1
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Fritsch L, Rehsies P, Barakat W, Estes DP, Bauer M. Detection and Characterization of Hydride Ligands in Copper Complexes by Hard X-Ray Spectroscopy. Chemistry 2024; 30:e202400357. [PMID: 38651986 DOI: 10.1002/chem.202400357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 04/17/2024] [Accepted: 04/18/2024] [Indexed: 04/25/2024]
Abstract
Transition metal complexes, particularly copper hydrides, play an important role in various catalytic processes and molecular inorganic chemistry. This study employs synchrotron hard X-ray spectroscopy to gain insights into the geometric and electronic properties of copper hydrides as potential catalysts for CO2 hydrogenation. The potential of high energy resolution X-ray absorption near-edge structure (HERFD-XANES) and valence-to-core X-ray emission (VtC-XES) is demonstrated with measurement on Stryker's reagent (Cu6H6) and [Cu3(μ3-H)(dpmppe)2](PF6)2 (Cu3H), alongside a non-hydride copper compound ICu(dtbppOH) (Cuy-I). The XANES analysis reveals that coordination geometries strongly influence the spectra, providing only indirect details about hydride coordination. The VtC-XES analysis exhibits a distinct signal around 8975 eV, offering a diagnostic tool to identify hydride ligands. Theoretical calculations support and extend these findings by comparing hydride-containing complexes with their hydride-free counterparts.
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Affiliation(s)
- Lorena Fritsch
- Institute of Inorganic Chemistry and Center for Sustainable Systems Design (CSSD), Paderborn University, Warburger Straße 100, 33098, Paderborn, Germany
| | - Pia Rehsies
- Institute of Inorganic Chemistry and Center for Sustainable Systems Design (CSSD), Paderborn University, Warburger Straße 100, 33098, Paderborn, Germany
| | - Wael Barakat
- Instritute of Technical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Deven P Estes
- Instritute of Technical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Matthias Bauer
- Institute of Inorganic Chemistry and Center for Sustainable Systems Design (CSSD), Paderborn University, Warburger Straße 100, 33098, Paderborn, Germany
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2
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Hwang IH, Kelly SD, Chan MKY, Stavitski E, Heald SM, Han SW, Schwarz N, Sun CJ. The AXEAP2 program for Kβ X-ray emission spectra analysis using artificial intelligence. JOURNAL OF SYNCHROTRON RADIATION 2023; 30:923-933. [PMID: 37526993 PMCID: PMC10481262 DOI: 10.1107/s1600577523005684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 06/26/2023] [Indexed: 08/03/2023]
Abstract
The processing and analysis of synchrotron data can be a complex task, requiring specialized expertise and knowledge. Our previous work addressed the challenge of X-ray emission spectrum (XES) data processing by developing a standalone application using unsupervised machine learning. However, the task of analyzing the processed spectra remains another challenge. Although the non-resonant Kβ XES of 3d transition metals are known to provide electronic structure information such as oxidation and spin state, finding appropriate parameters to match experimental data is a time-consuming and labor-intensive process. Here, a new XES data analysis method based on the genetic algorithm is demonstrated, applying it to Mn, Co and Ni oxides. This approach is also implemented as a standalone application, Argonne X-ray Emission Analysis 2 (AXEAP2), which finds a set of parameters that result in a high-quality fit of the experimental spectrum with minimal intervention. AXEAP2 is able to find a set of parameters that reproduce the experimental spectrum, and provide insights into the 3d electron spin state, 3d-3p electron exchange force and Kβ emission core-hole lifetime.
