1
|
Boro B, Paul R, Tan HL, Trinh QT, Rabeah J, Chang CC, Pao CW, Liu W, Nguyen NT, Mai BK, Mondal J. Experimental Validation and Computational Predictions Join Forces to Map Catalytic C-H Activation in Ferrocene Metalated Porous Organic Polymers. ACS APPLIED MATERIALS & INTERFACES 2023; 15:21027-21039. [PMID: 37083336 DOI: 10.1021/acsami.3c01393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
In recent times, a self-complementary balanced characteristic feature with the combination of both covalent bonds (structural stability) and open metal sites (single-site catalysis) introduced an advanced emerging functional nanoarchitecture termed metalated porous organic polymers (M-POPs). However, the development of M-POPs in view of the current interest in catalysis has been realized still in its infancy and remains a challenge for the years to come. In this work, we built benzothiazole-linked Fe-metalated porous organic polymer (Fc-Bz-POP) using ferrocene dicarboxaldehyde (FDC), 1,3,5-tris(4-aminophenyl) benzene (APB), and elemental sulfur (S8) via a template-free, multicomponent, cost-effective one-pot synthetic approach. This Fc-Bz-POP is endowed with unique features including an extended network unit, isolated active sites, and catalytic pocket with a possible local structure, in which convergent binding sites are positioned in such a way that substrate molecules can be held in close proximity. Prospective catalytic application of this Fc-Bz-POP has been explored in executing catalytic allylic "C-H" bond functionalization of cyclohexene (CHX) in water at room temperature. Catalytic screening results identified that a superior performance with a CHX conversion of 95% and a 2-cyclohexene-1-ol selectivity (COL) of 80.8% at 4 h and 25 °C temperature has been achieved over Fc-Bz-POP, thereby addressing previous shortcomings of the other conventional catalytic systems. Comprehensive characterization understanding with the aid of synchrotron-based extended X-ray absorption fine structure (EXAFS) analysis manifested that the Fe atom with an oxidation state of +2 in our Fc-Bz-POP catalytic system encompasses a sandwich structural environment with the two symmetrical eclipsed cyclopentadienyl (Cp) rings, featuring nearest-neighbor (NN) Fe-C (≈2.05 Å) intramolecular bonds, as validated by the Fe L3-edge EXAFS fitting result. Furthermore, in situ attenuated total reflection-infrared spectroscopy (ATR-IR) analysis data for liquid-phase oxidation of cyclohexene allow for the formulation of a molecular-level reaction mechanistic pathway with the involvement of specific reaction intermediates, which is initiated by the radical functionalization of the allyl hydrogen. A deep insight investigation from density functional theory (DFT) calculations unambiguously revealed that the dominant pathway from cyclohexene to 2-cyclohexene-1-ol is initiated by an allyl-H functionalization step accompanied by the formation of 2-cyclohexene-1-hydroperoxide species as the key reaction intermediate. Electronic properties obtained from DFT simulations via the charge density difference plot, Bader charge, and density of state (DOS) demonstrate the importance of the organic polymer frame structure in altering the electronic properties of the Fe site in Fc-Bz-POP, resulting in its high activity. Our contribution has great implications for the precise design of metalated porous organic polymer-based robust catalysts, which will open a new avenue to get a clear image of surface catalysis.
