1
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Kaul N, Asempa E, Valdez-Moreira JA, Smith JM, Jakubikova E, Hammarström L. Enter Mn IV-NHC: A Dark Photooxidant with a Long-Lived Charge-Transfer Excited State. J Am Chem Soc 2024; 146:24619-24629. [PMID: 39106331 PMCID: PMC11378296 DOI: 10.1021/jacs.4c08588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/09/2024]
Abstract
Detailed photophysical investigation of a Mn(IV)-carbene complex has revealed that excitation into its lowest-energy absorption band (∼500 nm) results in the formation of an energetic ligand-to-metal charge-transfer (LMCT) state with a lifetime of 15 ns. To the best of our knowledge, this is the longest lifetime reported for charge-transfer states of first-row-based transition metal complexes in solution, barring those based on Cu, with a d10 configuration. A so-called superoxidant, Mn(IV)-carbene exhibits an excited state potential typically only harnessed via excited states of reactive organic radical species. Furthermore, the long-lived excited state in this case is found to be a dark doublet, with its transition to the quartet ground state being spin-forbidden, a contrast to most first-row literature examples, and a possible cause of the long lifetime. Showcasing excited state properties which in some cases exceed those of complexes based on precious metals, these findings not only advance the library of earth-abundant photosensitizers but also shed general insight into the photophysics of d3 and related Mn complexes.
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Affiliation(s)
- Nidhi Kaul
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
| | - Eyram Asempa
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Juan A Valdez-Moreira
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Jeremy M Smith
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Elena Jakubikova
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Leif Hammarström
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
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2
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Bednarska-Szczepaniak K, Hałagan K, Szwed M, Przelazły E, Leśnikowski ZJ. Quantum Chemical and Biological Insights into Redox Activity of Metallacarborane Complexes in Cancer Cells. J Chem Inf Model 2024; 64:6521-6541. [PMID: 39140958 DOI: 10.1021/acs.jcim.4c00394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
A relationship between the electronic properties of metal ions in metallacarboranes and their ability to modulate mitochondrial oxidase activity and membrane hyperpolarization in cancer cells was demonstrated. Quantum chemistry methods, including DFT and molecular dynamics simulations, were used to understand the oxidized and reduced forms of metallacarboranes and their intramolecular rotatory behavior. According to the low-spin assumption for metal ions, the intramolecular oscillations of cluster ligands in metallacarboranes are significantly influenced by the type of metal and correspond to the cellular uptake of these complexes in vitro. In particular, the low-spin iron compound may be a new xenogeneic booster of redox homeostasis in cancer cells resistant to cisplatin, which induces metabolic 'exhaustion' of cancer cells and their death.
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Affiliation(s)
- Katarzyna Bednarska-Szczepaniak
- Laboratory of Medicinal Chemistry, Polish Academy of Sciences, Institute of Medical Biology, 106 Lodowa, 92-232 Lodz, Poland
| | - Krzysztof Hałagan
- Department of Molecular Physics, Faculty of Chemistry, Lodz University of Technology, Żeromskiego 116, 90-924 Lodz, Poland
| | - Marzena Szwed
- Department of Medical Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Institute of Biophysics, Pomorska 141/143, 90-236 Lodz, Poland
| | - Ewelina Przelazły
- Laboratory of Medicinal Chemistry, Polish Academy of Sciences, Institute of Medical Biology, 106 Lodowa, 92-232 Lodz, Poland
| | - Zbigniew J Leśnikowski
- Laboratory of Medicinal Chemistry, Polish Academy of Sciences, Institute of Medical Biology, 106 Lodowa, 92-232 Lodz, Poland
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3
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Krämer K, Schmitz M, Kelm H, van Wüllen C, Krüger HJ. Unexpected Reduction of a Coordinated Diazapyridinophane Ligand Bound to Chromium(III) Ion Leading to Delocalization of the Unpaired Electron across Two Isolated Pyridine Units. Chemistry 2024; 30:e202301099. [PMID: 37903737 DOI: 10.1002/chem.202301099] [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: 04/06/2023] [Revised: 10/06/2023] [Accepted: 10/27/2023] [Indexed: 11/01/2023]
Abstract
In the tetraazamacrocyclic ligand N,N'-dimethyl-2,11-diaza-[3.3](2,6)pyridinophane (L-N4 Me2 ), the two pyridine units are separated from each other by sp3 -hybridized triatomic bridges. Such electronically isolated pyridine moieties are considerably less prone to reductions than di- or triimines. A detailed structural, magnetic, and spectroscopic investigation of the complexes [Cr(L-N4 Me2 )(OAc)2 ] and [Cr(L-N4 Me2 )(OAc)2 ](PF6 ), in combination with theoretical calculations, reveals that the reduced complex must be described as a chromium(III) ion coordinated to the anionic radical ligand (L-N4 Me2 )⋅- rather than a low-spin chromium(II) ion bound to closed-shell ligands. Thus, it is, to the best of our knowledge, only the second example of a stable and structurally characterized metal complex containing a reduced isolated pyridine unit. The stability is attributed to the delocalization of the unpaired electron across the two pyridine units, mediated by their interaction to the metal ion.
