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Melčák M, Šebesta F, Heyda J, Gray HB, Záliš S, Vlček A. Tryptophan to Tryptophan Hole Hopping in an Azurin Construct. J Phys Chem B 2024; 128:96-108. [PMID: 38145895 PMCID: PMC10788906 DOI: 10.1021/acs.jpcb.3c06568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/18/2023] [Accepted: 11/30/2023] [Indexed: 12/27/2023]
Abstract
Electron transfer (ET) between neutral and cationic tryptophan residues in the azurin construct [ReI(H126)(CO)3(dmp)](W124)(W122)CuI (dmp = 4,7-Me2-1,10-phenanthroline) was investigated by Born-Oppenheimer quantum-mechanics/molecular mechanics/molecular dynamics (QM/MM/MD) simulations. We focused on W124•+ ← W122 ET, which is the middle step of the photochemical hole-hopping process *ReII(CO)3(dmp•-) ← W124 ← W122 ← CuI, where sequential hopping amounts to nearly 10,000-fold acceleration over single-step tunneling (ACS Cent. Sci. 2019, 5, 192-200). In accordance with experiments, UKS-DFT QM/MM/MD simulations identified forward and reverse steps of W124•+ ↔ W122 ET equilibrium, as well as back ET ReI(CO)3(dmp•-) → W124•+ that restores *ReII(CO)3(dmp•-). Strong electronic coupling between the two indoles (≥40 meV in the crossing region) makes the productive W124•+ ← W122 ET adiabatic. Energies of the two redox states are driven to degeneracy by fluctuations of the electrostatic potential at the two indoles, mainly caused by water solvation, with contributions from the protein dynamics in the W122 vicinity. ET probability depends on the orientation of Re(CO)3(dmp) relative to W124 and its rotation diminishes the hopping yield. Comparison with hole hopping in natural systems reveals structural and dynamics factors that are important for designing efficient hole-hopping processes.
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Affiliation(s)
- Martin Melčák
- J.
Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, CZ-182 23 Prague, Czech Republic
- Department
of Physical Chemistry, University of Chemistry
and Technology Prague, Technická 5, CZ-166 28 Prague, Czech Republic
| | - Filip Šebesta
- J.
Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, CZ-182 23 Prague, Czech Republic
- Department
of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, CZ-121 16 Prague, Czech Republic
| | - Jan Heyda
- J.
Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, CZ-182 23 Prague, Czech Republic
- Department
of Physical Chemistry, University of Chemistry
and Technology Prague, Technická 5, CZ-166 28 Prague, Czech Republic
| | - Harry B. Gray
- Beckman
Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Stanislav Záliš
- J.
Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Antonín Vlček
- J.
Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, CZ-182 23 Prague, Czech Republic
- Department
of Chemistry, Queen Mary University of London, London E1 4NS, U.K.
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Šrut A, Mai S, Sazanovich IV, Heyda J, Vlček A, González L, Záliš S. Nonadiabatic excited-state dynamics of ReCl(CO) 3(bpy) in two different solvents. Phys Chem Chem Phys 2022; 24:25864-25877. [PMID: 36279148 DOI: 10.1039/d2cp02981b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We present a study of excited-states relaxation of the complex ReCl(CO)3(bpy) (bpy = 2,2-bipyridine) using a nonadiabatic TD-DFT dynamics on spin-mixed potential energy surfaces in explicit acetonitrile (ACN) and dimethylsulfoxide (DMSO) solutions up to 800 fs. ReCl(CO)3(bpy) belongs to a group of important photosensitizers which show ultrafast biexponential subpicosecond fluorescence decay kinetics. The choice of solvents was motivated by the different excited-state relaxation dynamics observed in subpicosecond time-resolved IR (TRIR) experiments. Simulations of intersystem crossing (ISC) showed the development of spin-mixed states in both solvents. Transformation of time-dependent populations of spin-mixed states enabled to monitor the temporal evolution of individual singlet and triplet states, fitting of bi-exponential decay kinetics, and simulating the time-resolved fluorescence spectra that show only minor differences between the two solvents. Analysis of structural relaxation and solvent reorganization employing time-resolved proximal distribution functions pointed to the factors influencing the fluorescence decay time constants. Nonadiabatic dynamics simulations of time-evolution of electronic, molecular, and solvent structures emerge as a powerful technique to interpret time-resolved spectroscopic data and ultrafast photochemical reactivity.
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Affiliation(s)
- Adam Šrut
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, 182 23 Prague, Czech Republic.
- Department of Physical Chemistry, University of Chemistry and Technology, Prague, 166 28 Prague, Czech Republic.
| | - Sebastian Mai
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, 1090 Vienna, Austria.
| | - Igor V Sazanovich
- Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire, OX11 0QX, UK
| | - Jan Heyda
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, 182 23 Prague, Czech Republic.
- Department of Physical Chemistry, University of Chemistry and Technology, Prague, 166 28 Prague, Czech Republic.
| | - Antonín Vlček
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, 182 23 Prague, Czech Republic.
- Department of Chemistry, Queen Mary University of London, London, E1 4NS, UK
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, 1090 Vienna, Austria.
| | - Stanislav Záliš
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, 182 23 Prague, Czech Republic.
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Brink A, Jacobs FJF, Helliwell JR. Trends in coordination of rhenium organometallic complexes in the Protein Data Bank. IUCRJ 2022; 9:180-193. [PMID: 35371500 PMCID: PMC8895017 DOI: 10.1107/s2052252522000665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
Radiopharmaceutical development has similar overall characteristics to any biomedical drug development requiring a compound's stability, aqueous solubility and selectivity to a specific disease site. However, organometallic complexes containing 188/186Re or 99mTc involve a d-block transition-metal radioactive isotope and therefore bring additional factors such as metal oxidation states, isotope purity and half life into play. This topical review is focused on the development of radiopharmaceuticals containing the radioisotopes of rhenium and technetium and, therefore, on the occurrence of these organometallic complexes in protein structures in the Worldwide Protein Data Bank (wwPDB). The purpose of incorporating the group 7 transition metals of rhenium/technetium in the protein and the reasons for study by protein crystallography are described, as certain PDB studies were not aimed at drug development. Technetium is used as a medical diagnostic agent and involves the 99mTc isotope which decays to release gamma radiation, thereby employed for its use in gamma imaging. Due to the periodic relationship among group 7 transition metals, the coordination chemistry of rhenium is similar (but not identical) to that of technetium. The types of reactions the potential model radiopharmaceutical would prefer to partake in, and by extension knowing which proteins and biomolecules the compound would react with in vivo, are needed. Crystallography studies, both small molecule and macromolecular, are a key aspect in understanding chemical coordination. Analyses of bonding modes, coordination to particular residues and crystallization conditions are presented. In our Forward look as a concluding summary of this topical review, the question we ask is: what is the best way for this field to progress?
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Affiliation(s)
- Alice Brink
- Chemistry Department, University of the Free State, Nelson Mandela Drive, Bloemfontein, South Africa
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, United Kingdom
| | - Francois J. F. Jacobs
- Chemistry Department, University of the Free State, Nelson Mandela Drive, Bloemfontein, South Africa
| | - John R. Helliwell
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, United Kingdom
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Pospíšil P, Cwiklik L, Sýkora J, Hof M, Greetham GM, Towrie M, Vlček A. Solvent-Dependent Excited-State Evolution of Prodan Dyes. J Phys Chem B 2021; 125:13858-13867. [PMID: 34914398 DOI: 10.1021/acs.jpcb.1c09030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Excited-state character and dynamics of two 6-(dimethylamino)-2-acylnaphthalene dyes (Prodan and Badan-SCH2CH2OH) were studied by picosecond time-resolved IR spectroscopy (TRIR) in solvents of different polarity and relaxation times: hexane, CD3OD, and glycerol-d8. In all these solvents, near-UV excitation initially produced the same S1(ππ*) excited state characterized by a broad TRIR signal. A very fast decay (3, ∼100 ps) followed in hexane, whereas conversion to a distinct IR spectrum with a ν(C═O) band downshifted by 76 cm-1 occurred in polar/H-bonding solvents, slowing down on going from CD3OD (1, 23 ps) to glycerol-d8 (5.5, 51, 330 ps). The final relaxed excited state was assigned as planar Me2N → C═O intramolecular charge transfer S1(ICT) by comparing experimental and TDDFT-calculated spectra. TRIR conversion kinetics are comparable to those of early stages of multiexponential fluorescence decay and dynamic fluorescence red-shift. This work presents a strong evidence that Prodan-type dyes undergo solvation-driven charge separation in their S1 state, which is responsible for the dynamic fluorescence Stokes shift observed in polar/H-bonding solvents. The time evolution of the optically prepared S1(ππ*) state to the S1(ICT) final state reflects environment relaxation and solvation dynamics. This finding rationalizes the widespread use of Prodan-type dyes as probes of environment dynamics and polarity.