Collapse
Affiliation(s)
- Bishal Boro
- Department of Catalysis & Fine Chemicals, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Ratul Paul
- Department of Catalysis & Fine Chemicals, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Hui Ling Tan
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Avenue, Singapore 637459, Singapore
| | - Quang Thang Trinh
- Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, Queensland 4111, Australia
| | - Jabor Rabeah
- Leibniz Institute for Catalysis (LIKAT Rostock), Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Chia-Che Chang
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu 30076, Taiwan
| | - Chih-Wen Pao
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu 30076, Taiwan
| | - Wen Liu
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Avenue, Singapore 637459, Singapore
| | - Nam-Trung Nguyen
- Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, Queensland 4111, Australia
| | - Binh Khanh Mai
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - John Mondal
- Department of Catalysis & Fine Chemicals, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| |
Collapse
|
2
|
Yang M, Sissay A, Chen M, Lopata K. Intruder Peak-Free Transient Inner-Shell Spectra Using Real-Time Simulations. J Chem Theory Comput 2022; 18:992-1002. [PMID: 35025498 DOI: 10.1021/acs.jctc.1c00079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Real-time methods are convenient for simulating core-level absorption spectra but suffer from nonphysical intruder peaks when using atom-centered basis sets. In transient absorption spectra, these peaks exhibit highly nonphysical time-dependent modulations in their energies and oscillator strengths. In this paper, we address the origins of these intruder peaks and propose a straightforward and effective solution based on a filtered dipole operator. In combination with real-time time-dependent density functional theory (RT-TDDFT), we demonstrate how to compute intruder-free attosecond transient X-ray absorption spectra for the aminophenol (C6H7NO) oxygen and nitrogen K-edges and the α-quartz (SiO2) silicon L-edge. Without filtering, the computed spectra are qualitatively wrong. This procedure is suitable for both static and transient inner-shell spectroscopy studies and can easily be implemented in a range of real-time methodologies.
Collapse
Affiliation(s)
- Mengqi Yang
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Adonay Sissay
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Min Chen
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Kenneth Lopata
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States.,Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| |
Collapse
|
3
|
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.
Collapse
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
| | | |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
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: 10] [Impact Index Per Article: 2.5] [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.
Collapse
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
| |
Collapse
|
6
|
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] [Grants] [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.
Collapse
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
| | | | - 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
| |
Collapse
|
7
|
Späth A. Additive Nano-Lithography with Focused Soft X-rays: Basics, Challenges, and Opportunities. MICROMACHINES 2019; 10:E834. [PMID: 31801198 PMCID: PMC6953100 DOI: 10.3390/mi10120834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 11/27/2019] [Accepted: 11/29/2019] [Indexed: 12/18/2022]
Abstract
Focused soft X-ray beam induced deposition (FXBID) is a novel technique for direct-write nanofabrication of metallic nanostructures from metal organic precursor gases. It combines the established concepts of focused electron beam induced processing (FEBIP) and X-ray lithography (XRL). The present setup is based on a scanning transmission X-ray microscope (STXM) equipped with a gas flow cell to provide metal organic precursor molecules towards the intended deposition zone. Fundamentals of X-ray microscopy instrumentation and X-ray radiation chemistry relevant for FXBID development are presented in a comprehensive form. Recently published proof-of-concept studies on initial experiments on FXBID nanolithography are reviewed for an overview on current progress and proposed advances of nanofabrication performance. Potential applications and advantages of FXBID are discussed with respect to competing electron/ion based techniques.
Collapse
Affiliation(s)
- Andreas Späth
- Friedrich-Alexander-University Erlangen-Nuremberg, Physical Chemistry II, Egerlandstraße 3, 91058 Erlangen, Germany
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Carlotto S, Finetti P, de Simone M, Coreno M, Casella G, Sambi M, Casarin M. Comparative Experimental and Theoretical Study of the Fe L 2,3-Edges X-ray Absorption Spectroscopy in Three Highly Popular, Low-Spin Organoiron Complexes: [Fe(CO) 5], [(η 5-C 5H 5)Fe(CO)(μ-CO)] 2, and [(η 5-C 5H 5) 2Fe]. Inorg Chem 2019; 58:5844-5857. [PMID: 30998004 DOI: 10.1021/acs.inorgchem.9b00226] [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 occupied and unoccupied electronic structures of three highly popular, closed shell organoiron complexes ([Fe(CO)5], [(η5-C5H5)Fe(CO)(μ-CO)]2, and [(η5-C5H5)2Fe]) have been theoretically investigated by taking advantage of density functional theory (DFT) calculations coupled to the isolobal analogy ( Elian et al. Inorg. Chem. 1976 , 15 , 1148 ). The adopted approach allowed us to look into the relative role played by the ligand → Fe donation and the Fe → ligand back-donation in title molecules, as well as to investigate how CO- (terminal or bridging) and [(η5-C5H5)]--based π* orbitals compete when these two ligands are simultaneously present as in [(η5-C5H5)Fe(CO)(μ-CO)]2. Insights into the nature and the strength of the bonding between Fe and the C donor atoms have been gained by exploiting the Nalewajski-Mrozek bond multiplicity index ( Nalewajski et al. Int. J. Quantum Chem. 1994 , 51 , 187 ), which have been found especially sensitive even to tiny bond distance variations. The bonding picture emerging from ground state DFT results proved fruitful to guide the assignment of original, high-resolution, gas-phase L2,3-edges X-ray absorption spectra of the title molecules, which have been modeled by the two-component relativistic time-dependent DFT including spin orbit coupling and correlation effects and taking advantage of the full use of symmetry. Assignments alternative to those reported in the literature for both [Fe(CO)5] and [(η5-C5H5)2Fe] are herein proposed. Despite the high popularity of the investigated molecules, the complementary use of symmetry, orbital, and spectroscopy allowed us to further look into the metal-ligand symmetry-restricted-covalency and the differential-orbital covalency, which characterize them.