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Affiliation(s)
- Kristin Krämer
- RPTU Kaiserslautern-Landau, Department of Chemistry, Erwin-Schrödinger Straße 54, 67663, Kaiserslautern, Germany
| | - Markus Schmitz
- RPTU Kaiserslautern-Landau, Department of Chemistry, Erwin-Schrödinger Straße 54, 67663, Kaiserslautern, Germany
| | - Harald Kelm
- RPTU Kaiserslautern-Landau, Department of Chemistry, Erwin-Schrödinger Straße 54, 67663, Kaiserslautern, Germany
| | - Christoph van Wüllen
- RPTU Kaiserslautern-Landau, Department of Chemistry and Forschungszentrum OPTIMAS, Erwin-Schrödinger Straße 54, 67663, Kaiserslautern, Germany
| | - Hans-Jörg Krüger
- RPTU Kaiserslautern-Landau, Department of Chemistry, Erwin-Schrödinger Straße 54, 67663, Kaiserslautern, Germany
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4
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Pitcairn J, Iliceto A, Cañadillas-Delgado L, Fabelo O, Liu C, Balz C, Weilhard A, Argent SP, Morris AJ, Cliffe MJ. Low-Dimensional Metal-Organic Magnets as a Route toward the S = 2 Haldane Phase. J Am Chem Soc 2023; 145:1783-1792. [PMID: 36626185 PMCID: PMC9881000 DOI: 10.1021/jacs.2c10916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Indexed: 01/11/2023]
Abstract
Metal-organic magnets (MOMs), modular magnetic materials where metal atoms are connected by organic linkers, are promising candidates for next-generation quantum technologies. MOMs readily form low-dimensional structures and so are ideal systems to realize physical examples of key quantum models, including the Haldane phase, where a topological excitation gap occurs in integer-spin antiferromagnetic (AFM) chains. Thus, far the Haldane phase has only been identified for S = 1, with S ≥ 2 still unrealized because the larger spin imposes more stringent requirements on the magnetic interactions. Here, we report the structure and magnetic properties of CrCl2(pym) (pym = pyrimidine), a new quasi-1D S = 2 AFM MOM. We show, using X-ray and neutron diffraction, bulk property measurements, density-functional theory calculations, and inelastic neutron spectroscopy (INS), that CrCl2(pym) consists of AFM CrCl2 spin chains (J1 = -1.13(4) meV) which are weakly ferromagnetically coupled through bridging pym (J2 = 0.10(2) meV), with easy-axis anisotropy (D = -0.15(3) meV). We find that, although small compared to J1, these additional interactions are sufficient to prevent observation of the Haldane phase in this material. Nevertheless, the proximity to the Haldane phase together with the modularity of MOMs suggests that layered Cr(II) MOMs are a promising family to search for the elusive S = 2 Haldane phase.
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Affiliation(s)
- Jem Pitcairn
- School
of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Andrea Iliceto
- School
of Metallurgy and Materials, University
of Birmingham, Elms Road,
Edgbaston, Birmingham B15
2TT, United Kingdom
| | | | - Oscar Fabelo
- Institut
Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble, France
| | - Cheng Liu
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Christian Balz
- ISIS
Neutron and Muon Source, STFC Rutherford
Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, United Kingdom
| | - Andreas Weilhard
- School
of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Stephen P. Argent
- School
of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Andrew J. Morris
- School
of Metallurgy and Materials, University
of Birmingham, Elms Road,
Edgbaston, Birmingham B15
2TT, United Kingdom
| | - Matthew J. Cliffe
- School
of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
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5
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Momeni BZ, Karimi S, Janczak J. Penta-coordinated Cr(II) and Cu(II) complexes appended with 4′-(4-quinolyl)-2,2′:6′,2″-terpyridine: crystal structure, Hirshfeld Surface analysis, luminescence and thermal properties. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.134245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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6
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Cook BJ, Barona M, Johnson SI, Raugei S, Bullock RM. Weakening the N-H Bonds of NH 3 Ligands: Triple Hydrogen-Atom Abstraction to Form a Chromium(V) Nitride. Inorg Chem 2022; 61:11165-11172. [PMID: 35829761 DOI: 10.1021/acs.inorgchem.2c01115] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Weakening and cleaving N-H bonds is crucial for improving molecular ammonia (NH3) oxidation catalysts. We report the synthesis and H-atom-abstraction reaction of bis(ammonia)chromium porphyrin complexes Cr(TPP)(NH3)2 and Cr(TMP)(NH3)2 (TPP = 5,10,15,20-tetraphenyl-meso-porphyrin and TMP = 5,10,15,20-tetramesityl-meso-porphyrin) using bulky aryloxyl radicals. The triple H-atom-abstraction reaction results in the formation of CrV(por)(≡N), with the nitride derived from NH3, as indicated by UV-vis and IR and single-crystal structural determination of Cr(TPP)(≡N). Subsequent oxidation of this chromium(V) nitrido complex results in the formation of CrIII(por), with scission of the Cr≡N bond. Computational analysis illustrates the progression from CrII to CrV and evaluates the energetics of abstracting H atoms from CrII-NH3 to generate CrV≡N. The formation and isolation of CrV(por)(≡N) illustrates the stability of these species and the need to chemically activate the nitride ligand for atom transfer or N-N coupling reactivity.