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Affiliation(s)
- Petr Pospíšil
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, CZ-18223 Prague, Czech Republic
| | - Lukasz Cwiklik
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, CZ-18223 Prague, Czech Republic
| | - Jan Sýkora
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, CZ-18223 Prague, Czech Republic
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, CZ-18223 Prague, Czech Republic
| | - Gregory M Greetham
- Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Michael Towrie
- Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Antonín Vlček
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, CZ-18223 Prague, Czech Republic.,Department of Chemistry, Queen Mary University of London, E1 4NS London, United Kingdom
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Abstract
Hole hopping through tryptophan/tyrosine chains enables rapid unidirectional charge transport over long distances. We have elucidated structural and dynamical factors controlling hopping speed and efficiency in two modified azurin constructs that include a rhenium(I) sensitizer, Re(His)(CO)3(dmp)+, and one or two tryptophans (W1, W2). Experimental kinetics investigations showed that the two closely spaced (3 to 4 Å) intervening tryptophans dramatically accelerated long-range electron transfer (ET) from CuI to the photoexcited sensitizer. In our theoretical work, we found that time-dependent density-functional theory (TDDFT) quantum mechanics/molecular mechanics/molecular dynamics (QM/MM/MD) trajectories of low-lying triplet excited states of ReI(His)(CO)3(dmp)+-W1(-W2) exhibited crossings between sensitizer-localized (*Re) and charge-separated [ReI(His)(CO)3(dmp•-)/(W1 •+ or W2 •+)] (CS1 or CS2) states. Our analysis revealed that the distances, angles, and mutual orientations of ET-active cofactors fluctuate in a relatively narrow range in which the cofactors are strongly coupled, enabling adiabatic ET. Water-dominated electrostatic field fluctuations bring *Re and CS1 states to a crossing where *Re(CO)3(dmp)+←W1 ET occurs, and CS1 becomes the lowest triplet state. ET is promoted by solvation dynamics around *Re(CO)3(dmp)+(W1); and CS1 is stabilized by Re(dmp•-)/W1 •+ electron/hole interaction and enhanced W1 •+ solvation. The second hop, W1 •+←W2, is facilitated by water fluctuations near the W1/W2 unit, taking place when the electrostatic potential at W2 drops well below that at W1 •+ Insufficient solvation and reorganization around W2 make W1 •+←W2 ET endergonic, shifting the equilibrium toward W1 •+ and decreasing the charge-separation yield. We suggest that multiscale TDDFT/MM/MD is a suitable technique to model the simultaneous evolution of photogenerated excited-state manifolds.
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Mai S, Menger MFSJ, Marazzi M, Stolba DL, Monari A, González L. Competing ultrafast photoinduced electron transfer and intersystem crossing of [Re(CO) 3 (Dmp)(His124)(Trp122)] + in Pseudomonas aeruginosa azurin: a nonadiabatic dynamics study. Theor Chem Acc 2020; 139:65. [PMID: 32214889 PMCID: PMC7078154 DOI: 10.1007/s00214-020-2555-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 01/20/2020] [Indexed: 12/28/2022]
Abstract
We present a computational study of sub-picosecond nonadiabatic dynamics in a rhenium complex coupled electronically to a tryptophan (Trp) side chain of Pseudomonas aeruginosa azurin, a prototypical protein used in the study of electron transfer in proteins. To gain a comprehensive understanding of the photoinduced processes in this system, we have carried out vertical excitation calculations at the TDDFT level of theory as well as nonadiabatic dynamics simulations using the surface hopping including arbitrary couplings (SHARC) method coupled to potential energy surfaces represented with a linear vibronic coupling model. The results show that the initial photoexcitation populates both singlet metal-to-ligand charge transfer (MLCT) and singlet charge-separated (CS) states, where in the latter an electron was transferred from the Trp amino acid to the complex. Subsequently, a complex mechanism of simultaneous intersystem crossing and electron transfer leads to the sub-picosecond population of triplet MLCT and triplet CS states. These results confirm the assignment of the sub-ps time constants of previous experimental studies and constitute the first computational evidence for the ultrafast formation of the charge-separated states in Re-sensitized azurin.
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Affiliation(s)
- Sebastian Mai
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna, Austria
- Present Address: Photonics Institute, Vienna University of Technology, Gußhausstr. 27–29, 1040 Vienna, Austria
| | - Maximilian F. S. J. Menger
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna, Austria
- Present Address: Zernike Institute for Advanced Materials, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Marco Marazzi
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Universidad de Alcalá, Ctra. Madrid-Barcelona Km. 33,600, 28871 Alcalá de Henares, Madrid Spain
- Chemical Research Institute “Andrés M. del Río” (IQAR), Universidad de Alcalá, 28871 Alcalá de Henares, Madrid Spain
| | - Dario L. Stolba
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna, Austria
| | - Antonio Monari
- Université de Lorraine and CNRS, LPTC UMR, 7019 Nancy, France
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna, Austria
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Pospíšil P, Sýkora J, Takematsu K, Hof M, Gray HB, Vlček A. Light-Induced Nanosecond Relaxation Dynamics of Rhenium-Labeled Pseudomonas aeruginosa Azurins. J Phys Chem B 2020; 124:788-797. [PMID: 31935093 DOI: 10.1021/acs.jpcb.9b10802] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Time-resolved phosphorescence spectra of Re(CO)3(dmp)+ and Re(CO)3(phen)+ chromophores (dmp = 4,7-dimethyl-1,10-phenanthroline, phen = 1,10-phenanthroline) bound to surface histidines (H83, H124, and H126) of Pseudomonas aeruginosa azurin mutants exhibit dynamic band maxima shifts to lower wavenumbers following 3-exponential kinetics with 1-5 and 20-100 ns major phases and a 1.1-2.5 μs minor (5-16%) phase. Observation of slow relaxation components was made possible by using an organometallic Re chromophore as a probe whose long phosphorescence lifetime extends the observation window up to ∼3 μs. Integrated emission-band areas also decay with 2- or 3-exponential kinetics; the faster decay phase(s) is relaxation-related, whereas the slowest one [360-680 ns (dmp); 90-140 ns (phen)] arises mainly from population decay. As a result of shifting bands, the emission intensity decay kinetics depend on the detection wavelength. Detailed kinetics analyses and comparisons with band-shift dynamics are needed to disentangle relaxation and population decay kinetics if they occur on comparable timescales. The dynamic phosphorescence Stokes shift in Re-azurins is caused by relaxation motions of the solvent, the protein, and solvated amino acid side chains at the Re binding site in response to chromophore electronic excitation. Comparing relaxation and decay kinetics of Re(dmp)124K122CuII and Re(dmp)124W122CuII suggests that electron transfer (ET) and relaxation motions in the W122 mutant are coupled. It follows that nanosecond and faster photo-induced ET steps in azurins (and likely other redox proteins) occur from unrelaxed systems; importantly, these reactions can be driven (or hindered) by structural and solvational dynamics.
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Affiliation(s)
- Petr Pospíšil
- J. Heyrovský Institute of Physical Chemistry , Czech Academy of Sciences , Dolejškova 3 , CZ-182 23 Prague , Czech Republic
| | - Jan Sýkora
- J. Heyrovský Institute of Physical Chemistry , Czech Academy of Sciences , Dolejškova 3 , CZ-182 23 Prague , Czech Republic
| | - Kana Takematsu
- Department of Chemistry , Bowdoin College , Brunswick , Maine 04011 , United States
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry , Czech Academy of Sciences , Dolejškova 3 , CZ-182 23 Prague , Czech Republic
| | - Harry B Gray
- Beckman Institute , California Institute of Technology , Pasadena , California 91125 , United States
| | - Antonín Vlček
- J. Heyrovský Institute of Physical Chemistry , Czech Academy of Sciences , Dolejškova 3 , CZ-182 23 Prague , Czech Republic.,School of Biological and Chemical Sciences , Queen Mary University of London , Mile End Road , E1 4NS London , U.K
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Relaxation dynamics of [Re(CO) 2(bpy){P(OEt) 3} 2](PF 6) in TEOA solvent measured by time-resolved attenuated total reflection terahertz spectroscopy. Sci Rep 2019; 9:11772. [PMID: 31409913 PMCID: PMC6692373 DOI: 10.1038/s41598-019-48191-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 07/30/2019] [Indexed: 12/02/2022] Open
Abstract
To reveal highly efficient photocatalytic properties of an artificial photosynthesis material [Re(CO)2(bpy){P(OEt)3}2](PF6), we have directly observed the photo-induced relaxation dynamics and reductive quenching process of the photo-excited state on a photosynthesis material in Triethanolamine (TEOA) solvent as an electron donor by time-resolved attenuated total reflection spectroscopy in the terahertz (THz) region. The spectrum of the complex in TEOA has an intermolecular vibrational mode between the complex and TEOA molecules, which reflects the precursor of the reductive quenching process. The intermolecular vibrational mode has three-step relaxation process in a picosecond timescale after photo-excitation, where firstly the triplet metal-to-ligand charge transfer excited state is vibrationally cooled down, secondly the distance between Re and TEOA is reduced by the rotation of TEOA molecules due to dipole-dipole interaction accelerated by heat transfer, and finally electrons transfer from TEOA to Re. These observations provide us the detailed information of the electron transfer process of photocatalytic properties of [Re(CO)2(bpy){P(OEt)3}2](PF6) in TEOA solvent.