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Affiliation(s)
- In-Hui Hwang
- X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Shelly D. Kelly
- X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Maria K. Y. Chan
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Eli Stavitski
- National Synchrotron Light Source II, Brookhaven National Laboratory, NY 11973, USA
| | - Steve M. Heald
- X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Sang-Wook Han
- Department of Physics Education and Institute of Fusion Science, Jeonbuk National University, Jeonju 54896, Republic of Korea
| | - Nicholas Schwarz
- X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Cheng-Jun Sun
- X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
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3
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Cutsail III GE, DeBeer S. Challenges and Opportunities for Applications of Advanced X-ray Spectroscopy in Catalysis Research. ACS Catal 2022. [DOI: 10.1021/acscatal.2c01016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- George E. Cutsail III
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
- Institute of Inorganic Chemistry, University of Duisburg-Essen, Universitätsstr. 5-7, 45117 Essen, Germany
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
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4
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Yang Y, Peltier CR, Zeng R, Schimmenti R, Li Q, Huang X, Yan Z, Potsi G, Selhorst R, Lu X, Xu W, Tader M, Soudackov AV, Zhang H, Krumov M, Murray E, Xu P, Hitt J, Xu L, Ko HY, Ernst BG, Bundschu C, Luo A, Markovich D, Hu M, He C, Wang H, Fang J, DiStasio RA, Kourkoutis LF, Singer A, Noonan KJT, Xiao L, Zhuang L, Pivovar BS, Zelenay P, Herrero E, Feliu JM, Suntivich J, Giannelis EP, Hammes-Schiffer S, Arias T, Mavrikakis M, Mallouk TE, Brock JD, Muller DA, DiSalvo FJ, Coates GW, Abruña HD. Electrocatalysis in Alkaline Media and Alkaline Membrane-Based Energy Technologies. Chem Rev 2022; 122:6117-6321. [PMID: 35133808 DOI: 10.1021/acs.chemrev.1c00331] [Citation(s) in RCA: 89] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hydrogen energy-based electrochemical energy conversion technologies offer the promise of enabling a transition of the global energy landscape from fossil fuels to renewable energy. Here, we present a comprehensive review of the fundamentals of electrocatalysis in alkaline media and applications in alkaline-based energy technologies, particularly alkaline fuel cells and water electrolyzers. Anion exchange (alkaline) membrane fuel cells (AEMFCs) enable the use of nonprecious electrocatalysts for the sluggish oxygen reduction reaction (ORR), relative to proton exchange membrane fuel cells (PEMFCs), which require Pt-based electrocatalysts. However, the hydrogen oxidation reaction (HOR) kinetics is significantly slower in alkaline media than in acidic media. Understanding these phenomena requires applying theoretical and experimental methods to unravel molecular-level thermodynamics and kinetics of hydrogen and oxygen electrocatalysis and, particularly, the proton-coupled electron transfer (PCET) process that takes place in a proton-deficient alkaline media. Extensive electrochemical and spectroscopic studies, on single-crystal Pt and metal oxides, have contributed to the development of activity descriptors, as well as the identification of the nature of active sites, and the rate-determining steps of the HOR and ORR. Among these, the structure and reactivity of interfacial water serve as key potential and pH-dependent kinetic factors that are helping elucidate the origins of the HOR and ORR activity differences in acids and bases. Additionally, deliberately modulating and controlling catalyst-support interactions have provided valuable insights for enhancing catalyst accessibility and durability during operation. The design and synthesis of highly conductive and durable alkaline membranes/ionomers have enabled AEMFCs to reach initial performance metrics equal to or higher than those of PEMFCs. We emphasize the importance of using membrane electrode assemblies (MEAs) to integrate the often separately pursued/optimized electrocatalyst/support and membranes/ionomer components. Operando/in situ methods, at multiscales, and ab initio simulations provide a mechanistic understanding of electron, ion, and mass transport at catalyst/ionomer/membrane interfaces and the necessary guidance to achieve fuel cell operation in air over thousands of hours. We hope that this Review will serve as a roadmap for advancing the scientific understanding of the fundamental factors governing electrochemical energy conversion in alkaline media with the ultimate goal of achieving ultralow Pt or precious-metal-free high-performance and durable alkaline fuel cells and related technologies.