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Affiliation(s)
- Brian J Cook
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Melissa Barona
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Samantha I Johnson
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Simone Raugei
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - R Morris Bullock
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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7
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Joyce JP, Portillo RI, Rappé AK, Shores MP. Doublet Ground State in a Vanadium(II) Complex: Redox and Coordinative Noninnocence of Tripodal Ligand Architecture. Inorg Chem 2022; 61:6376-6391. [DOI: 10.1021/acs.inorgchem.1c03418] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Justin P. Joyce
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Romeo I. Portillo
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Anthony K. Rappé
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Matthew P. Shores
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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8
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Abstract
In molecular photochemistry, charge-transfer emission is well understood and widely exploited. In contrast, luminescent metal-centered transitions only came into focus in recent years. This gave rise to strongly phosphorescent CrIII complexes with a d3 electronic configuration featuring luminescent metal-centered excited states which are characterized by the flip of a single spin. These so-called spin-flip emitters possess unique properties and require different design strategies than traditional charge-transfer phosphors. In this review, we give a brief introduction to ligand field theory as a framework to understand this phenomenon and outline prerequisites for efficient spin-flip emission including ligand field strength, symmetry, intersystem crossing and common deactivation pathways using CrIII complexes as instructive examples. The recent progress and associated challenges of tuning the energies of emissive excited states and of emerging applications of the unique photophysical properties of spin-flip emitters are discussed. Finally, we summarize the current state-of-the-art and challenges of spin-flip emitters beyond CrIII with d2, d3, d4 and d8 electronic configuration, where we mainly cover pseudooctahedral molecular complexes of V, Mo, W, Mn, Re and Ni, and highlight possible future research opportunities.
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9
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Mukherjee D, Manna RN, Saha P, Mandal U, Mitra M. Electronic and molecular characterization of an air-stable Cr(II) complex containing azo-anion-radicals. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2020.129247] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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10
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Dill RD, Portillo RI, Shepard SG, Shores MP, Rappé AK, Damrauer NH. Long-Lived Mixed 2MLCT/MC States in Antiferromagnetically Coupled d 3 Vanadium(II) Bipyridine and Phenanthroline Complexes. Inorg Chem 2020; 59:14706-14715. [PMID: 32886504 DOI: 10.1021/acs.inorgchem.0c01950] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Exploration of [V(bpy)3]2+ and [V(phen)3]2+ (bpy = 2,2'-bipyridine; phen = 1,10-phenanthroline) using electronic spectroscopy reveals an ultrafast excited-state decay process and implicates a pair of low-lying doublets with mixed metal-to-ligand charge-transfer (MLCT) and metal-centered (MC) character. Transient absorption (TA) studies of the vanadium(II) species probing in the visible and near-IR, in combination with spectroelectrochemical techniques and computational chemistry, lead to the conclusion that after excitation into the intense and broad visible 4MLCT ← 4GS (ground-state) absorption band (ε400-700 nm = 900-8000 M-1 cm-1), the 4MLCT state rapidly (τisc < 200 fs) relaxes to the upper of two doublet states with mixed MLCT/MC character. Electronic interconversion (τ ∼ 2.5-3 ps) to the long-lived excited state follows, which we attribute to formation of the lower mixed state. Following these initial dynamics, GS recovery ensues with τ = 430 ps and 1.6 ns for [V(bpy)3]2+ and [V(phen)3]2+, respectively. This stands in stark contrast with isoelectronic [Cr(bpy)3]3+, which rapidly forms a long-lived doublet metal-centered (2MC) state following photoexcitation and lacks strong visible GS absorption character. 2MLCT character in the long-lived states of the vanadium(II) species produces geometric distortion and energetic stabilization, both of which accelerate nonradiative decay to the GS compared to [Cr(bpy)3]3+, where the GS and 2MC are well nested. These conclusions are significant because (i) long-lived states with MLCT character are rare in first-row transition-metal complexes and (ii) the presence of a 2MLCT state at lower energy than the 4MLCT state has not been previously considered. The spin assignment of charge-transfer states in open-shell transition-metal complexes is not trivial; when metal-ligand interaction is strong, low-spin states must be carefully considered when assessing reactivity and decay from electronic excited states.