Collapse
Affiliation(s)
- Silvia Carlotto
- Dipartimento di Scienze Chimiche , Università degli Studi di Padova , Via Francesco Marzolo 1 , 35131 Padova , Italy
| | - Paola Finetti
- Dipartimento di Scienze e Metodi dell'Ingegneria , Università di Modena , Via Università 4 , 41121 Modena , Italy
| | | | | | - Girolamo Casella
- Dipartimento di Scienze della Terra e del Mare , Università degli Studi di Palermo , Via Archirafi 22 , 90123 Palermo , Italy
| | - Mauro Sambi
- Dipartimento di Scienze Chimiche , Università degli Studi di Padova , Via Francesco Marzolo 1 , 35131 Padova , Italy
| | - Maurizio Casarin
- Dipartimento di Scienze Chimiche , Università degli Studi di Padova , Via Francesco Marzolo 1 , 35131 Padova , Italy.,CNR - ICMATE , Via Francesco Marzolo 1 , 35131 Padova , Italy
| |
Collapse
|
10
|
Rudolph J, Jacob CR. Revisiting the Dependence of Cu K-Edge X-ray Absorption Spectra on Oxidation State and Coordination Environment. Inorg Chem 2018; 57:10591-10607. [PMID: 30113840 DOI: 10.1021/acs.inorgchem.8b01219] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
X-ray absorption spectroscopy (XAS) at the Cu K-edge is an important tool for probing the properties of copper centers in transition-metal chemistry and catalysis. However, the interpretation of experimental XAS spectra requires a detailed understanding of the dependence of spectroscopic features on the local geometric and electronic structure, which can be established by theoretical X-ray spectroscopy. Here, we present a systematic computational study of the Cu K-edge XAS spectra of selected Cu complexes based on time-dependent density-functional theory in combination with a molecular orbital analysis of the relevant transitions. For a series of Cu ammine model complexes as well as a comprehensive test set of 12 Cu(I) and 5 Cu(II) complexes, we revisit the dependence of the pre-edge region in Cu K-edge XAS spectra on oxidation state and coordination geometry. While our calculations confirm earlier experimental assignments, we can also reveal additional signatures of the ligand orbitals and identify the underlying orbital interactions. The comprehensive picture revealed by this study will provide a reliable basis for the interpretation of in situ Cu K-edge XAS spectra of catalytic intermediates.
Collapse
Affiliation(s)
- Julian Rudolph
- Institute of Physical and Theoretical Chemistry , TU Braunschweig , Gaußstraße 17 , 38106 Braunschweig , Germany
| | - Christoph R Jacob
- Institute of Physical and Theoretical Chemistry , TU Braunschweig , Gaußstraße 17 , 38106 Braunschweig , Germany
| |
Collapse
|
11
|
Goodwin CAP, Réant BLL, Kragskow JGC, DiMucci IM, Lancaster KM, Mills DP, Sproules S. Heteroleptic samarium(iii) halide complexes probed by fluorescence-detected L 3-edge X-ray absorption spectroscopy. Dalton Trans 2018; 47:10613-10625. [PMID: 29790545 PMCID: PMC6083822 DOI: 10.1039/c8dt01452c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The novel series of heteroleptic Sm(iii) halide complexes provides the backdrop for a fluorescence-detected Lα1 X-ray absorption spectroscopic study.