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Affiliation(s)
- Yao Yang
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Cheyenne R Peltier
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Rui Zeng
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Roberto Schimmenti
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Qihao Li
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Xin Huang
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States
| | - Zhifei Yan
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Georgia Potsi
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Ryan Selhorst
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Xinyao Lu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Weixuan Xu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Mariel Tader
- Department of Physics, Cornell University, Ithaca, New York 14853, United States
| | - Alexander V Soudackov
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Hanguang Zhang
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Mihail Krumov
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Ellen Murray
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Pengtao Xu
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Jeremy Hitt
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Linxi Xu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Hsin-Yu Ko
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Brian G Ernst
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Colin Bundschu
- Department of Physics, Cornell University, Ithaca, New York 14853, United States
| | - Aileen Luo
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Danielle Markovich
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States
| | - Meixue Hu
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Cheng He
- Chemical and Materials Science Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Hongsen Wang
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Jiye Fang
- Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
| | - Robert A DiStasio
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Lena F Kourkoutis
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States.,Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States
| | - Andrej Singer
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Kevin J T Noonan
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Li Xiao
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Lin Zhuang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Bryan S Pivovar
- Chemical and Materials Science Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Piotr Zelenay
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Enrique Herrero
- Instituto de Electroquímica, Universidad de Alicante, Alicante E-03080, Spain
| | - Juan M Feliu
- Instituto de Electroquímica, Universidad de Alicante, Alicante E-03080, Spain
| | - Jin Suntivich
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States.,Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States
| | - Emmanuel P Giannelis
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | | | - Tomás Arias
- Department of Physics, Cornell University, Ithaca, New York 14853, United States
| | - Manos Mavrikakis
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Thomas E Mallouk
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Joel D Brock
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States.,Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States
| | - Francis J DiSalvo
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Geoffrey W Coates
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Héctor D Abruña
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States.,Center for Alkaline Based Energy Solutions (CABES), Cornell University, Ithaca, New York 14853, United States
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5
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Winkler M, Schnierle M, Ehrlich F, Mehnert KI, Hunger D, Sheveleva AM, Burkhardt L, Bauer M, Tuna F, Ringenberg MR, van Slageren J. Electronic Structure of a Diiron Complex: A Multitechnique Experimental Study of [(dppf)Fe(CO) 3] +/0. Inorg Chem 2021; 60:2856-2865. [PMID: 33569942 DOI: 10.1021/acs.inorgchem.0c03259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Here we explore the electronic structure of the diiron complex [(dppf)Fe(CO)3]0/+ [10/+; dppf = 1,1'-bis(diphenylphosphino)ferrocene] in two oxidation states by an advanced multitechnique experimental approach. A combination of magnetic circular dichroism, X-ray absorption and emission, high-frequency electron paramagnetic resonance (EPR), and Mössbauer spectroscopies is used to establish that oxidation of 10 occurs on the carbonyl iron ion, resulting in a low-spin iron(I) ion. It is shown that an unequivocal result is obtained by combining several methods. Compound 1+ displays slow spin dynamics, which is used here to study its geometric structure by means of pulsed EPR methods. Surprisingly, these data show an association of the tetrakis[3,5-bis(trifluoromethylphenyl)]borate counterion with 1+.
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Affiliation(s)
- Mario Winkler
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - Marc Schnierle
- Institute of Inorganic Chemistry, University of Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - Felix Ehrlich
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - Kim-Isabelle Mehnert
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - David Hunger
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - Alena M Sheveleva
- Department of Chemistry and Photon Science Institute, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Lukas Burkhardt
- Department of Chemistry and Center for Sustainable Systems Design, Paderborn University, Warburger Strasse 100, Paderborn 33098, Germany
| | - Matthias Bauer
- Department of Chemistry and Center for Sustainable Systems Design, Paderborn University, Warburger Strasse 100, Paderborn 33098, Germany
| | - Floriana Tuna
- Department of Chemistry and Photon Science Institute, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Mark R Ringenberg
- Institute of Inorganic Chemistry, University of Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - Joris van Slageren
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
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6
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Chakraborty U, Bügel P, Fritsch L, Weigend F, Bauer M, Jacobi von Wangelin A. Planar Iron Hydride Nanoclusters: Combined Spectroscopic and Theoretical Insights into Structures and Building Principles. ChemistryOpen 2021; 10:265-271. [PMID: 33646644 PMCID: PMC7919527 DOI: 10.1002/open.202000307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 02/17/2021] [Indexed: 11/11/2022] Open
Abstract
The controlled assembly of well-defined planar nanoclusters from molecular precursors is synthetically challenging and often plagued by the predominant formation of 3D-structures and nanoparticles. Herein, we report planar iron hydride nanoclusters from reactions of main group element hydrides with iron(II) bis(hexamethyldisilazide). The structures and properties of isolated Fe4 , Fe6 , and Fe7 nanoplatelets and calculated intermediates enable an unprecedented insight into the underlying building principle and growth mechanism of iron clusters, metal monolayers, and nanoparticles.