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Computational Assessment of MLCT versus MC Stabilities in First‐to‐Third‐Row d
6
Pseudo‐Octahedral Transition Metal Complexes. J Comput Chem 2019; 40:2377-2390. [DOI: 10.1002/jcc.26014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/11/2019] [Accepted: 06/11/2019] [Indexed: 11/07/2022]
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Takematsu K, Pospíšil P, Pižl M, Towrie M, Heyda J, Záliš S, Kaiser JT, Winkler JR, Gray HB, Vlček A. Hole Hopping Across a Protein-Protein Interface. J Phys Chem B 2019; 123:1578-1591. [PMID: 30673250 PMCID: PMC6384139 DOI: 10.1021/acs.jpcb.8b11982] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have investigated photoinduced hole hopping in a Pseudomonas aeruginosa azurin mutant Re126WWCuI, where two adjacent tryptophan residues (W124 and W122) are inserted between the CuI center and a Re photosensitizer coordinated to a H126 imidazole (Re = ReI(H126)(CO)3(dmp)+, dmp = 4,7-dimethyl-1,10-phenanthroline). Optical excitation of this mutant in aqueous media (≤40 μM) triggers 70 ns electron transport over 23 Å, yielding a long-lived (120 μs) ReI(H126)(CO)3(dmp•-)WWCuII product. The Re126FWCuI mutant (F124, W122) is not redox-active under these conditions. Upon increasing the concentration to 0.2-2 mM, {Re126WWCuI}2 and {Re126FWCuI}2 are formed with the dmp ligand of the Re photooxidant of one molecule in close contact (3.8 Å) with the W122' indole on the neighboring chain. In addition, {Re126WWCuI}2 contains an interfacial tryptophan quadruplex of four indoles (3.3-3.7 Å apart). In both mutants, dimerization opens an intermolecular W122' → //*Re ET channel (// denotes the protein interface, *Re is the optically excited sensitizer). Excited-state relaxation and ET occur together in two steps (time constants of ∼600 ps and ∼8 ns) that lead to a charge-separated state containing a Re(H126)(CO)3(dmp•-)//(W122•+)' unit; then (CuI)' is oxidized intramolecularly (60-90 ns) by (W122•+)', forming ReI(H126)(CO)3(dmp•-)WWCuI//(CuII)'. The photocycle is closed by ∼1.6 μs ReI(H126)(CO)3(dmp•-) → //(CuII)' back ET that occurs over 12 Å, in contrast to the 23 Å, 120 μs step in Re126WWCuI. Importantly, dimerization makes Re126FWCuI photoreactive and, as in the case of {Re126WWCuI}2, channels the photoproduced "hole" to the molecule that was not initially photoexcited, thereby shortening the lifetime of ReI(H126)(CO)3(dmp•-)//CuII. Although two adjacent W124 and W122 indoles dramatically enhance CuI → *Re intramolecular multistep ET, the tryptophan quadruplex in {Re126WWCuI}2 does not accelerate intermolecular electron transport; instead, it acts as a hole storage and crossover unit between inter- and intramolecular ET pathways. Irradiation of {Re126WWCuII}2 or {Re126FWCuII}2 also triggers intermolecular W122' → //*Re ET, and the Re(H126)(CO)3(dmp•-)//(W122•+)' charge-separated state decays to the ground state by ∼50 ns ReI(H126)(CO)3(dmp•-)+ → //(W122•+)' intermolecular charge recombination. Our findings shed light on the factors that control interfacial hole/electron hopping in protein complexes and on the role of aromatic amino acids in accelerating long-range electron transport.
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Affiliation(s)
- Kana Takematsu
- Department of Chemistry, Bowdoin College, Brunswick, ME 04011, USA
| | - Petr Pospíšil
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Martin Pižl
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
- University of Chemistry and Technology, Prague, Technická 5, CZ-166 28 Prague, Czech Republic
| | - Michael Towrie
- Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire, OX11 0FA, UK
| | - Jan Heyda
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
- University of Chemistry and Technology, Prague, Technická 5, CZ-166 28 Prague, Czech Republic
| | - Stanislav Záliš
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Jens T. Kaiser
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Jay R. Winkler
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Harry B. Gray
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Antonín Vlček
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
- Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, United Kingdom
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Takematsu K, Williamson HR, Nikolovski P, Kaiser JT, Sheng Y, Pospíšil P, Towrie M, Heyda J, Hollas D, Záliš S, Gray HB, Vlček A, Winkler JR. Two Tryptophans Are Better Than One in Accelerating Electron Flow through a Protein. ACS CENTRAL SCIENCE 2019; 5:192-200. [PMID: 30693338 PMCID: PMC6346393 DOI: 10.1021/acscentsci.8b00882] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Indexed: 06/09/2023]
Abstract
We have constructed and structurally characterized a Pseudomonas aeruginosa azurin mutant Re126WWCuI , where two adjacent tryptophan residues (W124 and W122, indole separation 3.6-4.1 Å) are inserted between the CuI center and a Re photosensitizer coordinated to the imidazole of H126 (ReI(H126)(CO)3(4,7-dimethyl-1,10-phenanthroline)+). CuI oxidation by the photoexcited Re label (*Re) 22.9 Å away proceeds with a ∼70 ns time constant, similar to that of a single-tryptophan mutant (∼40 ns) with a 19.4 Å Re-Cu distance. Time-resolved spectroscopy (luminescence, visible and IR absorption) revealed two rapid reversible electron transfer steps, W124 → *Re (400-475 ps, K 1 ≅ 3.5-4) and W122 → W124•+ (7-9 ns, K 2 ≅ 0.55-0.75), followed by a rate-determining (70-90 ns) CuI oxidation by W122•+ ca. 11 Å away. The photocycle is completed by 120 μs recombination. No photochemical CuI oxidation was observed in Re126FWCuI , whereas in Re126WFCuI , the photocycle is restricted to the ReH126W124 unit and CuI remains isolated. QM/MM/MD simulations of Re126WWCuI indicate that indole solvation changes through the hopping process and W124 → *Re electron transfer is accompanied by water fluctuations that tighten W124 solvation. Our finding that multistep tunneling (hopping) confers a ∼9000-fold advantage over single-step tunneling in the double-tryptophan protein supports the proposal that hole-hopping through tryptophan/tyrosine chains protects enzymes from oxidative damage.
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Affiliation(s)
- Kana Takematsu
- Department
of Chemistry, Bowdoin College, Brunswick, Maine 04011, United States
| | - Heather R Williamson
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 70125, United States
| | - Pavle Nikolovski
- Beckman
Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Jens T. Kaiser
- Beckman
Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Yuling Sheng
- Beckman
Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Petr Pospíšil
- J.
Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Michael Towrie
- Central
Laser Facility, Research Complex at Harwell, Science and Technology
Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot,
Oxfordshire, OX11 0FA, U.K.
| | - Jan Heyda
- J.
Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
- Department
of Physical Chemistry, University of Chemistry
and Technology, Prague, Technická 5, CZ-166
28 Prague, Czech Republic
| | - Daniel Hollas
- Department
of Physical Chemistry, University of Chemistry
and Technology, Prague, Technická 5, CZ-166
28 Prague, Czech Republic
| | - Stanislav Záliš
- J.
Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Harry B. Gray
- Beckman
Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Antonín Vlček
- J.
Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
- School
of Biological and Chemical Sciences, Queen
Mary University of London, Mile End Road, London E1 4NS, United Kingdom
| | - Jay R. Winkler
- Beckman
Institute, California Institute of Technology, Pasadena, California 91125, United States
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12
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Marazzi M, Gattuso H, Fumanal M, Daniel C, Monari A. Charge-Transfer versus Charge-Separated Triplet Excited States of [Re I (dmp)(CO) 3 (His124)(Trp122)] + in Water and in Modified Pseudomonas aeruginosa Azurin Protein. Chemistry 2019; 25:2519-2526. [PMID: 30379366 DOI: 10.1002/chem.201803685] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 10/17/2018] [Indexed: 12/20/2022]
Abstract
A computational investigation of the triplet excited states of a rhenium complex electronically coupled with a tryptophan side chain and bound to an azurin protein is presented. In particular, by using high-level molecular modeling, evidence is provided for how the electronic properties of the excited-state manifolds strongly depend on coupling with the environment. Indeed, only upon explicitly taking into account the protein environment can two stable triplet states of metal-to-ligand charge transfer or charge-separated nature be recovered. In addition, it is also demonstrated how the rhenium complex plus tryptophan system in an aqueous environment experiences too much flexibility, which prevents the two chromophores from being electronically coupled. This occurrence disables the formation of a charge-separated state. The successful strategy requires a multiscale approach of combining molecular dynamics and quantum chemistry. In this context, the strategy used to parameterize the force fields for the electronic triplet states of the metal complex is also presented.