The addition of various oxidants to the near-linear Sm(ii) complex [Sm(N††)2] (1), where N†† is the bulky bis(triisopropylsilyl)amide ligand {N(SiiPr3)2}, afforded a family of heteroleptic three-coordinate Sm(iii) halide complexes, [Sm(N††)2(X)] (X = F, 2-F; Cl, 2-Cl; Br, 2-Br; I, 2-I). In addition, the trinuclear cluster [{Sm(N††)}3(μ2-I)3(μ3-I)2] (3), which formally contains one Sm(ii) and two Sm(iii) centres, was isolated during the synthesis of 2-I. Complexes 2-X are remarkably stable towards ligand redistribution, which is often a facile process for heteroleptic complexes of smaller monodentate ligands in lanthanide chemistry, including the related bis(trimethylsilyl)amide {N(SiMe3)2} (N′′). Complexes 2-X and 3 have been characterised by single crystal X-ray diffraction, elemental analysis, multinuclear NMR, FTIR and electronic spectroscopy. The Lα1 fluorescence-detected X-ray absorption spectra recorded at the Sm L3-edge for 2-X exhibited a resolved pre-edge peak defined as an envelope of quadrupole-allowed 2p → 4f transitions. The X-ray absorption spectral features were successfully reproduced using time-dependent density functional theoretical (TD-DFT) calculations that synergistically support the experimental observations as well as the theoretical model upon which the electronic structure and bonding in these lanthanide complexes is derived.
Collapse
Affiliation(s)
- Conrad A P Goodwin
- School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Benjamin L L Réant
- School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Jon G C Kragskow
- School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Ida M DiMucci
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York, 14853, USA.
| | - Kyle M Lancaster
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York, 14853, USA.
| | - David P Mills
- School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Stephen Sproules
- WestCHEM, School of Chemistry, The University of Glasgow, Glasgow G12 8QQ, UK.
| |
Collapse
|
12
|
Kubas A, Maszota P. Theoretical Insights into the Unique Ligation of [Fe
4
S
4
] Iron–Sulfur Clusters. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Adam Kubas
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01‐224 Warsaw Poland
| | - Paweł Maszota
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01‐224 Warsaw Poland
| |
Collapse
|
13
|
Ismail I, Guillemin R, Marchenko T, Travnikova O, Ablett JM, Rueff JP, Piancastelli MN, Simon M, Journel L. Experimental setup for the study of resonant inelastic X-ray scattering of organometallic complexes in gas phase. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:063107. [PMID: 29960531 DOI: 10.1063/1.5021536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A new setup has been designed and built to study organometallic complexes in gas phase at the third-generation Synchrotron radiation sources. This setup consists of a new homemade computer-controlled gas cell that allows us to sublimate solid samples by accurately controlling the temperature. This cell has been developed to be a part of the high-resolution X-ray emission spectrometer permanently installed at the GALAXIES beamline of the French National Synchrotron Facility SOLEIL. To illustrate the capabilities of the setup, the cell has been successfully used to record high-resolution Kα emission spectra of gas-phase ferrocene Fe(C5H5)2 and to characterize their dependence with the excitation energy. This will allow to extend resonant X-ray emission to different organometallic molecules.
