Time-Dependent DFT Studies of Metal Core-Electron Excitations in Mn Complexes

Jaszewski, Adrian R.; Stranger, Rob; Pace, Ronald

doi:10.1021/jp803286c

Cited by 22 publications

(39 citation statements)

References 98 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…First we examine the available Mn K-edge XANES data on various PS II preparations and compare these with computational results for model OEC clusters by using the three {Mn 4 /Ca} structure motifs we had earlier identified. [22,23] We use the TDDFT computational XANES methodology, a combined theoretical/phenomenological approach, [16,26] we had recently developed for Mn systems, the results from which we have summarized below. One of the structural motifs that we regard as the one that most probably resembles the steady-state functional turnover configuration of the cluster [25] is further examined in terms of its predicted S-state Mn XANES energies.…”

Section: Resultsmentioning

confidence: 99%

“…b) Single turnover data (plant and cyanobacterial PS II) from continuous low-temperature illumination advancement (inflection point): ! : Guiles et al (1990); [29] [16,26] for these compounds. The calculations generate energies and intensities for a class of closely spaced dipole-allowed one-electron excitations corresponding to Mn (1s)!Mn (4p igand) orbitals, the latter normally unoccupied.…”

Section: Resultsmentioning

confidence: 99%

“…2) A new methodology that uses time-dependent DFT (TDDFT) computations to semitheoretically predict Mn XANES edge positions for model Mn systems of defined oxidation state and ligand geometry. [16,26] We have examined the results of these calculations, in combination, by comparison with the extensive Mn K-edge XANES data on PS II now available, particularly those results for the individual S-state edge energies obtained by deconvolution of flash turnover sequences. As before, [22][23][24][25] we first considered all three of the model structures that we had previously examined as a function of progressive total oxidation state.…”

Section: O 4 a C H T U N G T R E N N U N G (N 2 C 3 H 4 )-A C H T U Nmentioning

confidence: 99%

See 2 more Smart Citations

Toward the Assignment of the Manganese Oxidation Pattern in the Water‐Oxidizing Complex of Photosystem II: A Time‐Dependent DFT Study of XANES Energies

Jaszewski

Petrie

Pace

et al. 2011

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations are reported on three sets of isomeric models of the {Mn(4)/Ca} water-oxidizing complex of photosystem II (PS II), which share the general formula [CaMn(4)O(4)(N(2)C(3)H(4))(RCOO)(6)](q)⋅(H(2)O)(n) (R=H, CH(3); q=-1, 0, +1, +2; n=3, 4, 5, 6, 7). Comparison with the full range of available data on Mn K-edge X-ray absorption energy values determined for the photosystem allows us to validate the structures that correspond to the particular S states and to determine their Mn oxidation patterns. By using a new TDDFT procedure, it is shown that variations in the absolute K-edge energy values for a particular S state, reported by different research groups, can be quantitatively explained by different geometries adopted by the Mn cluster, which demonstrates flexibility in the position of the fourth 'dangling' Mn atom in relation to a cubane structure created by the Ca atom and the three other Mn atoms. Computational results show that each step of the S cycle occurs by removal of one electron directly from the Mn cluster. This Mn-centered oxidation still agrees with the small difference observed experimentally between the K-edge energy values of the S(2) and S(3) states of the photosystem, thus resolving a controversy as to whether this represents ligand-centered or metal-centered oxidation. The overall oxidation state of Mn atoms in the tetramanganese cluster during functional turnover changes from 2.75 for S(0), 3.00 for S(1), and 3.25 for S(2) up to 3.50 for the S(3) state, which is systematically 0.50 lower than the previously proposed oxidation states of the cluster. The calculations give insight into why these earlier, purely empirical, assignments of the Mn oxidation levels in PS II could be in error.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: O 4 a C H T U N G T R E N N U N G (N 2 C 3 H 4 )-A C H T U Nmentioning

confidence: 99%

See 1 more Smart Citation

Toward the Assignment of the Manganese Oxidation Pattern in the Water‐Oxidizing Complex of Photosystem II: A Time‐Dependent DFT Study of XANES Energies