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Affiliation(s)
- Marco Marazzi
- Université de Lorraine, CNRS, LPCT UMR 7019, Boulevard des Aiguillettes, Vandoeuvre-lès-Nancy, 54000, Nancy, France.,Departamento de Química, Centro de Investigacíon en Síntesis Química (CISQ), Universidad de La Rioja, Madre de Dios, 53, 26006, Logroño, Spain
| | - Hugo Gattuso
- Université de Lorraine, CNRS, LPCT UMR 7019, Boulevard des Aiguillettes, Vandoeuvre-lès-Nancy, 54000, Nancy, France
| | - Maria Fumanal
- Laboratoire de Chimie Quantique, Institut de Chimie Strasbourg, UMR-7177, CNRS/Université de Strasbourg, 1 Rue Blaise Pascal BP 296/R8, 67008, Strasbourg, France
| | - Chantal Daniel
- Laboratoire de Chimie Quantique, Institut de Chimie Strasbourg, UMR-7177, CNRS/Université de Strasbourg, 1 Rue Blaise Pascal BP 296/R8, 67008, Strasbourg, France
| | - Antonio Monari
- Université de Lorraine, CNRS, LPCT UMR 7019, Boulevard des Aiguillettes, Vandoeuvre-lès-Nancy, 54000, Nancy, France
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13
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Brown AM, McCusker CE, Carey MC, Blanco-Rodríguez AM, Towrie M, Clark IP, Vlček A, McCusker JK. Vibrational Relaxation and Redistribution Dynamics in Ruthenium(II) Polypyridyl-Based Charge-Transfer Excited States: A Combined Ultrafast Electronic and Infrared Absorption Study. J Phys Chem A 2018; 122:7941-7953. [DOI: 10.1021/acs.jpca.8b06197] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Allison M. Brown
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Catherine E. McCusker
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Monica C. Carey
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Ana Maria Blanco-Rodríguez
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
| | - Michael Towrie
- Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Ian P. Clark
- Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Antonín Vlček
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
- J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejskova 3, CZ-182 23 Prague, Czech Republic
| | - James K. McCusker
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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14
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Fumanal M, Gindensperger E, Daniel C. Ultrafast Intersystem Crossing vs Internal Conversion in α-Diimine Transition Metal Complexes: Quantum Evidence. J Phys Chem Lett 2018; 9:5189-5195. [PMID: 30145893 DOI: 10.1021/acs.jpclett.8b02319] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Whereas third row transition metal carbonyl α-diimine complexes display luminescent properties and possess low-lying triplet metal-to-ligand charge transfer (MLCT) states efficiently accessible by a spin-vibronic mechanism, first row analogues hold low-lying metal-centered (MC) excited states that could quench these properties. Upon visible irradiation, different functions are potentially stimulated, namely, luminescence, electron transfer, or photoinduced CO release, the branching ratio of which is governed by the energetics, the character, and the early time dynamics of the photoactive excited states. Simulations of ultrafast nonadiabatic quantum dynamics, including spin-vibronic effects, of [M(imidazole)(CO)3(phenanthroline)]+ (M = Mn, Re) highlight the role of the metal atom. An ultrafast intersystem crossing process, driven by spin-orbit coupling, populates the low-lying triplet states of [Re(imidazole)(CO)3(phen)]+ within the first tens of fs. In contrast, efficient internal conversion between the two lowest 1MLCT states of [Mn(imidazole)(CO)3(phen)]+ is mediated within 50 fs by vibronic coupling with upper MC and MLCT states.
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Affiliation(s)
- Maria Fumanal
- Laboratoire de Chimie Quantique, Institut de Chimie Strasbourg , UMR7177 CNRS/Université de Strasbourg , 1 Rue Blaise Pascal BP296/R8 , F-67008 Strasbourg , France
| | - Etienne Gindensperger
- Laboratoire de Chimie Quantique, Institut de Chimie Strasbourg , UMR7177 CNRS/Université de Strasbourg , 1 Rue Blaise Pascal BP296/R8 , F-67008 Strasbourg , France
| | - Chantal Daniel
- Laboratoire de Chimie Quantique, Institut de Chimie Strasbourg , UMR7177 CNRS/Université de Strasbourg , 1 Rue Blaise Pascal BP296/R8 , F-67008 Strasbourg , France
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15
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Konkankit CC, Marker SC, Knopf KM, Wilson JJ. Anticancer activity of complexes of the third row transition metals, rhenium, osmium, and iridium. Dalton Trans 2018; 47:9934-9974. [DOI: 10.1039/c8dt01858h] [Citation(s) in RCA: 153] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A summary of recent developments on the anticancer activity of complexes of rhenium, osmium, and iridium is described.
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Affiliation(s)
| | - Sierra C. Marker
- Department of Chemistry and Chemical Biology
- Cornell University
- Ithaca
- USA
| | - Kevin M. Knopf
- Department of Chemistry and Chemical Biology
- Cornell University
- Ithaca
- USA
| | - Justin J. Wilson
- Department of Chemistry and Chemical Biology
- Cornell University
- Ithaca
- USA
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16
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Pižl M, Hunter BM, Greetham GM, Towrie M, Záliš S, Gray HB, Vlček A. Ultrafast Wiggling and Jiggling: Ir 2(1,8-diisocyanomenthane) 42. J Phys Chem A 2017; 121:9275-9283. [PMID: 29131954 DOI: 10.1021/acs.jpca.7b10215] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Binuclear complexes of d8 metals (PtII, IrI, RhI,) exhibit diverse photonic behavior, including dual emission from relatively long-lived singlet and triplet excited states, as well as photochemical energy, electron, and atom transfer. Time-resolved optical spectroscopic and X-ray studies have revealed the behavior of the dimetallic core, confirming that M-M bonding is strengthened upon dσ* → pσ excitation. We report the bridging ligand dynamics of Ir2(1,8-diisocyanomenthane)42+ (Ir(dimen)), investigated by fs-ns time-resolved IR spectroscopy (TRIR) in the region of C≡N stretching vibrations, ν(C≡N), 2000-2300 cm-1. The ν(C≡N) IR band of the singlet and triplet dσ*pσ excited states is shifted by -22 and -16 cm-1 relative to the ground state due to delocalization of the pσ LUMO over the bridging ligands. Ultrafast relaxation dynamics of the 1dσ*pσ state depend on the initially excited Franck-Condon molecular geometry, whereby the same relaxed singlet excited state is populated by two different pathways depending on the starting point at the excited-state potential energy surface. Exciting the long/eclipsed isomer triggers two-stage structural relaxation: 0.5 ps large-scale Ir-Ir contraction and 5 ps Ir-Ir contraction/intramolecular rotation. Exciting the short/twisted isomer induces a ∼5 ps bond shortening combined with vibrational cooling. Intersystem crossing (70 ps) follows, populating a 3dσ*pσ state that lives for hundreds of nanoseconds. During the first 2 ps, the ν(C≡N) IR bandwidth oscillates with the frequency of the ν(Ir-Ir) wave packet, ca. 80 cm-1, indicating that the dephasing time of the high-frequency (16 fs)-1 C≡N stretch responds to much slower (∼400 fs)-1 Ir-Ir coherent oscillations. We conclude that the bonding and dynamics of bridging di-isocyanide ligands are coupled to the dynamics of the metal-metal unit and that the coherent Ir-Ir motion induced by ultrafast excitation drives vibrational dephasing processes over the entire binuclear cation.
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Affiliation(s)
- Martin Pižl
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic , Dolejškova 3, CZ-182 23 Prague, Czech Republic.,Department of Inorganic Chemistry, University of Chemistry and Technology, Prague , Technická 5, CZ-166 28 Prague, Czech Republic
| | - Bryan M Hunter
- Beckman Institute, California Institute of Technology , Pasadena, California 91125, United States
| | - Gregory M Greetham
- Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton Laboratory , Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Michael Towrie
- Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton Laboratory , Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Stanislav Záliš
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic , Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Harry B Gray
- Beckman Institute, California Institute of Technology , Pasadena, California 91125, United States
| | - Antonín Vlček
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic , Dolejškova 3, CZ-182 23 Prague, Czech Republic.,School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London E1 4NS, United Kingdom
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17
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18
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Abstract
Biological electron transfer reactions between metal cofactors are critical to many essential processes within the cell. Duplex DNA is, moreover, capable of mediating the transport of charge through its π-stacked nitrogenous bases. Increasingly, [4Fe4S] clusters, generally redox-active cofactors, have been found to be associated with enzymes involved in DNA processing. DNA-binding enzymes containing [4Fe4S] clusters can thus utilize DNA charge transport (DNA CT) for redox signaling to coordinate reactions over long molecular distances. In particular, DNA CT signaling may represent the first step in the search for DNA lesions by proteins containing [4Fe4S] clusters that are involved in DNA repair. Here we describe research carried out to examine the chemical characteristics and biological consequences of DNA CT. We are finding that DNA CT among metalloproteins represents powerful chemistry for redox signaling at long range within the cell.
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Affiliation(s)
- Elizabeth O’Brien
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena CA 91125
| | - Rebekah M.B. Silva
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena CA 91125
| | - Jacqueline K. Barton
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena CA 91125
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19
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Fumanal M, Daniel C. Electronic and Photophysical Properties of [Re (L)(CO)3(phen)]+ and [Ru(L)2(bpy)2]2+ (L = imidazole), Building Units for Long-Range Electron Transfer in Modified Blue Copper Proteins. J Phys Chem A 2016; 120:6934-43. [DOI: 10.1021/acs.jpca.6b06438] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Maria Fumanal
- Laboratoire
de Chimie Quantique, Institut de Chimie Strasbourg, UMR-7177
CNRS/Université de Strasbourg 1
Rue Blaise Pascal BP 296/R8, F-67008 Strasbourg, France
| | - Chantal Daniel
- Laboratoire
de Chimie Quantique, Institut de Chimie Strasbourg, UMR-7177
CNRS/Université de Strasbourg 1
Rue Blaise Pascal BP 296/R8, F-67008 Strasbourg, France
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20
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Fumanal M, Daniel C. Description of excited states in [Re(Imidazole)(CO)3
(Phen)]+
including solvent and spin-orbit coupling effects: Density functional theory versus multiconfigurational wavefunction approach. J Comput Chem 2016; 37:2454-66. [DOI: 10.1002/jcc.24469] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Revised: 07/22/2016] [Accepted: 07/25/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Maria Fumanal
- Laboratoire De Chimie Quantique, Institut De Chimie Strasbourg, UMR7177 CNRS/Université De Strasbourg; 1 Rue Blaise Pascal BP296/R8 Strasbourg F-67008 France
| | - Chantal Daniel
- Laboratoire De Chimie Quantique, Institut De Chimie Strasbourg, UMR7177 CNRS/Université De Strasbourg; 1 Rue Blaise Pascal BP296/R8 Strasbourg F-67008 France
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21
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Eng J, Daniel C. Structural Properties and UV–Visible Absorption Spectroscopy of Retinal-pyridyl-CN Re(I) Carbonyl Bipyridine Complex: A Theoretical Study. J Phys Chem A 2015; 119:10645-53. [DOI: 10.1021/acs.jpca.5b08047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Julien Eng
- Laboratoire de Chimie Quantique,
Institut de Chimie Strasbourg, UMR-7177 CNRS/Université de Strasbourg 1 Rue Blaise Pascal BP 296/R8, F-67008 STRASBOURG, France
| | - Chantal Daniel
- Laboratoire de Chimie Quantique,
Institut de Chimie Strasbourg, UMR-7177 CNRS/Université de Strasbourg 1 Rue Blaise Pascal BP 296/R8, F-67008 STRASBOURG, France
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22
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Kvapilová H, Vlček A, Barone V, Biczysko M, Záliš S. Anharmonicity Effects in IR Spectra of [Re(X)(CO)3(α-diimine)] (α-diimine = 2,2′-bipyridine or pyridylimidazo[1,5-a]pyridine; X = Cl or NCS) Complexes in Ground and Excited Electronic States. J Phys Chem A 2015; 119:10137-46. [DOI: 10.1021/acs.jpca.5b07585] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hana Kvapilová
- J.
Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague 8, Czech Republic
- Department
of Inorganic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic
| | - Antonín Vlček
- J.
Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague 8, Czech Republic
- Queen
Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, United Kingdom
| | - Vincenzo Barone
- Scuola
Normale Superiore, Piazza dei Cavalieri, 7 I-56126 Pisa, Italy
| | - Malgorzata Biczysko
- Physics
Department, and International Centre for Quantum and Molecular Structures, Shanghai University, 99 Shangda Road, Shanghai, 200444 China
| | - Stanislav Záliš
- J.
Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague 8, Czech Republic
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23
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Kvapilová H, Sattler W, Sattler A, Sazanovich IV, Clark IP, Towrie M, Gray HB, Záliš S, Vlček A. Electronic Excited States of Tungsten(0) Arylisocyanides. Inorg Chem 2015; 54:8518-28. [PMID: 26267759 DOI: 10.1021/acs.inorgchem.5b01203] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
W(CNAryl)6 complexes containing 2,6-diisopropylphenyl isocyanide (CNdipp) are powerful photoreductants with strongly emissive long-lived excited states. These properties are enhanced upon appending another aryl ring, e.g., W(CNdippPh(OMe2))6; CNdippPh(OMe2) = 4-(3,5-dimethoxyphenyl)-2,6-diisopropylphenylisocyanide (Sattler et al. J. Am. Chem. Soc. 2015, 137, 1198-1205). Electronic transitions and low-lying excited states of these complexes were investigated by time-dependent density functional theory (TDDFT); the lowest triplet state was characterized by time-resolved infrared spectroscopy (TRIR) supported by density functional theory (DFT). The intense absorption band of W(CNdipp)6 at 460 nm and that of W(CNdippPh(OMe2))6 at 500 nm originate from transitions of mixed ππ*(C≡N-C)/MLCT(W → Aryl) character, whereby W is depopulated by ca. 0.4 e(-) and the electron-density changes are predominantly localized along two equatorial molecular axes. The red shift and intensity rise on going from W(CNdipp)6 to W(CNdippPh(OMe2))6 are attributable to more extensive delocalization of the MLCT component. The complexes also exhibit absorptions in the 300-320 nm region, owing to W → C≡N MLCT transitions. Electronic absorptions in the spectrum of W(CNXy)6 (Xy = 2,6-dimethylphenyl), a complex with orthogonal aryl orientation, have similar characteristics, although shifted to higher energies. The relaxed lowest W(CNAryl)6 triplet state combines ππ* excitation of a trans pair of C≡N-C moieties with MLCT (0.21 e(-)) and ligand-to-ligand charge transfer (LLCT, 0.24-0.27 e(-)) from the other four CNAryl ligands to the axial aryl and, less, to C≡N groups; the spin density is localized along a single Aryl-N≡C-W-C≡N-Aryl axis. Delocalization of excited electron density on outer aryl rings in W(CNdippPh(OMe2))6 likely promotes photoinduced electron-transfer reactions to acceptor molecules. TRIR spectra show an intense broad bleach due to ν(C≡N), a prominent transient upshifted by 60-65 cm(-1), and a weak down-shifted feature due to antisymmetric C≡N stretch along the axis of high spin density. The TRIR spectral pattern remains unchanged on the femtosecond-nanosecond time scale, indicating that intersystem crossing and electron-density localization are ultrafast (<100 fs).
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Affiliation(s)
- Hana Kvapilová
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences , Dolejškova 3, CZ-182 23 Prague, Czech Republic.,Department of Inorganic Chemistry, University of Chemistry and Technology, Prague , Technická 5, CZ-166 28 Prague, Czech Republic
| | - Wesley Sattler
- Beckman Institute, California Institute of Technology , Pasadena, California 91125, United States
| | - Aaron Sattler
- Beckman Institute, California Institute of Technology , Pasadena, California 91125, United States
| | - Igor V Sazanovich
- Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Ian P Clark
- Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Michael Towrie
- Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Harry B Gray
- Beckman Institute, California Institute of Technology , Pasadena, California 91125, United States
| | - Stanislav Záliš
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences , Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Antonín Vlček
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences , Dolejškova 3, CZ-182 23 Prague, Czech Republic.,Queen Mary University of London , School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, United Kingdom
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24
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Vlček A, Kvapilová H, Towrie M, Záliš S. Electron-transfer acceleration investigated by time resolved infrared spectroscopy. Acc Chem Res 2015; 48:868-76. [PMID: 25699661 DOI: 10.1021/ar5004048] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Ultrafast electron transfer (ET) processes are important primary steps in natural and artificial photosynthesis, as well as in molecular electronic/photonic devices. In biological systems, ET often occurs surprisingly fast over long distances of several tens of angströms. Laser-pulse irradiation is conveniently used to generate strongly oxidizing (or reducing) excited states whose reactions are then studied by time-resolved spectroscopic techniques. While photoluminescence decay and UV-vis absorption supply precise kinetics data, time-resolved infrared absorption (TRIR) and Raman-based spectroscopies have the advantage of providing additional structural information and monitoring vibrational energy flows and dissipation, as well as medium relaxation, that accompany ultrafast ET. We will discuss three cases of photoinduced ET involving the Re(I)(CO)3(N,N) moiety (N,N = polypyridine) that occur much faster than would be expected from ET theories. [Re(4-N-methylpyridinium-pyridine)(CO)3(N,N)](2+) represents a case of excited-state picosecond ET between two different ligands that remains ultrafast even in slow-relaxing solvents, beating the adiabatic limit. This is caused by vibrational/solvational excitation of the precursor state and participation of high-frequency quantum modes in barrier crossing. The case of Re-tryptophan assemblies demonstrates that excited-state Trp → *Re(II) ET is accelerated from nanoseconds to picoseconds when the Re(I)(CO)3(N,N) chromophore is appended to a protein, close to a tryptophan residue. TRIR in combination with DFT calculations and structural studies reveals an interaction between the N,N ligand and the tryptophan indole. It results in partial electronic delocalization in the precursor excited state and likely contributes to the ultrafast ET rate. Long-lived vibrational/solvational excitation of the protein Re(I)(CO)3(N,N)···Trp moiety, documented by dynamic IR band shifts, could be another accelerating factor. The last discussed process, back-ET in a porphyrin-Re(I)(CO)3(N,N) dyad, demonstrates that formation of a hot product accelerates highly exergonic ET in the Marcus inverted region. Overall, it follows that ET can be accelerated by enhancing the electronic interaction and by vibrational excitation of the reacting system and its medium, stressing the importance of quantum nuclear dynamics in ET reactivity. These effects are experimentally accessible by time-resolved vibrational spectroscopies (IR, Raman) in combination with quantum chemical calculations. It is suggested that structural dynamics play different mechanistic roles in light-triggered ET involving electronically excited donors or acceptors than in ground-state processes. While TRIR spectroscopy is well suitable to elucidate ET processes on a molecular-level, transient 2D-IR techniques combining optical and two IR (or terahertz) laser pulses present future opportunities for investigating, driving, and controlling ET.
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Affiliation(s)
- Antonín Vlček
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Hana Kvapilová
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Michael Towrie
- Central Laser Facility, Research Complex at Harwell, STFC, Rutherford
Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Stanislav Záliš
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
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25
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Movsisyan L, Peeks MD, Greetham GM, Towrie M, Thompson AL, Parker AW, Anderson HL. Photophysics of threaded sp-carbon chains: the polyyne is a sink for singlet and triplet excitation. J Am Chem Soc 2014; 136:17996-8008. [PMID: 25474628 PMCID: PMC4353026 DOI: 10.1021/ja510663z] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Indexed: 01/24/2023]
Abstract
We have used single-crystal X-ray diffraction and time-resolved UV-NIR-IR absorption spectroscopy to gain insights into the structures and excited-state dynamics of a rotaxane consisting of a hexayne chain threaded through a phenanthroline macrocycle and a family of related compounds, including the rhenium(I) chlorocarbonyl complex of this rotaxane. The hexayne unit in the rhenium-rotaxane is severely nonlinear; it is bent into an arc with an angle of 155.6(1)° between the terminal C1 and C12 atoms and the centroid of the central C-C bond, with the most acute distortion at the point where the polyyne chain pushes against the Re(CO)3Cl unit. There are strong through-space excited-state interactions between the components of the rotaxanes. In the metal-free rotaxane, there is rapid singlet excitation energy transfer (EET) from the macrocycle to the hexayne (τ = 3.0 ps), whereas in the rhenium-rotaxane there is triplet EET, from the macrocycle complex (3)MLCT state to the hexayne (τ = 1.5 ns). This study revealed detailed information on the short-lived higher excited state of the hexayne (lifetime ∼1 ps) and on structural reorganization and cooling of hot polyyne chains, following internal conversion (over ∼5 ps). Comparison of the observed IR bands of the excited states of the hexayne with results from time-dependent density functional calculations (TD DFT) shows that these excited states have high cumulenic character (low bond length alternation) around the central region of the chain. These findings shed light on the complex interactions between the components of this supramolecular rotaxane and are important for the development of materials for the emerging molecular and nanoscale electronics.