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Affiliation(s)
- Ryan D Dill
- Department of Chemistry and Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, United States
| | - Romeo I Portillo
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Samuel G Shepard
- Department of Chemistry and Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, United States
| | - Matthew P Shores
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Anthony K Rappé
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Niels H Damrauer
- Department of Chemistry and Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, United States
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11
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Vinum MG, Voigt L, Hansen SH, Bell C, Clark KM, Larsen RW, Pedersen KS. Ligand field-actuated redox-activity of acetylacetonate. Chem Sci 2020; 11:8267-8272. [PMID: 34094180 PMCID: PMC8163028 DOI: 10.1039/d0sc01836h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 07/15/2020] [Indexed: 11/24/2022] Open
Abstract
The quest for simple ligands that enable multi-electron metal-ligand redox chemistry is driven by a desire to replace noble metals in catalysis and to discover novel chemical reactivity. The vast majority of simple ligand systems display electrochemical potentials impractical for catalytic cycles, illustrating the importance of creating new strategies towards energetically aligned ligand frontier and transition metal d orbitals. We herein demonstrate the ability to chemically control the redox-activity of the ubiquitous acetylacetonate (acac) ligand. By employing the ligand field of high-spin Cr(ii) as a switch, we were able to chemically tailor the occurrence of metal-ligand redox events via simple coordination or decoordination of the labile auxiliary ligands. The mechanism of ligand field actuation can be viewed as a destabilization of the d z 2 orbital relative to the π* LUMO of acac, which proffers a generalizable strategy to synthetically engineer redox-activity with seemingly redox-inactive ligands.
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Affiliation(s)
- Morten Gotthold Vinum
- Department of Chemistry, Technical University of Denmark Kemitorvet Kgs. Lyngby DK-2800 Denmark
| | - Laura Voigt
- Department of Chemistry, Technical University of Denmark Kemitorvet Kgs. Lyngby DK-2800 Denmark
| | - Steen H Hansen
- Department of Chemistry, Technical University of Denmark Kemitorvet Kgs. Lyngby DK-2800 Denmark
| | - Colby Bell
- Department of Chemistry, The University of Memphis Memphis TN USA
| | | | - René Wugt Larsen
- Department of Chemistry, Technical University of Denmark Kemitorvet Kgs. Lyngby DK-2800 Denmark
| | - Kasper S Pedersen
- Department of Chemistry, Technical University of Denmark Kemitorvet Kgs. Lyngby DK-2800 Denmark
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12
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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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13
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Chan SC, Ang ZZ, Gupta P, Ganguly R, Li Y, Ye S, England J. Carbodicarbene Ligand Redox Noninnocence in Highly Oxidized Chromium and Cobalt Complexes. Inorg Chem 2020; 59:4118-4128. [PMID: 32101411 DOI: 10.1021/acs.inorgchem.0c00153] [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
Carbodicarbenes (CDCs) possess two lone pairs of electrons on their central carbone C atom (Ccarbone). Coordination to a transition metal via a σ bond leaves one pair of electrons with appropriate symmetry for π donation to the metal. However, the high energy of the latter also renders the CDC ligand potentially redox-active. Herein, we explore these alternatives in the redox series [Cr(L)2]n+ and [Co(L)2]n+ (n = 2-5), where L is a tridentate ligand comprised of a central CDC and two flanking pyridine donors. To this end, all members of both redox series were synthesized and their electronic structures were investigated by using a combination of 1H NMR, Evans' NMR, IR, UV-vis, and EPR spectroscopies, SQUID magnetometry, X-ray crystallography, and density functional theory studies. Whereas [CoII(L)2]2+ is a straightforward low-spin (S = 1/2) cobalt(II) complex, the corresponding chromium complex was found to feature an electronic structure that is intermediate between the two limiting resonance forms [CrIII(L•-)(L)]2+ and [CrII(L)2]2+. In the case of the tri-, tetra-, and pentacationic complexes, the qualitatively identical electronic structures [MIII(L)2]3+, [MIII(L•+)(L)]4+, and [MIII(L•+)2]5+ were observed for both metals. Thus, the metal ions retain a 3+ oxidation state throughout, and the higher redox states contain oxidized ligands. The majority of the unpaired spin on the cation radical ligands was calculated to be localized in π-symmetry orbitals on the coordinated Ccarbone atoms. Analogous behavior was previously reported for the corresponding iron redox series and, as such, redox noninnocence in oxidized CDC and, more broadly, carbone complexes is likely widely accessible.
