
| | - Kristoffer Haldrup
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Martin M Nielsen
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Kenneth Wärnmark
- Centre for Analysis and Synthesis , Department of Chemistry , Lund University , P. O. Box 12 4 , Lund 22100 , Sweden
| | - Villy Sundström
- Department of Chemical Physics , Lund University , P. O. Box 12 4 , 22100 Lund , Sweden
| | - Petter Persson
- Theoretical Chemistry Division , Lund University , P. O. Box 124 , 22100 Lund , Sweden
| | - Kasper S Kjær
- Department of Chemical Physics , Lund University , P. O. Box 12 4 , 22100 Lund , Sweden
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Michael Wulff
- European Synchrotron Radiation Facility , 71 Avenue des Martyrs , 38000 Grenoble , France .
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23
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Deaton JC, Chakraborty A, Czerwieniec R, Yersin H, Castellano FN. Temperature dependence of photophysical properties of a dinuclear C^N-cyclometalated Pt(ii) complex with an intimate Pt–Pt contact. Zero-field splitting and sub-state decay rates of the lowest triplet. Phys Chem Chem Phys 2018; 20:25096-25104. [DOI: 10.1039/c8cp05213a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A dinuclear Pt(ii) complexes exhibits an unusually large zero field splitting in its metal–metal-to-ligand charge transfer triplet excited state.
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Affiliation(s)
- Joseph C. Deaton
- Department of Chemistry
- North Carolina State University
- Raleigh
- USA
| | | | - Rafal Czerwieniec
- Institut für Physikalische Chemie
- Universität Regensburg
- D-93040 Regensburg
- Germany
| | - Hartmut Yersin
- Institut für Physikalische Chemie
- Universität Regensburg
- D-93040 Regensburg
- Germany
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24
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Regulation of metal–metal interactions and chromic phenomena of multi-decker platinum complexes having π-systems. Coord Chem Rev 2018. [DOI: 10.1016/j.ccr.2017.07.016] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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25
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