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Affiliation(s)
- Levon
D. Movsisyan
- Department
of Chemistry, University of Oxford, Chemistry
Research Laboratory, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Martin D. Peeks
- Department
of Chemistry, University of Oxford, Chemistry
Research Laboratory, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Gregory M. Greetham
- Central
Laser Facility, Research Complex at Harwell, Science and Technology
Facilities Council, Harwell
Oxford, Didcot OX11 0QX, United Kingdom
| | - Michael Towrie
- Central
Laser Facility, Research Complex at Harwell, Science and Technology
Facilities Council, Harwell
Oxford, Didcot OX11 0QX, United Kingdom
| | - Amber L. Thompson
- Department
of Chemistry, University of Oxford, Chemistry
Research Laboratory, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Anthony W. Parker
- Central
Laser Facility, Research Complex at Harwell, Science and Technology
Facilities Council, Harwell
Oxford, Didcot OX11 0QX, United Kingdom
| | - Harry L. Anderson
- Department
of Chemistry, University of Oxford, Chemistry
Research Laboratory, Mansfield Road, Oxford OX1 3TA, United Kingdom
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Chu WK, Wei XG, Yiu SM, Ko CC, Lau KC. Strongly Phosphorescent Neutral Rhenium(I) Isocyanoborato Complexes: Synthesis, Characterization, and Photophysical, Electrochemical, and Computational Studies. Chemistry 2014; 21:2603-12. [DOI: 10.1002/chem.201405291] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Indexed: 11/08/2022]
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Kitanovic I, Can S, Alborzinia H, Kitanovic A, Pierroz V, Leonidova A, Pinto A, Spingler B, Ferrari S, Molteni R, Steffen A, Metzler-Nolte N, Wölfl S, Gasser G. A deadly organometallic luminescent probe: anticancer activity of a ReI bisquinoline complex. Chemistry 2014; 20:2496-507. [PMID: 24464824 DOI: 10.1002/chem.201304012] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Indexed: 12/25/2022]
Abstract
The photophysical properties of [Re(CO)3 (L-N3)]Br (L-N3 =2-azido-N,N-bis[(quinolin-2-yl)methyl]ethanamine), which could not be localized in cancer cells by fluorescence microscopy, have been revisited in order to evaluate its use as a luminescent probe in a biological environment. The Re(I) complex displays concentration-dependent residual fluorescence besides the expected phosphorescence, and the nature of the emitting excited states have been evaluated by DFT and time-dependent (TD) DFT methods. The results show that fluorescence occurs from a (1) LC/MLCT state, whereas phosphorescence mainly stems from a (3) LC state, in contrast to previous assignments. We found that our luminescent probe, [Re(CO)3 (L-N3)]Br, exhibits an interesting cytotoxic activity in the low micromolar range in various cancer cell lines. Several biochemical assays were performed to unveil the cytotoxic mechanism of the organometallic Re(I) bisquinoline complex. [Re(CO)3 (L-N3)]Br was found to be stable in human plasma indicating that [Re(CO)3 (L-N3)]Br itself and not a decomposition product is responsible for the observed cytotoxicity. Addition of [Re(CO)3 (L-N3)]Br to MCF-7 breast cancer cells grown on a biosensor chip micro-bioreactor immediately led to reduced cellular respiration and increased glycolysis, indicating a large shift in cellular metabolism and inhibition of mitochondrial activity. Further analysis of respiration of isolated mitochondria clearly showed that mitochondrial respiratory activity was a direct target of [Re(CO)3 (L-N3)]Br and involved two modes of action, namely increased respiration at lower concentrations, potentially through increased proton transport through the inner mitochondrial membrane, and efficient blocking of respiration at higher concentrations. Thus, we believe that the direct targeting of mitochondria in cells by [Re(CO)3 (L-N3)]Br is responsible for the anticancer activity.
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Affiliation(s)
- Igor Kitanovic
- Department of Bioanalytics and Molecular Biology, Institute for Pharmacy and Molecular Biology, University of Heidelberg im Neuenheimer Feld 364, 69120 Heidelberg (Germany), Tel: (+49) 622-1544-878 http://www.uni-heidelberg.de/fakultaeten/biowissenschaften/ipmb/biologie/woelfl/index.html
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Savéant JM. Concerted proton-electron transfers: fundamentals and recent developments. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2014; 7:537-560. [PMID: 25014349 DOI: 10.1146/annurev-anchem-071213-020315] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Proton-coupled electron transfers (PCET) are ubiquitous in natural and synthetic processes. This review focuses on reactions where the two events are concerted. Semiclassical models of such reactions allow their kinetic characterization through activation versus driving force relationships, estimates of reorganization energies, effects of the nature of the proton acceptor, and H/D kinetic isotope effect as well as their discrimination from stepwise pathways. Several homogeneous reactions (through stopped-flow and laser flash-quench techniques) and electrochemical processes are discussed in this framework. Once the way has been rid of the improper notion of pH-dependent driving force, water appears as a remarkable proton acceptor in terms of reorganization energy and pre-exponential factor, thanks to its H-bonded and H-bonding properties, similarly to purposely synthesized "H-bond train" molecules. The most recent developments are in modeling and description of emblematic concerted proton-electron transfer (CPET) reactions associated with the breaking of a heavy-atom bond in an all-concerted process.
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Affiliation(s)
- Jean-Michel Savéant
- Laboratoire d'Electrochimie Moléculaire, Unité Mixte de Recherche, Université Paris Diderot, Sorbonne Paris Cité, CNRS 7591, 75205 Paris Cedex 13, France;
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30
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Zeng Q, Messaoudani M, Vlček A, Hartl F. Temperature-dependent reduction pathways of complexes fac-[Re(CO)3(N-R-imidazole)(1,10-phenanthroline)]+ (R=H, CH3). Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2013.02.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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31
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Takematsu K, Williamson H, Blanco-Rodríguez AM, Sokolová L, Nikolovski P, Kaiser JT, Towrie M, Clark IP, Vlček A, Winkler JR, Gray HB. Tryptophan-accelerated electron flow across a protein-protein interface. J Am Chem Soc 2013; 135:15515-25. [PMID: 24032375 PMCID: PMC3855362 DOI: 10.1021/ja406830d] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report a new metallolabeled blue copper protein, Re126W122Cu(I) Pseudomonas aeruginosa azurin, which has three redox sites at well-defined distances in the protein fold: Re(I)(CO)3(4,7-dimethyl-1,10-phenanthroline) covalently bound at H126, a Cu center, and an indole side chain W122 situated between the Re and Cu sites (Re-W122(indole) = 13.1 Å, dmp-W122(indole) = 10.0 Å, Re-Cu = 25.6 Å). Near-UV excitation of the Re chromophore leads to prompt Cu(I) oxidation (<50 ns), followed by slow back ET to regenerate Cu(I) and ground-state Re(I) with biexponential kinetics, 220 ns and 6 μs. From spectroscopic measurements of kinetics and relative ET yields at different concentrations, it is likely that the photoinduced ET reactions occur in protein dimers, (Re126W122Cu(I))2 and that the forward ET is accelerated by intermolecular electron hopping through the interfacial tryptophan: *Re//←W122←Cu(I), where // denotes a protein-protein interface. Solution mass spectrometry confirms a broad oligomer distribution with prevalent monomers and dimers, and the crystal structure of the Cu(II) form shows two Re126W122Cu(II) molecules oriented such that redox cofactors Re(dmp) and W122-indole on different protein molecules are located at the interface at much shorter intermolecular distances (Re-W122(indole) = 6.9 Å, dmp-W122(indole) = 3.5 Å, and Re-Cu = 14.0 Å) than within single protein folds. Whereas forward ET is accelerated by hopping through W122, BET is retarded by a space jump at the interface that lacks specific interactions or water molecules. These findings on interfacial electron hopping in (Re126W122Cu(I))2 shed new light on optimal redox-unit placements required for functional long-range charge separation in protein complexes.