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Affiliation(s)
- Siu-Chung Chan
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), 21 Nanyang Link, 637371, Singapore
| | - Zhi Zhong Ang
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), 21 Nanyang Link, 637371, Singapore
| | - Puneet Gupta
- Max-Plank-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr D-45470, Germany
| | - Rakesh Ganguly
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), 21 Nanyang Link, 637371, Singapore
| | - Yongxin Li
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), 21 Nanyang Link, 637371, Singapore
| | - Shengfa Ye
- Max-Plank-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr D-45470, Germany.,State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Jason England
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), 21 Nanyang Link, 637371, Singapore
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14
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Vinum MG, Voigt L, Bell C, Mihrin D, Larsen RW, Clark KM, Pedersen KS. Evidence for Non-Innocence of a β-Diketonate Ligand. Chemistry 2020; 26:2143-2147. [PMID: 31721307 DOI: 10.1002/chem.201904899] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Indexed: 11/07/2022]
Abstract
β-Diketonates, such as acetylacetonate, are amongst the most common bidentate ligands towards elements across the entire periodic table and are considered wholly redox-inactive in their complexes. Herein we show that complexation of 1,1,1,5,5,5-hexafluoroacetylacetonate (hfac- ) to CrII spontaneously affords CrIII and a reduced β-diketonate radical ligand scaffold, as evidenced by crystallographic analysis, magnetic measurements, optical spectroscopy, reactivity studies, and DFT calculations. The possibility of harnessing β-diketonates as electron reservoirs opens up possibilities for new metal-ligand concerted reactivity in the ubiquitous β-diketonate coordination chemistry.
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Affiliation(s)
- Morten Gotthold Vinum
- Department of Chemistry, Technical University of Denmark, Kemitorvet, Building 207, 2800, Kgs. Lyngby, Denmark
| | - Laura Voigt
- Department of Chemistry, Technical University of Denmark, Kemitorvet, Building 207, 2800, Kgs. Lyngby, Denmark
| | - Colby Bell
- Department of Chemistry, The University of Memphis, Memphis, TN, USA
| | - Dmytro Mihrin
- Department of Chemistry, Technical University of Denmark, Kemitorvet, Building 207, 2800, Kgs. Lyngby, Denmark
| | - René Wugt Larsen
- Department of Chemistry, Technical University of Denmark, Kemitorvet, Building 207, 2800, Kgs. Lyngby, Denmark
| | | | - Kasper S Pedersen
- Department of Chemistry, Technical University of Denmark, Kemitorvet, Building 207, 2800, Kgs. Lyngby, Denmark
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15
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Katari M, Carmichael D, Jacquemin D, Frison G. Structure of Electronically Reduced N-Donor Bidentate Ligands and Their Heteroleptic Four-Coordinate Zinc Complexes: A Survey of Density Functional Theory Results. Inorg Chem 2019; 58:7169-7179. [PMID: 31117621 DOI: 10.1021/acs.inorgchem.8b03549] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of Hartree-Fock exchange in describing the structural changes occurring upon reduction of bipyridine-based ligands and their complexes is investigated within the framework of density functional theory (DFT) calculations. A set of four free ligands in their neutral and radical anionic forms, and two of their zinc complexes in their dicationic and monocationic radical forms, is used to compare a large panel of pure, conventional, and long-range corrected hybrid DFT functionals; coupled cluster single and double calculations are used alongside experimental results as benchmarks. Particular attention has been devoted to the magnitude of the change, upon reduction, of the Δ-parameter, which measures the difference between the Cpy-Cpy and the C-N bond lengths in bipyridine ligand and is known to experimentally correlate with the charge of the ligands. Our results indicate that the structural changes significantly depend on the amount of exact exchange included in the functional. A progressive evolution is observed for the free ligands, whereas two distinct sets of results are obtained for the complexes. Functionals with a small degree of HF exchange, e.g., B3LYP, do not adequately describe geometric changes for the considered species, and, quite surprisingly, the same holds for the CC2 method. The best agreement to experimental and CCSD values is obtained with functionals that include a significant but not excessive part of exact exchange, e.g., CAM-B3LYP, M06-2X, and ωB97X-D. The calculated localization of the added electron after reduction, which depends on the self-interaction error, is used to rationalize these outcomes. Static correlation is also shown to play a role in the accurate description of the electronic structure.