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Affiliation(s)
- Uttam Chakraborty
- Dept. of ChemistryUniversity of Hamburg Martin Luther King Pl. 620146HamburgGermany
| | - Patrick Bügel
- Institut für NanotechnologieKarlsruher Institut für Technologie (KIT)v.-Helmholtz Pl. 176344Eggenstein-LeopoldshafenGermany
| | - Lorena Fritsch
- Dept. of Chemistry, Center for Sustainable Systems Design (CSSD)University of PaderbornWarburger Str. 10033098PaderbornGermany
| | - Florian Weigend
- Institut für NanotechnologieKarlsruher Institut für Technologie (KIT)v.-Helmholtz Pl. 176344Eggenstein-LeopoldshafenGermany
- Fachbereich ChemiePhilipps-Universität MarburgHans-Meerwein-Str. 435032MarburgGermany
| | - Matthias Bauer
- Dept. of Chemistry, Center for Sustainable Systems Design (CSSD)University of PaderbornWarburger Str. 10033098PaderbornGermany
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7
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Phu PN, Gutierrez CE, Kundu S, Sokaras D, Kroll T, Warren TH, Stieber SCE. Quantification of Ni-N-O Bond Angles and NO Activation by X-ray Emission Spectroscopy. Inorg Chem 2021; 60:736-744. [PMID: 33373520 DOI: 10.1021/acs.inorgchem.0c02724] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of β-diketiminate Ni-NO complexes with a range of NO binding modes and oxidation states were studied by X-ray emission spectroscopy (XES). The results demonstrate that XES can directly probe and distinguish end-on vs side-on NO coordination modes as well as one-electron NO reduction. Density functional theory (DFT) calculations show that the transition from the NO 2s2s σ* orbital has higher intensity for end-on NO coordination than for side-on NO coordination, whereas the 2s2s σ orbital has lower intensity. XES calculations in which the Ni-N-O bond angle was fixed over the range from 80° to 176° suggest that differences in NO coordination angles of ∼10° could be experimentally distinguished. Calculations of Cu nitrite reductase (NiR) demonstrate the utility of XES for characterizing NO intermediates in metalloenzymes. This work shows the capability of XES to distinguish NO coordination modes and oxidation states at Ni and highlights applications in quantifying small molecule activation in enzymes.
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Affiliation(s)
- Phan N Phu
- Department of Chemistry & Biochemistry, California State Polytechnic University, Pomona, California 91768, United States
| | - Carlos E Gutierrez
- Department of Chemistry & Biochemistry, California State Polytechnic University, Pomona, California 91768, United States
| | - Subrata Kundu
- Department of Chemistry, Georgetown University, Box 571227, Washington, D.C. 20057, United States.,School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Kerala 695551, India
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Timothy H Warren
- Department of Chemistry, Georgetown University, Box 571227, Washington, D.C. 20057, United States
| | - S Chantal E Stieber
- Department of Chemistry & Biochemistry, California State Polytechnic University, Pomona, California 91768, United States
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8
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Lim H, Baker ML, Cowley RE, Kim S, Bhadra M, Siegler MA, Kroll T, Sokaras D, Weng TC, Biswas DR, Dooley DM, Karlin KD, Hedman B, Hodgson KO, Solomon EI. Kβ X-ray Emission Spectroscopy as a Probe of Cu(I) Sites: Application to the Cu(I) Site in Preprocessed Galactose Oxidase. Inorg Chem 2020; 59:16567-16581. [PMID: 33136386 DOI: 10.1021/acs.inorgchem.0c02495] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cu(I) active sites in metalloproteins are involved in O2 activation, but their O2 reactivity is difficult to study due to the Cu(I) d10 closed shell which precludes the use of conventional spectroscopic methods. Kβ X-ray emission spectroscopy (XES) is a promising technique for investigating Cu(I) sites as it detects photons emitted by electronic transitions from occupied orbitals. Here, we demonstrate the utility of Kβ XES in probing Cu(I) sites in model complexes and a metalloprotein. Using Cu(I)Cl, emission features from double-ionization (DI) states are identified using varying incident X-ray photon energies, and a reasonable method to correct the data to remove DI contributions is presented. Kβ XES spectra of Cu(I) model complexes, having biologically