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Affiliation(s)
- Kana Takematsu
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Heather Williamson
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Ana María Blanco-Rodríguez
- Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, United Kingdom
| | - Lucie Sokolová
- Institute of Physical and Theoretical Chemistry, Goethe-Universität, Max-von-Laue-Str. 7, 60438 Frankfurt am Main, Germany
| | - Pavle Nikolovski
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Jens T. Kaiser
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Michael Towrie
- Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire, OX11 0FA, UK
| | - Ian P. Clark
- Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire, OX11 0FA, UK
| | - Antonín Vlček
- Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, United Kingdom
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Jay R. Winkler
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Harry B. Gray
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
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32
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Warren JJ, Herrera N, Hill MG, Winkler JR, Gray HB. Electron flow through nitrotyrosinate in Pseudomonas aeruginosa azurin. J Am Chem Soc 2013; 135:11151-8. [PMID: 23859602 DOI: 10.1021/ja403734n] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We have designed ruthenium-modified Pseudomonas aeruginosa azurins that incorporate 3-nitrotyrosine (NO2YOH) between Ru(2,2'-bipyridine)2(imidazole)(histidine) and Cu redox centers in electron transfer (ET) pathways. We investigated the structures and reactivities of three different systems: RuH107NO2YOH109, RuH124NO2YOH122, and RuH126NO2YOH122. RuH107NO2YOH109, unlabeled H124NO2YOH122, and unlabeled H126NO2YOH122 were structurally characterized. The pKa's of NO2YOH at positions 122 and 109 are 7.2 and 6.0, respectively. Reduction potentials of 3-nitrotyrosinate (NO2YO(-))-modified azurins were estimated from cyclic and differential pulse voltammetry data: oxidation of NO2YO(-)122 occurs near 1.1 versus NHE; oxidation of NO2YO(-)109 is near 1.2 V. Our analysis of transient optical spectroscopic experiments indicates that hopping via NO2YO(-) enhances Cu(I) oxidation rates over single-step ET by factors of 32 (RuH107NO2YO(-)109), 46 (RuH126NO2YO(-)122), and 13 (RuH124NO2YO(-)122).
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Affiliation(s)
- Jeffrey J Warren
- Beckman Institute and Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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33
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Syntheses and photophysical studies of new classes of luminescent isocyano rhenium(I) diimine complexes. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2012.01.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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34
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Weinberg DR, Gagliardi CJ, Hull JF, Murphy CF, Kent CA, Westlake BC, Paul A, Ess DH, McCafferty DG, Meyer TJ. Proton-Coupled Electron Transfer. Chem Rev 2012; 112:4016-93. [DOI: 10.1021/cr200177j] [Citation(s) in RCA: 1125] [Impact Index Per Article: 93.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- David R. Weinberg
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
- Department of Physical and Environmental
Sciences, Colorado Mesa University, 1100 North Avenue, Grand Junction,
Colorado 81501-3122, United States
| | - Christopher J. Gagliardi
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Jonathan F. Hull
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Christine Fecenko Murphy
- Department
of Chemistry, B219
Levine Science Research Center, Box 90354, Duke University, Durham,
North Carolina 27708-0354, United States
| | - Caleb A. Kent
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Brittany C. Westlake
- The American Chemical Society,
1155 Sixteenth Street NW, Washington, District of Columbia 20036,
United States
| | - Amit Paul
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Daniel H. Ess
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Dewey Granville McCafferty
- Department
of Chemistry, B219
Levine Science Research Center, Box 90354, Duke University, Durham,
North Carolina 27708-0354, United States
| | - Thomas J. Meyer
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
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35
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Zobi F, Spingler B. Post-protein-binding reactivity and modifications of the fac-[Re(CO)3]+ core. Inorg Chem 2012; 51:1210-2. [PMID: 22229733 DOI: 10.1021/ic2023314] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The reactivity of the [Re(CO)(3)(H(2)O)(2)](+) complex coordinated to the His15 residue of HEW lysozyme is described. In the fully metalated protein (Lys-1), the Re ion retains its reactivity only toward selected ligands, while others induce a ligand-mediated demetalation of the enzyme. It is further shown that some of the complexes that may be "engineered" on the lysozyme do not react with the free protein even if present in solution in excess. The formation of stable metal adducts starting from Lys-1 was confirmed by X-ray crystallography.
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Affiliation(s)
- Fabio Zobi
- Institute of Inorganic Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
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36
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Zeng Q, Messaoudani M, Vlček A, Hartl F. Electrochemical Reductive Deprotonation of an Imidazole Ligand in a Bipyridine Tricarbonyl Rhenium(I) Complex. Eur J Inorg Chem 2011. [DOI: 10.1002/ejic.201101100] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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37
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Olmon ED, Sontz PA, Blanco-Rodríguez AM, Towrie M, Clark IP, Vlček A, Barton JK. Charge photoinjection in intercalated and covalently bound [Re(CO)3(dppz)(py)]+-DNA constructs monitored by time-resolved visible and infrared spectroscopy. J Am Chem Soc 2011; 133:13718-30. [PMID: 21827149 PMCID: PMC3227519 DOI: 10.1021/ja205568r] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The complex [Re(CO)(3)(dppz)(py'-OR)](+) (dppz = dipyrido[3,2-a:2',3'-c]phenazine; py'-OR = 4-functionalized pyridine) offers IR sensitivity and can oxidize DNA directly from the excited state, making it a promising probe for the study of DNA-mediated charge transport (CT). The behavior of several covalent and noncovalent Re-DNA constructs was monitored by time-resolved IR (TRIR) and UV/visible spectroscopies, as well as biochemical methods, confirming the long-range oxidation of DNA by the excited complex. Optical excitation of the complex leads to population of MLCT and at least two distinct intraligand states. Experimental observations that are consistent with charge injection from these excited states include similarity between long-time TRIR spectra and the reduced state spectrum observed by spectroelectrochemistry, the appearance of a guanine radical signal in TRIR spectra, and the eventual formation of permanent guanine oxidation products. The majority of reactivity occurs on the ultrafast time scale, although processes dependent on slower conformational motions of DNA, such as the accumulation of oxidative damage at guanine, are also observed. The ability to measure events on such disparate time scales, its superior selectivity in comparison to other spectroscopic techniques, and the ability to simultaneously monitor carbonyl ligand and DNA IR absorption bands make TRIR a valuable tool for the study of CT in DNA.
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Affiliation(s)
- Eric D Olmon
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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38
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Lo KK, Zhang KY, Li SP. Recent Exploitation of Luminescent Rhenium(I) Tricarbonyl Polypyridine Complexes as Biomolecular and Cellular Probes. Eur J Inorg Chem 2011. [DOI: 10.1002/ejic.201100469] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Kenneth Kam‐Wing Lo
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China, Fax: +852‐3442‐0522
| | - Kenneth Yin Zhang
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China, Fax: +852‐3442‐0522
| | - Steve Po‐Yam Li
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China, Fax: +852‐3442‐0522
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39
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Blanco-Rodríguez AM, Towrie M, Sýkora J, Záliš S, Vlček A. Photoinduced Intramolecular Tryptophan Oxidation and Excited-State Behavior of [Re(L-AA)(CO)3(α-diimine)]+ (L = Pyridine or Imidazole, AA = Tryptophan, Tyrosine, Phenylalanine). Inorg Chem 2011; 50:6122-34. [DOI: 10.1021/ic200252z] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ana María Blanco-Rodríguez
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
| | - Mike Towrie
- Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - J. Sýkora
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Stanislav Záliš
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
| | - Antonín Vlček
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-182 23 Prague, Czech Republic
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40
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Blanco-Rodríguez AM, Di Bilio AJ, Shih C, Museth AK, Clark IP, Towrie M, Cannizzo A, Sudhamsu J, Crane BR, Sýkora J, Winkler JR, Gray HB, Záliš S, Vlček A. Phototriggering electron flow through Re(I)-modified Pseudomonas aeruginosa azurins. Chemistry 2011; 17:5350-61. [PMID: 21469225 DOI: 10.1002/chem.201002162] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 12/12/2010] [Indexed: 11/07/2022]
Abstract
The [Re(I)(CO)(3)(4,7-dimethyl-1,10-phenanthroline)(histidine-124)(tryptophan-122)] complex, denoted [Re(I)(dmp)(W122)], of Pseudomonas aeruginosa azurin behaves as a single photoactive unit that triggers very fast electron transfer (ET) from a distant (2 nm) Cu(I) center in the protein. Analysis of time-resolved (ps-μs) IR spectroscopic and kinetics data collected on [Re(I)(dmp)(W122)AzM] (in which M=Zn(II), Cu(II), Cu(I); Az=azurin) and position-122 tyrosine (Y), phenylalanine (F), and lysine (K) mutants, together with excited-state DFT/time-dependent (TD)DFT calculations and X-ray structural characterization, reveal the character, energetics, and dynamics of the relevant electronic states of the [Re(I)(dmp)(W122)] unit and a cascade of photoinduced ET and relaxation steps in the corresponding Re-azurins. Optical population of [Re(I)(imidazole-H124)(CO)(3)]→dmp (1)CT states (CT=charge transfer) is followed by around 110 fs intersystem crossing and about 600 ps structural relaxation to a (3)CT state. The IR spectrum indicates a mixed Re(I)(CO)(3),A→dmp/π→π(*)(dmp) character for aromatic amino acids A122 (A=W, Y, F) and Re(I)(CO)(3)→dmp metal-ligand charge transfer (MLCT) for [Re(I)(dmp)(K122)AzCu(II)]. In a few ns, the (3)CT state of [Re(I)(dmp)(W122)AzM] establishes an equilibrium with the [Re(I)(dmp(.-))(W122(.+))AzM] charge-separated state, (3)CS, whereas the (3)CT state of the other Y, F, and K122 proteins decays to the ground state. In addition to this main pathway, (3)CS is populated by fs- and ps-W(indole)→Re(II) ET from (1)CT and the initially "hot" (3)CT states, respectively. The (3)CS state undergoes a tens-of-ns dmp(.-)→W122(.+) ET recombination leading to the ground state or, in the case of the Cu(I) azurin, a competitively fast (≈30 ns over 1.12 nm) Cu(I)→W(.+) ET, to give [Re(I)(dmp(.-))(W122)AzCu(II)]. The overall photoinduced Cu(I)→Re(dmp) ET through [Re(I)(dmp)(W122)AzCu(I)] occurs over a 2 nm distance in <50 ns after excitation, with the intervening fast (3)CT-(3)CS equilibrium being the principal accelerating factor. No reaction was observed for the three Y, F, and K122 analogues. Although the presence of [Re(dmp)(W122)AzCu(II)] oligomers in solution was documented by mass spectrometry and phosphorescence anisotropy, the kinetics data do not indicate any significant interference from the intermolecular ET steps. The ground-state dmp-indole π-π interaction together with well-matched W/W(.+) and excited-state [Re(II)(CO)(3)(dmp(.-))]/[Re(I)(CO)(3)(dmp(.-))] potentials that result in very rapid electron interchange and (3)CT-(3)CS energetic proximity, are the main factors responsible for the unique ET behavior of [Re(I)(dmp)(W122)]-containing azurins.