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Affiliation(s)
| | - Duncan Carmichael
- LCM, CNRS, Ecole Polytechnique , IP Paris , F-91128 Palaiseau , France
| | - Denis Jacquemin
- University of Nantes , CNRS, CEISAM (UMR 6230), 2 chemin de la Houssinière , 44322 Nantes , Cedex 03 , France
| | - Gilles Frison
- LCM, CNRS, Ecole Polytechnique , IP Paris , F-91128 Palaiseau , France
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16
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Laskar P, Yamamoto K, Nishi K, Ikeda H, Tsurugi H, Mashima K. Cβ–Cβ Bond Fission of Metallacyclopentadiene over a Low-Valent Ditantalum Scaffold. Organometallics 2019. [DOI: 10.1021/acs.organomet.8b00914] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Payel Laskar
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Keishi Yamamoto
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Kohei Nishi
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Hideaki Ikeda
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Hayato Tsurugi
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Kazushi Mashima
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
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17
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Leone G, Groppo E, Zanchin G, Martino GA, Piovano A, Bertini F, Martí-Rujas J, Parisini E, Ricci G. Concerted Electron Transfer in Iminopyridine Chromium Complexes: Ligand Effects on the Polymerization of Various (Di)olefins. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00812] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Giuseppe Leone
- CNR-Istituto per lo Studio delle Macromolecole (ISMAC), via A. Corti 12, I-20133 Milano, Italy
| | - Elena Groppo
- Dipartimento di Chimica, NIS Interdepartmental Research Center and INSTM Reference Center, Università degli Studi di Torino, Via G. Quarello 15A, I-10135 Torino, Italy
| | - Giorgia Zanchin
- CNR-Istituto per lo Studio delle Macromolecole (ISMAC), via A. Corti 12, I-20133 Milano, Italy
| | - Giorgia A. Martino
- Dipartimento di Chimica, NIS Interdepartmental Research Center and INSTM Reference Center, Università degli Studi di Torino, Via G. Quarello 15A, I-10135 Torino, Italy
| | - Alessandro Piovano
- Dipartimento di Chimica, NIS Interdepartmental Research Center and INSTM Reference Center, Università degli Studi di Torino, Via G. Quarello 15A, I-10135 Torino, Italy
| | - Fabio Bertini
- CNR-Istituto per lo Studio delle Macromolecole (ISMAC), via A. Corti 12, I-20133 Milano, Italy
| | - Javier Martí-Rujas
- Center for Nano Science and Technology at Polimi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, I-20133 Milano, Italy
| | - Emilio Parisini
- Center for Nano Science and Technology at Polimi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, I-20133 Milano, Italy
| | - Giovanni Ricci
- CNR-Istituto per lo Studio delle Macromolecole (ISMAC), via A. Corti 12, I-20133 Milano, Italy
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18
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Doistau B, Collet G, Bolomey EA, Sadat-Noorbakhsh V, Besnard C, Piguet C. Heteroleptic Ter–Bidentate Cr(III) Complexes as Tunable Optical Sensitizers. Inorg Chem 2018; 57:14362-14373. [PMID: 30376321 DOI: 10.1021/acs.inorgchem.8b02530] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Benjamin Doistau
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Guillaume Collet
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Emilio Acuña Bolomey
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Vida Sadat-Noorbakhsh
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Céline Besnard
- Laboratory of Crystallography, University of Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Claude Piguet
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
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19
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Glootz K, Kratzert D, Himmel D, Kastro A, Yassine Z, Findeisen T, Krossing I. Tetracationic Gallium Cluster Cations. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201807486] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Kim Glootz
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Germany
| | - Daniel Kratzert
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Germany
| | - Daniel Himmel
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Germany
| | - Aho Kastro
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Germany
| | - Zeinab Yassine
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Germany
| | - Tobias Findeisen
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Germany
| | - Ingo Krossing
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Germany
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20
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Glootz K, Kratzert D, Himmel D, Kastro A, Yassine Z, Findeisen T, Krossing I. Tetracationic Gallium Cluster Cations. Angew Chem Int Ed Engl 2018; 57:14203-14206. [DOI: 10.1002/anie.201807486] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/16/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Kim Glootz
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Germany
| | - Daniel Kratzert
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Germany
| | - Daniel Himmel
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Germany
| | - Aho Kastro
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Germany
| | - Zeinab Yassine
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Germany
| | - Tobias Findeisen
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Germany
| | - Ingo Krossing
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstraße 21 79104 Freiburg Germany
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21
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Perlepe P, Oyarzabal I, Pedersen KS, Negrier P, Mondieig D, Rouzières M, Hillard EA, Wilhelm F, Rogalev A, Suturina EA, Mathonière C, Clérac R. Cr(pyrazine)2(OSO2CH3)2: A two-dimensional coordination polymer with an antiferromagnetic ground state. Polyhedron 2018. [DOI: 10.1016/j.poly.2018.07.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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22
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Pedersen KS, Perlepe P, Aubrey ML, Woodruff DN, Reyes-Lillo SE, Reinholdt A, Voigt L, Li Z, Borup K, Rouzières M, Samohvalov D, Wilhelm F, Rogalev A, Neaton JB, Long JR, Clérac R. Formation of the layered conductive magnet CrCl 2(pyrazine) 2 through redox-active coordination chemistry. Nat Chem 2018; 10:1056-1061. [PMID: 30202103 DOI: 10.1038/s41557-018-0107-7] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 06/05/2018] [Indexed: 11/09/2022]
Abstract
The unique properties of graphene, transition-metal dichalcogenides and other two-dimensional (2D) materials have boosted interest in layered coordination solids. In particular, 2D materials that behave as both conductors and magnets could find applications in quantum magnetoelectronics and spintronics. Here, we report the synthesis of CrCl2(pyrazine)2, an air-stable layered solid, by reaction of CrCl2 with pyrazine (pyz). This compound displays a ferrimagnetic order below ∼55 K, reflecting the presence of strong magnetic interactions. Electrical conductivity measurements demonstrate that CrCl2(pyz)2 reaches a conductivity of 32 mS cm-1 at room temperature, which operates through a 2D hopping-based transport mechanism. These properties are induced by the redox-activity of the pyrazine ligand, which leads to a smearing of the Cr 3d and pyrazine π states. We suggest that the combination of redox-active ligands and reducing paramagnetic metal ions represents a general approach towards tuneable 2D materials that consist of charge-neutral layers and exhibit both long-range magnetic order and high electronic conductivity.