Jaszewski

Petrie

Pace

et al. 2011

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

show abstract

“…In the present study a ∆SCF Kohn Sham 30,32 method has been used in contrast to the previous study which used the TDDFT method. 24,25 The present method was chosen based both on its inherent superior properties and on previous experience. 32,36 The static exchange spectrum is constructed from a fully optimized core hole or a transition potential, allowing inclusion of orbital relaxation around the core hole, and avoiding the electron self-energy problem -two factors that increase steeply as one moves down the main shells of an atom.…”

Section: Discussionmentioning

confidence: 99%

Modeling Near-Edge Fine Structure X-ray Spectra of the Manganese Catalytic Site for Water Oxidation in Photosystem II

2012

View full text Add to dashboard Cite

The Mn 1s Near Edge Absorption Fine Structure (NEXAFS) has been computed by means of transition potential gradient corrected Density Functional Theory (DFT) on four Mn 4 Ca clusters modeling the successive S 0 to S 3 steps of the oxygen evolving complex (OEC) in photosystem II (PSII). The model clusters were obtained from a previous theoretical study where they were determined by energy minimization. They are composed of Mn(III) and Mn(IV) atoms, progressing from Mn(III) 3 Mn(IV) for S 0 , to Mn(III) 2 Mn(IV) 2 for S 1 , to Mn(III)Mn(IV) 3 for S 2 , and to * To whom correspondence should be addressed † Uppsala University ‡ Stockholm University ¶ Royal Institute of Technology 1 Mn(IV) 4 for S 3 , implying an Mn centered oxidation during each step of the photosynthetic oxygen evolution. The DFT simulations of the Mn 1s absorption edge reproduce the experimentally measured curves quite well. Using the half-height method, the theoretical IPE's are shifted by 0.93 eV for the S 0 to S 1 transition, by 1.43 eV for the S 1 to S 2 transition, and by 0.63 eV for the S 2 to S 3 transition. The IPE shifts depend strongly on the method used to determine them, and the most interesting result is that the present clusters reproduce the shift in the S 2 to S 3 transition obtained both with the half-height and with the second derivative methods, thus giving strong support to the previously suggested structures and assignments.

show abstract

“…With relevance to potential catalytic intermediates involved in the water oxidation chemistry of PSII, Yano et al (2007) have successfully correlated TD-DFT and experimental pre-edge spectra (1s to 3d excitations) of mononuclear Mn(V) nitrido and oxo compounds. More recently, Jaszewski et al (2008) performed TD-DFT calculations of Mn core excitations in a series of Mn complexes with nitrogen and oxygen donor ligands. Excitations were allowed not only from 1s but also from 2p orbitals, yielding results that could be compared with 1s2p resonant inelastic X-ray scattering (RIXS) studies.…”

Section: Optical Spectramentioning

confidence: 99%

The Density Functional Theory

Lipparini¹

2008

Modern Many-Particle Physics

View full text Add to dashboard Cite

Density functional theory (DFT) finds increasing use in applications related to biological systems. Advancements in methodology and implementations have reached a point where predicted properties of reasonable to high quality can be obtained. Thus, DFT studies can complement experimental investigations, or even venture with some confidence into experimentally unexplored territory. In the present contribution, we provide an overview of the properties that can be calculated with DFT, such as geometries, energies, reaction mechanisms, and spectroscopic properties. A wide range of spectroscopic parameters is nowadays accessible with DFT, including quantities related to infrared and optical spectra, X-ray absorption and Mössbauer, as well as all of the magnetic properties connected with electron paramagnetic resonance spectroscopy except relaxation times. We highlight each of these fields of application with selected examples from the recent literature and comment on the capabilities and limitations of current methods.

show abstract

Time-Dependent DFT Studies of Metal Core-Electron Excitations in Mn Complexes

Cited by 22 publications

References 98 publications

Toward the Assignment of the Manganese Oxidation Pattern in the Water‐Oxidizing Complex of Photosystem II: A Time‐Dependent DFT Study of XANES Energies

Toward the Assignment of the Manganese Oxidation Pattern in the Water‐Oxidizing Complex of Photosystem II: A Time‐Dependent DFT Study of XANES Energies

Modeling Near-Edge Fine Structure X-ray Spectra of the Manganese Catalytic Site for Water Oxidation in Photosystem II

The Density Functional Theory

Contact Info

Product

Resources

About