relevant N/S ligands and different coordination numbers, are compared and analyzed, with the aid of density functional theory (DFT) calculations, to evaluate the sensitivity of the spectral features to the ligand environment. While the low-energy Kβ2,5 emission feature reflects the ionization energy of ligand np valence orbitals, the high-energy Kβ2,5 emission feature corresponds to transitions from molecular orbitals (MOs) having mainly Cu 3d character with the intensities determined by ligand-mediated d-p mixing. A Kβ XES spectrum of the Cu(I) site in preprocessed galactose oxidase (GOpre) supports the 1Tyr/2His structural model that was determined by our previous X-ray absorption spectroscopy and DFT study. The high-energy Kβ2,5 emission feature in the Cu(I)-GOpre data has information about the MO containing mostly Cu 3dx2-y2 character that is the frontier molecular orbital (FMO) for O2 activation, which shows the potential of Kβ XES in probing the Cu(I) FMO associated with small-molecule activation in metalloproteins.
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Affiliation(s)
- Hyeongtaek Lim
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Michael L Baker
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Ryan E Cowley
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Sunghee Kim
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Mayukh Bhadra
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Maxime A Siegler
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Tsu-Chien Weng
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Dalia R Biswas
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - David M Dooley
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States.,University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Kenneth D Karlin
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Britt Hedman
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Keith O Hodgson
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
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9
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Chen WT, Hsu CW, Lee JF, Pao CW, Hsu IJ. Theoretical Analysis of Fe K-Edge XANES on Iron Pentacarbonyl. ACS OMEGA 2020; 5:4991-5000. [PMID: 32201785 PMCID: PMC7081404 DOI: 10.1021/acsomega.9b03887] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 02/21/2020] [Indexed: 05/21/2023]
Abstract
Iron pentacarbonyl (Fe(CO)5) is a versatile material that is utilized as an inhibitor of flame, shows soot suppressibility, and is used as a precursor for focused electron-beam-induced deposition (FEBID). X-ray absorption near-edge structure (XANES) of the K edge, which is a powerful technique for monitoring the oxidation states and coordination environment of metal sites, can be used to gain insight into Fe(CO)5-related reaction mechanisms in in situ experiments. We use a finite difference method (FDM) and molecular-orbital-based time-dependent density functional theory (TDDFT) calculations to clarify the Fe K-edge XANES features of Fe(CO)5. The two pre-edge peaks P1 and P2 are mainly the Fe(1s) → Fe-C(σ*) and Fe(1s) → Fe-C(π*) transitions, respectively. When the geometry transformed from D 3h to C 4v symmetry, a ∼30% decrease of the pre-edge P2 intensity was observed in the simulated spectra. This implies that the π bonding of Fe and CO is sensitive to changes in geometry. The following rising edge and white line regions are assigned to the Fe(1s) → Fe(4p)(mixing C(2p)) transitions. Our results may provide useful information to interpret XANES spectra variations of in situ reactions of metal-CO or similar compounds with π acceptor ligandlike metal-CN complexes.
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Affiliation(s)
- Wei-Ting Chen
- Department
of Molecular Science and Engineering, National
Taipei University of Technology, Taipei 10608, Taiwan
| | - Che-Wei Hsu
- Department
of Molecular Science and Engineering, National
Taipei University of Technology, Taipei 10608, Taiwan
| | - Jyh-Fu Lee
- National
Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Chih-Wen Pao
- National
Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - I-Jui Hsu
- Department
of Molecular Science and Engineering, National
Taipei University of Technology, Taipei 10608, Taiwan
- Research
and Development Center for Smart Textile Technology, National Taipei University of Technology, Taipei 10608, Taiwan
- E-mail: .