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Affiliation(s)
- Kasper S Pedersen
- CNRS, CRPP, UMR 5031, Pessac, France. .,Univ. Bordeaux, CRPP, UMR 5031, Pessac, France. .,Department of Chemistry, Technical University of Denmark, Lyngby, Denmark.
| | - Panagiota Perlepe
- CNRS, CRPP, UMR 5031, Pessac, France.,Univ. Bordeaux, CRPP, UMR 5031, Pessac, France.,CNRS, ICMCB, UMR 5026, Pessac, France.,Univ. Bordeaux, ICMCB, UMR 5026, Pessac, France
| | - Michael L Aubrey
- Department of Chemistry, University of California Berkeley, Berkeley, CA, USA
| | | | - Sebastian E Reyes-Lillo
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Department of Physics, University of California Berkeley, Berkeley, CA, USA.,Departamento de Ciencias Físicas, Universidad Andres Bello, Santiago, Chile
| | - Anders Reinholdt
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Laura Voigt
- Department of Chemistry, Technical University of Denmark, Lyngby, Denmark
| | - Zheshen Li
- Department of Physics and Astronomy - Centre for Storage Ring Facilities (ISA), Aarhus University, Aarhus, Denmark
| | - Kasper Borup
- Center for Materials Crystallography, Department of Chemistry and iNano, Aarhus, Denmark
| | - Mathieu Rouzières
- CNRS, CRPP, UMR 5031, Pessac, France.,Univ. Bordeaux, CRPP, UMR 5031, Pessac, France
| | - Dumitru Samohvalov
- CNRS, CRPP, UMR 5031, Pessac, France.,Univ. Bordeaux, CRPP, UMR 5031, Pessac, France.,Sara Pharm Solutions, Bucharest, Romania
| | | | | | - Jeffrey B Neaton
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Department of Physics, University of California Berkeley, Berkeley, CA, USA.,Kavli Energy Nanosciences Institute at Berkeley, Berkeley, CA, USA
| | - Jeffrey R Long
- Department of Chemistry, University of California Berkeley, Berkeley, CA, USA.,Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, CA, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Rodolphe Clérac
- CNRS, CRPP, UMR 5031, Pessac, France. .,Univ. Bordeaux, CRPP, UMR 5031, Pessac, France.
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23
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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.
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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
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24
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Three oxidation states of the bis(3,5-di-tert-butyl-2-phenolato)azanido pincer ligand on chromium(III). Polyhedron 2018. [DOI: 10.1016/j.poly.2017.08.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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25
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Olafsen BE, Crescenzo GV, Moisey LP, Patrick BO, Smith KM. Photolytic Reactivity of Organometallic Chromium Bipyridine Complexes. Inorg Chem 2018; 57:9611-9621. [PMID: 29461816 DOI: 10.1021/acs.inorgchem.7b03195] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Known stable [Cr(bpy)2(Ph)2](BPh4) complexes undergo reductive elimination of biphenyl with visible-light photolysis using household incandescent or compact fluorescent light bulbs. A series of [Cr(R-bpy)2(Ar)2](X) complexes (R = H or CMe3; Ar = Ph, C6H4-CMe3, or C6H4-OMe; X = I, BPh4, or PF6) were prepared, and the effect of varying the bipyridine and aryl ligands on the UV-visible spectra and electrochemistry of the chromium(III) complexes was investigated. Photolysis of a mixture of two different bis(aryl) complexes gave only the homocoupled biaryl products by 1H NMR and gas chromatography/mass spectrometry analysis. The initial product of photoinduced reductive elimination of [Cr(bpy)2(Ar)2](PF6) was trapped with bipyridine to generate [Cr(bpy)3](PF6) and with benzoyl peroxide to form [Cr(bpy)2(O2CPh)2](PF6). The latter chromium(III) bis(benzoate) complex was also synthesized by the addition of bipyridine and PhCO2H to Cp2Cr, followed by air oxidation. The neutral Cr(bpy)(S2CNMe2)Ph2 complex also generated biphenyl upon visible-light photolysis. While the treatment of Cr(tBu-bpy)(dpm)Cl2 [dpm = (OCtBu)2CH] with AgO2CPh gave trans-Cr(tBu-bpy)(dpm)(O2CPh)2, reaction of the dichloro precursor with PhMgCl produced anionic [Cr(tBu-bpy)Ph3]- with [Mg(dpm)(THF)4]+ as the countercation, with both complexes characterized by single-crystal X-ray diffraction. Protonolysis of Cr(bpy)Ph3(THF) with 8-hydroxyquinoline produced Cr(bpy)(quin)Ph2, which generated biphenyl under visible-light photolysis, and the initial product of reductive elimination was trapped by bipyridine or benzoyl peroxide. A related Cr(bpy)(quin)2 complex was synthesized by protonolysis of Cr(bpy)[N(SiMe3)2]2 and characterized by single-crystal X-ray diffraction.