Collapse
Affiliation(s)
- I Ismail
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 75005 Paris Cedex 05, France
| | - R Guillemin
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 75005 Paris Cedex 05, France
| | - T Marchenko
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 75005 Paris Cedex 05, France
| | - O Travnikova
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 75005 Paris Cedex 05, France
| | - J M Ablett
- Synchrotron SOLEIL, l'Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex, France
| | - J-P Rueff
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 75005 Paris Cedex 05, France
| | - M-N Piancastelli
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 75005 Paris Cedex 05, France
| | - M Simon
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 75005 Paris Cedex 05, France
| | - L Journel
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 75005 Paris Cedex 05, France
| |
Collapse
|
14
|
Atkins AJ, Talotta F, Freitag L, Boggio-Pasqua M, González L. Assessing Excited State Energy Gaps with Time-Dependent Density Functional Theory on Ru(II) Complexes. J Chem Theory Comput 2017; 13:4123-4145. [DOI: 10.1021/acs.jctc.7b00379] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Andrew J. Atkins
- Institute
of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
| | - Francesco Talotta
- Institute
of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
- Laboratoire de
Chimie et Physique Quantiques (UMR5626), CNRS et Université
de Toulouse 3, 31062 Toulouse, France
| | - Leon Freitag
- Institute
of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
| | - Martial Boggio-Pasqua
- Laboratoire de
Chimie et Physique Quantiques (UMR5626), CNRS et Université
de Toulouse 3, 31062 Toulouse, France
| | - Leticia González
- Institute
of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
| |
Collapse
|
15
|
List NH, Saue T, Norman P. Rotationally averaged linear absorption spectra beyond the electric-dipole approximation. Mol Phys 2016. [DOI: 10.1080/00268976.2016.1187773] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Nanna Holmgaard List
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden
| | - Trond Saue
- Laboratoire de Chimie et Physique Quantiques, UMR 5626 — CNRS/Université Toulouse III (Paul Sabatier), 31062 Toulouse Cedex 09, France
| | - Patrick Norman
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden
| |
Collapse
|
16
|
Wenzel J, Wormit M, Dreuw A. Calculating X-ray Absorption Spectra of Open-Shell Molecules with the Unrestricted Algebraic-Diagrammatic Construction Scheme for the Polarization Propagator. J Chem Theory Comput 2015; 10:4583-98. [PMID: 26588152 DOI: 10.1021/ct5006888] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
X-ray absorption spectroscopy (XAS) is a powerful tool that provides information about the electronic structure of molecules via excitation of electrons from the K-shell core region to the unoccupied molecular levels. These high-lying electronic core-excited states can be accurately calculated using the algebraic-diagrammatic construction scheme of second order ADC(2) by applying the core-valence separation (CVS) approximation to the ADC(2) working equations. For the first time, an efficient implementation of an unrestricted CVS-ADC(2) variant CVS-UADC(2) is presented for the calculation of open-shell molecules by treating α and β spins separately from each other. The potential of the CVS-UADC(2) method is demonstrated with a set of small organic radicals by comparison with standard TD-DFT/B3LYP values and experimental data. It turns out that the extended variant CVS-UADC(2)-x, in particular, provides the most accurate results with errors of only 0.1% compared to experimental values. This remarkable agreement justifies the prediction of yet nonrecorded experimental XAS spectra like the one of the anthracene cation. The cation exhibits additional peaks due to the half-filled single-occupied molecular orbital, which may help to distinguish cation from the neutral species.
Collapse
Affiliation(s)
- Jan Wenzel
- Interdisciplinary Center for Scientific Computing, University of Heidelberg , Im Neuenheimer Feld 368, 69120 Heidelberg, Germany
| | - Michael Wormit
- Interdisciplinary Center for Scientific Computing, University of Heidelberg , Im Neuenheimer Feld 368, 69120 Heidelberg, Germany
| | - Andreas Dreuw
- Interdisciplinary Center for Scientific Computing, University of Heidelberg , Im Neuenheimer Feld 368, 69120 Heidelberg, Germany
| |
Collapse
|
17
|
Martin-Diaconescu V, Gennari M, Gerey B, Tsui E, Kanady J, Tran R, Pécaut J, Maganas D, Krewald V, Gouré E, Duboc C, Yano J, Agapie T, Collomb MN, DeBeer S. Ca K-edge XAS as a probe of calcium centers in complex systems. Inorg Chem 2015; 54:1283-92. [PMID: 25492398 PMCID: PMC4331723 DOI: 10.1021/ic501991e] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Indexed: 12/21/2022]
Abstract
Herein, Ca K-edge X-ray absorption spectroscopy (XAS) is developed as a means to characterize the local environment of calcium centers. The spectra for six, seven, and eight coordinate inorganic and molecular calcium complexes were analyzed and determined to be primarily influenced by the coordination environment and site symmetry at the calcium center. The experimental results are closely correlated to time-dependent density functional theory (TD-DFT) calculations of the XAS spectra. The applicability of this methodology to complex systems was investigated using structural mimics of the oxygen-evolving complex (OEC) of PSII. It was found that Ca K-edge XAS is a sensitive probe for structural changes occurring in the cubane heterometallic cluster due to Mn oxidation. Future applications to the OEC are discussed.