Tel: +886-2-27712171#2420
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10
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Burkhardt L, Vukadinovic Y, Nowakowski M, Kalinko A, Rudolph J, Carlsson PA, Jacob CR, Bauer M. Electronic Structure of the Hieber Anion [Fe(CO) 3(NO)] - Revisited by X-ray Emission and Absorption Spectroscopy. Inorg Chem 2020; 59:3551-3561. [PMID: 32125149 DOI: 10.1021/acs.inorgchem.9b02092] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
While the Hieber anion [Fe(CO)3(NO)]- has been reincarnated in the last years as an active catalyst in organic synthesis, there is still a debate about the oxidation state of the central Fe atom and the resulting charge of the NO ligand. To shed new light on this question and to understand the Fe-NO interaction in the Hieber anion, it is investigated in comparison to the formal 3d8 reference Fe(CO)5 and the formal 3d10 reference [Fe(CO)4]2- by the combination of valence-to-core X-ray emission spectroscopy (VtC-XES), X-ray absorption near-edge structure spectroscopy (XANES), and high-energy-resolution fluorescence-detected XANES. In order to extract information about the electronic structure, time-dependent density functional theory and ground-state density functional theory calculations are applied. This combination of experimental and computational methods reveals that the electron density at the Fe center of the Hieber resembles that of the isoelectronic [Fe(CO)4]2-. These observations challenge recent descriptions of the Hieber anion and reopen the debate about the experimentally and computationally determined Fe oxidation state and charge on the NO ligand.
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Affiliation(s)
- Lukas Burkhardt
- Department of Chemistry and Center for Sustainable Systems Design, Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
| | - Yannik Vukadinovic
- Department of Chemistry and Center for Sustainable Systems Design, Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
| | - Michał Nowakowski
- Department of Chemistry and Center for Sustainable Systems Design, Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
| | - Aleksandr Kalinko
- Department of Chemistry and Center for Sustainable Systems Design, Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
| | - Julian Rudolph
- Institute of Physical and Theoretical Chemistry, Technische Universität Braunschweig, Gaußstraße 17, 38106 Braunschweig, Germany
| | - Per-Anders Carlsson
- Department of Chemistry and Chemical Engineering and Competence Centre for Catalysis, Chalmers University of Technology, 41296 Gothenburg, Sweden
| | - Christoph R Jacob
- Institute of Physical and Theoretical Chemistry, Technische Universität Braunschweig, Gaußstraße 17, 38106 Braunschweig, Germany
| | - Matthias Bauer
- Department of Chemistry and Center for Sustainable Systems Design, Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
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11
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Schoch A, Burkhardt L, Schoch R, Stührenberg K, Bauer M. Hard X-ray spectroscopy: an exhaustive toolbox for mechanistic studies (?). Faraday Discuss 2020; 220:113-132. [PMID: 31532420 DOI: 10.1039/c9fd00070d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Established and recent hard X-ray spectroscopic methods in the form of conventional X-ray absorption near edge structure spectroscopy (XANES) and extended X-ray absorption fine structure spectroscopy (EXAFS), and the photon-in/photon-out techniques high energy resolution fluorescence detection XANES and valence-to-core X-ray emission spectroscopy (VtC-XES) provide unique opportunities to study mechanisms in metal-organic reactions. The combination of these techniques allows the determination of the local geometric and electronic structures in the form of the numbers of nearest neighbours, their types and distances around an X-ray absorbing atom and the highest occupied and lowest unoccupied molecular levels. Different sample cells for this purpose, which allow high pressure, electrochemical or multi-spectroscopic measurements under inert conditions, are presented and discussed. The potential of HERFD-XANES and VtC-XES to eliminate limitations of conventional EXAFS spectroscopy is established with case studies on the Hieber anion [Fe(CO)3(NO)]- and the iron hydride complex [Fe(CO)H(NO)(PPh3)2]. With VtC-XES the formation of an allyl complex by reaction of [Fe(CO)3(NO)]- in a catalytic nucleophilic substitution reaction can be followed. Combination of HERFD-XANES and VtC-XES allows the identification and investigation of hydride species, as well as their fate in chemical reactions. On the other hand, in order to investigate the active species formation in iron-catalysed cross coupling reactions, conventional XANES and EXAFS are the method of choice for the moment. For all examples, the advantages and limitations of the hard X-ray toolbox are commented on and the value of the individual methods are compared.