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Affiliation(s)
- Ana María Blanco-Rodríguez
- Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, UK
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41
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Sokolová L, Williamson H, Sýkora J, Hof M, Gray HB, Brutschy B, Vlcek A. Mass spectrometric characterization of oligomers in Pseudomonas aeruginosa azurin solutions. J Phys Chem B 2011; 115:4790-800. [PMID: 21452827 DOI: 10.1021/jp110460k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have employed laser-induced liquid bead ion desorption mass spectroscopy (LILBID MS) to study the solution behavior of Pseudomonas aeruginosa azurin as well as two mutants and corresponding Re-labeled derivatives containing a Re(CO)(3)(4,7-dimethyl-1,10-phenanthroline)(+) chromophore appended to a surface histidine. LILBID spectra show broad oligomer distributions whose particular patterns depend on the solution composition (pure H(2)O, 20-30 mM NaCl, 20 and 50 mM NaP(i) or NH(4)P(i) at pH = 7). The distribution maximum shifts to smaller oligomers upon decreasing the azurin concentration and increasing the buffer concentration. Oligomerization is less extensive for native azurin than its mutants. The oligomerization propensities of unlabeled and Re-labeled proteins are generally comparable, and only Re126 shows some preference for the dimer that persists even in highly diluted solutions. Peak shifts to higher masses and broadening in 20-50 mM NaP(i) confirm strong azurin association with buffer ions and solvation. We have found that LILBID MS reveals the solution behavior of weakly bound nonspecific protein oligomers, clearly distinguishing individual components of the oligomer distribution. Independently, average data on oligomerization and the dependence on solution composition were obtained by time-resolved anisotropy of the Re-label photoluminescence that confirmed relatively long rotation correlation times, 6-30 ns, depending on Re-azurin and solution composition. Labeling proteins with Re-chromophores that have long-lived phosphorescence extends the time scale of anisotropy measurements to hundreds of nanoseconds, thereby opening the way for investigations of large oligomers with long rotation times.
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Affiliation(s)
- Lucie Sokolová
- Institute of Physical and Theoretical Chemistry, Goethe University, Frankfurt am Main, Germany
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Jha A, Ishii K, Udgaonkar JB, Tahara T, Krishnamoorthy G. Exploration of the Correlation between Solvation Dynamics and Internal Dynamics of a Protein. Biochemistry 2010; 50:397-408. [DOI: 10.1021/bi101440c] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Anjali Jha
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Kunihiko Ishii
- Molecular Spectroscopy Laboratory, Advanced Science Institute (ASI), RIKEN, Wako, Saitama 351-0198, Japan
| | - Jayant B. Udgaonkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, India
| | - Tahei Tahara
- Molecular Spectroscopy Laboratory, Advanced Science Institute (ASI), RIKEN, Wako, Saitama 351-0198, Japan
| | - G. Krishnamoorthy
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
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Ko CC, Lo LTL, Ng CO, Yiu SM. Photochemical Synthesis of Intensely Luminescent Isocyano Rhenium(I) Complexes with Readily Tunable Structural Features. Chemistry 2010; 16:13773-82. [DOI: 10.1002/chem.201000793] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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El Nahhas A, Cannizzo A, van Mourik F, Blanco-Rodríguez AM, Zális S, Vlcek A, Chergui M. Ultrafast excited-state dynamics of [Re(L)(CO)3(bpy)]n complexes: involvement of the solvent. J Phys Chem A 2010; 114:6361-9. [PMID: 20465299 DOI: 10.1021/jp101999m] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ultrafast excited-state dynamics of [Re(L)(CO)(3)(bpy)](n) (L = Cl, Br, n = 0; L = 4-ethyl-pyridine (Etpy), n = 1+; bpy = 2,2'-bipyridine) have been investigated in dimethylformamide (DMF) solution by fluorescence up-conversion (FlUC) and UV-vis transient absorption (TA) with approximately 100 fs time resolution. TA was also measured in the [1-ethyl-3-methyl-imidazolium]BF(4) ionic liquid. The complexes show a very broad fluorescence band at 540-550 nm at zero time delay, which decays with 100-140 fs (depending on L) by intersystem crossing (ISC) to a pipi* intraligand ((3)IL) and a Re(L)(CO)(3) --> bpy charge-transfer ((3)CT) excited states. A second emission decay component (1.1-1.7 ps), apparent in the red part of the spectrum, is attributed to (3)IL --> (3)CT conversion, leaving phosphorescence from the lowest (3)CT state as the only emission signal at longer time delays. The triplet conversion is slower in DMF than acetonitrile, commensurate with solvation times. Full assignment of the excited-state absorption at long delay times is obtained by TD-DFT calculations on the lowest triplet state, showing that the 373 nm band is the sole diagnostics of bpy reduction in the CT excited state. Bands in the visible are due to Ligand-to-Metal-Charge-Transfer (LMCT) transitions. Time-resolved UV-vis absorption spectra exhibit a units-of-ps rise of all absorption features attributed to (3)IL --> (3)CT conversion as well as electronic and vibrational relaxation, and a approximately 15 ps rise of only the 373 nm pipi*(bpy(*-)) band, which slows down to approximately 1 ns in the ionic liquid solvent. It is proposed that this slow relaxation originates mainly from restructuring of solvent molecules that are found very close to the metal center, inserted between the ligands. The solvent thus plays a key role in controlling the intramolecular charge separation, and this effect may well be operative in other classes of metal-based molecular complexes.
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Affiliation(s)
- Amal El Nahhas
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, ISIC-FSB, station 6, CH-1015 Lausanne, Switzerland
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Herrick RS, Ziegler CJ, Gambella A. Reactions of [Re(CO)3]+ with Histidylhistidine and Modified Histidines. Eur J Inorg Chem 2010. [DOI: 10.1002/ejic.201000532] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Keyes TE, Forster RJ, Blackledge C. Time resolved spectroscopy of inorganic complexes. SPECTROSCOPIC PROPERTIES OF INORGANIC AND ORGANOMETALLIC COMPOUNDS 2010. [DOI: 10.1039/9781849730853-00211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Time resolved spectroscopy has revolutionised our understanding of photochemical and photophysical reactions of inorganic complexes. In this review, we briefly describe the most common time resolved optical spectroscopic methods applied to inorganic complexes and outline some examples and highlights from the recent literature. The review is not intended to be exhaustive, but highlights key recent papers from coordination chemistry, supramolecular chemistry, carbonyl chemistry and bioinorganic chemistry, as well as, recent insights from ultrafast spectroscopy into the photophysics of important prototypes such as [Ru(bpy)3]2+ and [Cu(dmp)2]+. A brief perspective is then presented which discusses areas where time resolved spectroscopy of inorganic complexes could play a particularly important role in the next few years.
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Affiliation(s)
- Tia E. Keyes
- National Biophotonics and Imaging Platform School of Chemical Sciences, Dublin City University Glasnevin, Dublin 7 Ireland
| | - Robert J. Forster
- National Biophotonics and Imaging Platform School of Chemical Sciences, Dublin City University Glasnevin, Dublin 7 Ireland
| | - Charles Blackledge
- National Biophotonics and Imaging Platform School of Chemical Sciences, Dublin City University Glasnevin, Dublin 7 Ireland
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Wojdyla M, Smith JA, Vasudevan S, Quinn SJ, Kelly JM. Excited state behaviour of substituted dipyridophenazine Cr(III) complexes in the presence of nucleic acids. Photochem Photobiol Sci 2010; 9:1196-202. [PMID: 20617266 DOI: 10.1039/c0pp00110d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photophysics and photochemistry of [Cr(phen)(2)(dppz)](3+) and its 11,12-substituted derivatives [Cr(phen)(2)(X(2)dppz)](3+) {X = Me or F} have been studied in the presence of purine nucleotides or DNA using steady state and time-resolved absorption and luminescence spectroscopy. 5'-Adenosine monophosphate (5'-AMP) shows only a weak interaction with the excited states of each complex. By contrast they are efficiently quenched by 5'-guanosine monophosphate (5'-GMP), consistent with photo-induced electron transfer. Laser flash photolysis spectroscopy in the presence of 5'-GMP suggests that both forward and back electron-transfers are rapid. All complexes also display a strong affinity for DNA and evidence for both static and dynamic quenching mechanisms is provided.
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Affiliation(s)
- Michal Wojdyla
- School of Chemistry, University of Dublin, Trinity College, College Green, Dublin 2, Republic of Ireland
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Affiliation(s)
- My Hang V Huynh
- DE-1: High Explosive Science and Technology Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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