Collapse
Affiliation(s)
- Vlad Martin-Diaconescu
- Max Planck Institute
for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Marcello Gennari
- Univ. Grenoble Alpes, DCM and
CNRS, DCM, F-38000 Grenoble, France
| | - Bertrand Gerey
- Univ. Grenoble Alpes, DCM and
CNRS, DCM, F-38000 Grenoble, France
| | - Emily Tsui
- California Institute of
Technology, Department of Chemistry, Pasadena, California 91125, United States
| | - Jacob Kanady
- California Institute of
Technology, Department of Chemistry, Pasadena, California 91125, United States
| | - Rosalie Tran
- Lawrence Berkeley National Laboratory − Physical Biosciences Division, Berkeley, California 94720, United States
| | - Jacques Pécaut
- Laboratoire de Reconnaissance Ionique
et Chimie de Coordination (LCIB, SCIB, INAC, CEA Grenoble), 38054 Grenoble
Cedex 9, France
| | - Dimitrios Maganas
- Max Planck Institute
for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Vera Krewald
- Max Planck Institute
for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Eric Gouré
- Univ. Grenoble Alpes, DCM and
CNRS, DCM, F-38000 Grenoble, France
| | - Carole Duboc
- Univ. Grenoble Alpes, DCM and
CNRS, DCM, F-38000 Grenoble, France
| | - Junko Yano
- Lawrence Berkeley National Laboratory − Physical Biosciences Division, Berkeley, California 94720, United States
| | - Theodor Agapie
- California Institute of
Technology, Department of Chemistry, Pasadena, California 91125, United States
| | | | - Serena DeBeer
- Max Planck Institute
for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
- Department of Chemistry and Chemical
Biology, Cornell University, Ithaca, New York 14853, United States
| |
Collapse
|
18
|
Preise 2014 der Grupo Especializado de Química Organometálica: J. Lloret-Fillol, E. Fernández und J. Forniés / Hans-G.-A.-Hellmann-Preis: C. Jacob. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201411215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
19
|
Islam S, Wang F. The d-electrons of Fe in ferrocene: the excess orbital energy spectrum (EOES). RSC Adv 2015. [DOI: 10.1039/c4ra14506b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The EOES (Δεi=εE-Fci −εS-Fci) shows that the orbitals with significantly excess energies are Fe d-electron dominant.
Collapse
Affiliation(s)
- Shawkat Islam
- Molecular Model Discovery Laboratory
- Department of Chemistry and Biotechnology
- Faculty of Science, Engineering and Technology
- Swinburne University of Technology
- Melbourne
| | - Feng Wang
- Molecular Model Discovery Laboratory
- Department of Chemistry and Biotechnology
- Faculty of Science, Engineering and Technology
- Swinburne University of Technology
- Melbourne
| |
Collapse
|
20
|
Atkins AJ, Bauer M, Jacob CR. High-resolution X-ray absorption spectroscopy of iron carbonyl complexes. Phys Chem Chem Phys 2015; 17:13937-48. [DOI: 10.1039/c5cp01045d] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We apply high-energy-resolution fluorescence-detected (HERFD) X-ray absorption near-edge structure (XANES) spectroscopy to study iron carbonyl complexes.