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Affiliation(s)
- Anke Schoch
- Paderborn University, Department of Chemistry, Warburger Str. 100, 33098 Paderborn, Germany.
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12
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Kalinko A, Caliebe WA, Schoch R, Bauer M. A von Hamos-type hard X-ray spectrometer at the PETRA III beamline P64. JOURNAL OF SYNCHROTRON RADIATION 2020; 27:31-36. [PMID: 31868733 PMCID: PMC6927517 DOI: 10.1107/s1600577519013638] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 10/05/2019] [Indexed: 05/20/2023]
Abstract
The design and performance of the high-resolution wavelength-dispersive multi-crystal von Hamos-type spectrometer at PETRA III beamline P64 are described. Extended analyzer crystal collection available at the beamline allows coverage of a broad energy range from 5 keV to 20 keV with an energy resolution of 0.35-1 eV. Particular attention was paid to enabling two-color measurements by a combination of two types of analyzer crystals and two two-dimensional detectors. The performance of the spectrometer is demonstrated by elastic-line and emission-line measurements on various compounds.
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Affiliation(s)
- Aleksandr Kalinko
- Department Chemie and Center for Sustainable Systems Design (CSSD), Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
- Photon Science DESY, Notkestraße 85, 22607 Hamburg, Germany
- Correspondence e-mail:
| | | | - Roland Schoch
- Department Chemie and Center for Sustainable Systems Design (CSSD), Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - Matthias Bauer
- Department Chemie and Center for Sustainable Systems Design (CSSD), Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
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13
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Bergmann TG, Welzel MO, Jacob CR. Towards theoretical spectroscopy with error bars: systematic quantification of the structural sensitivity of calculated spectra. Chem Sci 2019; 11:1862-1877. [PMID: 34123280 PMCID: PMC8148348 DOI: 10.1039/c9sc05103a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Molecular spectra calculated with quantum-chemical methods are subject to a number of uncertainties (e.g., errors introduced by the computational methodology) that hamper the direct comparison of experiment and computation. Judging these uncertainties is crucial for drawing reliable conclusions from the interplay of experimental and theoretical spectroscopy, but largely relies on subjective judgment. Here, we explore the application of methods from uncertainty quantification to theoretical spectroscopy, with the ultimate goal of providing systematic error bars for calculated spectra. As a first target, we consider distortions of the underlying molecular structure as one important source of uncertainty. We show that by performing a principal component analysis, the most influential collective distortions can be identified, which allows for the construction of surrogate models that are amenable to a statistical analysis of the propagation of uncertainties in the molecular structure to uncertainties in the calculated spectrum. This is applied to the calculation of X-ray emission spectra of iron carbonyl complexes, of the electronic excitation spectrum of a coumarin dye, and of the infrared spectrum of alanine. We show that with our approach it becomes possible to obtain error bars for calculated spectra that account for uncertainties in the molecular structure. This is an important first step towards systematically quantifying other relevant sources of uncertainty in theoretical spectroscopy. Uncertainty quantification is applied in theoretical spectroscopy to obtain error bars accounting for the structural sensitivity of calculated spectra.![]()
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Affiliation(s)
- Tobias G Bergmann
- Technische Universität Braunschweig, Institute of Physical and Theoretical Chemistry Gaußstraße 17 38106 Braunschweig Germany
| | - Michael O Welzel
- Technische Universität Braunschweig, Institute of Physical and Theoretical Chemistry Gaußstraße 17 38106 Braunschweig Germany
| | - Christoph R Jacob
- Technische Universität Braunschweig, Institute of Physical and Theoretical Chemistry Gaußstraße 17 38106 Braunschweig Germany
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14