Collapse
Affiliation(s)
- Andrew J. Atkins
- Karlsruhe Institute of Technology (KIT)
- Center for Functional Nanostructures and Institute of Physical Chemistry
- 76131 Karlsruhe
- Germany
| | - Matthias Bauer
- Universität Paderborn
- Naturwissenschaftliche Fakultät
- Department Chemie
- 33098 Paderborn
- Germany
| | - Christoph R. Jacob
- Karlsruhe Institute of Technology (KIT)
- Center for Functional Nanostructures and Institute of Physical Chemistry
- 76131 Karlsruhe
- Germany
- TU Braunschweig
| |
Collapse
|
21
|
Grupo Especializado de Qubmica Organometlica Awards 2014 / Hans G. A. Hellmann Prize for Christoph Jacob. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/anie.201411215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
22
|
|
23
|
Wenzel J, Wormit M, Dreuw A. Calculating core-level excitations and x-ray absorption spectra of medium-sized closed-shell molecules with the algebraic-diagrammatic construction scheme for the polarization propagator. J Comput Chem 2014; 35:1900-15. [DOI: 10.1002/jcc.23703] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 07/18/2014] [Accepted: 07/21/2014] [Indexed: 01/04/2023]
Affiliation(s)
- Jan Wenzel
- Interdisciplinary Center for Scientific Computing, Ruprecht-Karls University; Im Neuenheimer Feld 368 69120 Heidelberg Germany
| | - Michael Wormit
- Interdisciplinary Center for Scientific Computing, Ruprecht-Karls University; Im Neuenheimer Feld 368 69120 Heidelberg Germany
| | - Andreas Dreuw
- Interdisciplinary Center for Scientific Computing, Ruprecht-Karls University; Im Neuenheimer Feld 368 69120 Heidelberg Germany
| |
Collapse
|
24
|
Bauer M. HERFD-XAS and valence-to-core-XES: new tools to push the limits in research with hard X-rays? Phys Chem Chem Phys 2014; 16:13827-37. [PMID: 24905791 DOI: 10.1039/c4cp00904e] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this perspective, the HERFD-XANES (high energy resolution fluorescence detected X-ray absorption near edge structure) and Kβ2,5- or V2C-XES (valence-to-core X-ray emission spectroscopy) methods are discussed as new and powerful tools for chemical research with hard X-rays. This includes a brief survey of the underlying physical processes and the introduction of experimental issues. The potential of both methods to overcome limitations of conventional XAS (X-ray absorption spectroscopy) and to push the limits for obtaining new information about the electronic and geometric structures of metal centers, in the solid state structure or heterogeneous catalysts, but also in metal complexes and homogeneous catalysts, is discussed by presenting a survey of representative references and recent own studies, rounded off by a conclusion and outlook.
Collapse
Affiliation(s)
- Matthias Bauer
- Department Chemie, Universität Paderborn, Warburger Str. 100, 33098 Paderborn, Germany.
| |
Collapse
|
25
|
|
26
|
The role of Hartree–Fock exchange in the simulation of X-ray absorption spectra: A study of photoexcited. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.06.060] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
27
|
Chandrasekaran P, Chiang KP, Nordlund D, Bergmann U, Holland PL, DeBeer S. Sensitivity of X-ray core spectroscopy to changes in metal ligation: a systematic study of low-coordinate, high-spin ferrous complexes. Inorg Chem 2013; 52:6286-98. [PMID: 23662855 DOI: 10.1021/ic3021723] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In order to assess the sensitivity and complementarity of X-ray absorption and emission spectroscopies for determining changes in the metal ligation sphere, a systematic experimental and theoretical study of iron model complexes has been carried out. A series of high-spin ferrous complexes, in which the ligation sphere has been varied from a three-coordinate complex, [L(tBu)Fe(SPh)] (1) (where L(tBu) = bulky β-diketiminate ligand; SPh = phenyl thiolate) to four-coordinate complexes [L(tBu)Fe(SPh)(X)] (where X = CN(t)Bu (2); 1-methylimidazole (3); or N,N-dimethylformamide (DMF) (4)), has been investigated using a combination of Fe K-edge X-ray absorption (XAS) and Kβ X-ray emission (XES) spectroscopies. The Fe K XAS pre-edge and edge of all four complexes are consistent with a high-spin ferrous assignment, with the largest differences in the pre-edge intensities attributed to changes in covalency of the fourth coordination site. The X-ray emission spectra show pronounced changes in the valence to core region (V2C) as the identity of the coordinated ligand is varied. The experimental results have been correlated to density functional theory (DFT) calculations, to understand key molecular orbital contributions to the observed absorption and emission features. The calculations also have been extended to a series of hypothetical high-spin iron complexes to understand the sensitivity of XAS and XES techniques to different ligand protonation states ([L(tBu)Fe(II)(SPh)(NHn)](3-n) (n = 3, 2, 1, 0)), metal oxidation states [L(tBu)Fe(SPh)(N)](n-) (n = 3, 2, 1), and changes in the ligand identity [L(tBu)Fe(IV)(SPh)(X)](n-) (X = C(4-), N(3-), O(2-); n = 2, 1, 0). This study demonstrates that XAS pre-edge data have greater sensitivity to changes in oxidation state, while valence to core (V2C) XES data provide a more sensitive probe of ligand identity and protonation state. The combination of multiple X-ray spectroscopic methods with DFT results thus has the potential to provide for detailed characterization of complex inorganic systems in both chemical and biological catalysis.
Collapse
Affiliation(s)
- P Chandrasekaran
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | | | | | | | | | | |
Collapse
|
28
|
Bernadotte S, Atkins AJ, Jacob CR. Origin-independent calculation of quadrupole intensities in X-ray spectroscopy. J Chem Phys 2013. [PMID: 23205980 DOI: 10.1063/1.4766359] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
For electronic excitations in the ultraviolet and visible range of the electromagnetic spectrum, the intensities are usually calculated within the dipole approximation, which assumes that the oscillating electric field is constant over the length scale of the transition. For the short wavelengths used in hard X-ray spectroscopy, the dipole approximation may not be adequate. In particular, for metal K-edge X-ray absorption spectroscopy (XAS), it becomes necessary to include higher-order contributions. In quantum-chemical approaches to X-ray spectroscopy, these so-called quadrupole intensities have so far been calculated by including contributions depending on the square of the electric-quadrupole and magnetic-dipole transition moments. However, the resulting quadrupole intensities depend on the choice of the origin of the coordinate system. Here, we show that for obtaining an origin-independent theory, one has to include all contributions that are of the same order in the wave vector consistently. This leads to two additional contributions depending on products of the electric-dipole and electric-octupole and of the electric-dipole and magnetic-quadrupole transition moments, respectively. We have implemented such an origin-independent calculation of quadrupole intensities in XAS within time-dependent density-functional theory, and demonstrate its usefulness for the calculation of metal and ligand K-edge XAS spectra of transition metal complexes.
Collapse
Affiliation(s)
- Stephan Bernadotte
- Karlsruhe Institute of Technology (KIT), Center for Functional Nanostructures, Wolfgang-Gaede-Str. 1a, 76131 Karlsruhe, Germany
| | | | | |
Collapse
|
29
|
Atkins AJ, Bauer M, Jacob CR. The chemical sensitivity of X-ray spectroscopy: high energy resolution XANES versus X-ray emission spectroscopy of substituted ferrocenes. Phys Chem Chem Phys 2013; 15:8095-105. [PMID: 23579736 DOI: 10.1039/c3cp50999k] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
X-ray spectroscopy at the metal K-edge is an important tool for understanding catalytic processes and provides insight into the geometric and electronic structures of transition metal complexes. In particular, X-ray emission-based methods such as high-energy resolution fluorescence detection (HERFD), X-ray absorption near-edge spectroscopy (XANES) and valence-to-core X-ray emission spectroscopy (V2C-XES) hold the promise of providing increased chemical sensitivity compared to conventional X-ray absorption spectroscopy. Here, we explore the ability of HERFD-XANES and V2C-XES spectroscopy to distinguish substitutions beyond the directly coordinated atoms for the example of ferrocene and selected ferrocene derivatives. The experimental spectra are assigned and interpreted through the use of density functional theory (DFT) calculations. We find that while the pre-edge peaks in the HERFD-XANES spectra are affected by substituents at the cyclopentadienyl ring containing π-bonds [A. J. Atkins, Ch. R. Jacob and M. Bauer, Chem.-Eur. J., 2012, 18, 7021], the V2C-XES spectra are virtually unchanged. The pre-edge in HERFD-XANES probes the weak transition to unoccupied metal d-orbitals, while the V2C-XES spectra are determined by dipole-allowed transitions from occupied ligand orbitals to the 1s core hole. The latter turn out to be less sensitive to changes beyond the first coordination shell.
Collapse
Affiliation(s)
- Andrew J Atkins
- Karlsruhe Institute of Technology (KIT), Center for Functional Nanostructures and Institute of Physical Chemistry, Wolfgang-Gaede-Str. 1a, 76131 Karlsruhe, Germany
| | | | | |
Collapse
|
30
|
Yang Y, Yu L. Theoretical investigations of ferrocene/ferrocenium solvation in imidazolium-based room-temperature ionic liquids. Phys Chem Chem Phys 2013; 15:2669-83. [DOI: 10.1039/c2cp42876h] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|