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Matson BD, McLoughlin EA, Armstrong KC, Waymouth RM, Sarangi R. Effect of Redox Active Ligands on the Electrochemical Properties of Manganese Tricarbonyl Complexes. Inorg Chem 2019; 58:7453-7465. [PMID: 31117629 DOI: 10.1021/acs.inorgchem.9b00652] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The synthesis, structural characterization, and electrochemical behavior of the neutral Mn(azpy)(CO)3(Br) 4 (azpy = 2-phenylazopyridine) complex is reported and compared with its structural analogue Mn(bipy)(CO)3(Br) 1 (bipy = 2,2'-bipyridine). 4 exhibits reversible two-electron reduction at a mild potential (-0.93 V vs Fc+/0 in acetonitrile) in contrast to 1, which exhibits two sequential one-electron reductions at -1.68 V and -1.89 V vs Fc+/0 in acetonitrile. The key electronic structure differences between 1 and 4 that lead to disparate electrochemical properties are investigated using a combination of Mn-K-edge X-ray absorption spectroscopy (XAS), Mn-Kβ X-ray emission spectroscopy (XES), and density functional theory (DFT) on 1, 4, their debrominated analogues, [Mn(L)(CO)3(CH3CN)][CF3SO3] (L = bipy 2, azpy 5), and two-electron reduced counterparts [Mn(bipy)(CO)3][K(18-crown-6)] 3 and [Mn(azpy)(CO)3][Cp2Co] 6. The results reveal differences in the distribution of electrons about the CO and bidentate ligands (bipy and azpy), particularly upon formation of the highly reduced, formally Mn(-1) species. The data show that the degree of ligand noninnocence and resulting redox-activity in Mn(L)(CO)3 type complexes impacts not only the reducing power of such systems, but the speciation of the reduced complexes via perturbation of the monomer-dimer equilibrium in the singly reduced Mn(0) state. This study highlights the role of redox-active ligands in tuning the reactivity of metal centers involved in electrocatalytic transformations.
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Affiliation(s)
- Benjamin D Matson
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States.,Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , Menlo Park , California , United States
| | - Elizabeth A McLoughlin
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Keith C Armstrong
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Robert M Waymouth
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Ritimukta Sarangi
- Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , Menlo Park , California , United States
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15
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Burkhardt L, Mueller C, Groß OA, Sun Y, Sitzmann H, Bauer M. The Bonding Situation in the Dinuclear Tetra-Hydrido Complex [{ 5CpFe} 2(μ-H) 4] Revisited by Hard X-Ray Spectroscopy. Inorg Chem 2019; 58:6609-6618. [PMID: 30596494 DOI: 10.1021/acs.inorgchem.8b03032] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
High energy resolution fluorescence detected XANES (HERFD-XANES) and valence-to-core X-ray emission spectroscopy (VtC-XES) are introduced as powerful tools to investigate hydride-iron interaction, the possible iron-iron bond, and iron spin state of the dinuclear tetra-hydrido complex [{5CpFe}2(μ-H)4] (1H, 5Cp = η5-C5 iPr5) by thoroughly accessing the geometric and electronic structure of this complex in comparison to the nonhydride reference [5CpCpFe] (1, Cp = C5H5). The so far observed most intense hydride induced signals in the pre-edge feature of the HERFD-XANES and in the VtC-XES spectra at the iron K-edge allow a precise analysis of the LUMO and HOMO states, respectively, by application of time-dependent density function theory (TD-DFT) and density functional theory (DFT) calculations. The results of these calculations are further employed to understand the oxidation state, spin states, and potential Fe-Fe bonds in this complex.
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Affiliation(s)
- Lukas Burkhardt
- Faculty of Science , Paderborn University , Warburger Straße 100 , 33098 Paderborn , Germany
| | - Carsten Mueller
- Department of Chemistry , University of Kaiserslautern , Erwin-Schrödinger-Straße 54 , 67663 Kaiserslautern , Germany
| | - Oliver A Groß
- Faculty of Science , Paderborn University , Warburger Straße 100 , 33098 Paderborn , Germany
| | - Yu Sun
- Department of Chemistry , University of Kaiserslautern , Erwin-Schrödinger-Straße 54 , 67663 Kaiserslautern , Germany
| | - Helmut Sitzmann
- Department of Chemistry , University of Kaiserslautern , Erwin-Schrödinger-Straße 54 , 67663 Kaiserslautern , Germany
| | - Matthias Bauer
- Faculty of Science , Paderborn University , Warburger Straße 100 , 33098 Paderborn , Germany.,Center for Sustainable Systems Design (CSSD) , Paderborn University , Warburger Straße 100 , 33098 Paderborn , Germany
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