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Affiliation(s)
- Benjamin E Olafsen
- Department of Chemistry , University of British Columbia, Okanagan , 3247 University Way , Kelowna , British Columbia V1V 1V7 , Canada
| | - Giuseppe V Crescenzo
- Department of Chemistry , University of British Columbia, Okanagan , 3247 University Way , Kelowna , British Columbia V1V 1V7 , Canada
| | - Luke P Moisey
- Department of Chemistry , University of British Columbia, Okanagan , 3247 University Way , Kelowna , British Columbia V1V 1V7 , Canada
| | - Brian O Patrick
- Department of Chemistry , University of British Columbia, Vancouver , Vancouver , British Columbia V6T 1Z21 , Canada
| | - Kevin M Smith
- Department of Chemistry , University of British Columbia, Okanagan , 3247 University Way , Kelowna , British Columbia V1V 1V7 , Canada
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26
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Wilkin OM, Harris N, Rooms JF, Dixon EL, Bridgeman AJ, Young NA. How Inert, Perturbing, or Interacting Are Cryogenic Matrices? A Combined Spectroscopic (Infrared, Electronic, and X-ray Absorption) and DFT Investigation of Matrix-Isolated Iron, Cobalt, Nickel, and Zinc Dibromides. J Phys Chem A 2018; 122:1994-2029. [DOI: 10.1021/acs.jpca.7b09734] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Owen M. Wilkin
- Department
of Chemistry, The University of Hull, Kingston upon Hull HU6
7RX, U.K
| | - Neil Harris
- Department
of Chemistry, The University of Hull, Kingston upon Hull HU6
7RX, U.K
| | - John F. Rooms
- Department
of Chemistry, The University of Hull, Kingston upon Hull HU6
7RX, U.K
| | - Emma L. Dixon
- Department
of Chemistry, The University of Hull, Kingston upon Hull HU6
7RX, U.K
| | - Adam J. Bridgeman
- School
of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| | - Nigel A. Young
- Department
of Chemistry, The University of Hull, Kingston upon Hull HU6
7RX, U.K
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27
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Kurahashi T. Drastic Redox Shift and Electronic Structural Changes of a Manganese(III)-Salen Oxidation Catalyst upon Reaction with Hydroxide and Cyanide Ion. Inorg Chem 2018; 57:1066-1078. [DOI: 10.1021/acs.inorgchem.7b02474] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Takuya Kurahashi
- Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi 444-8787, Japan
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28
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MacMillan SN, Lancaster KM. X-ray Spectroscopic Interrogation of Transition-Metal-Mediated Homogeneous Catalysis: Primer and Case Studies. ACS Catal 2017. [DOI: 10.1021/acscatal.6b02875] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Samantha N. MacMillan
- Department of Chemistry and
Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Kyle M. Lancaster
- Department of Chemistry and
Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
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29
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Wolczanski PT. Flipping the Oxidation State Formalism: Charge Distribution in Organometallic Complexes As Reported by Carbon Monoxide. Organometallics 2017. [DOI: 10.1021/acs.organomet.6b00820] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Peter T. Wolczanski
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
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30
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Goforth SK, Gill TW, Weisbruch AE, Kane-Maguire KA, Helsel ME, Sun KW, Rodgers HD, Stanley FE, Goudy SR, Wheeler SK, Wheeler JF, Kane-Maguire NAP. Synthesis of cis-[Cr(diimine)2(1-methylimidazole)2](3+) Complexes and an Investigation of Their Interaction with Mononucleotides and Polynucleotides. Inorg Chem 2016; 55:1516-26. [PMID: 26836266 DOI: 10.1021/acs.inorgchem.5b02323] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
A protocol is presented for the synthesis of chromium(III) complexes of the type cis-[Cr(diimine)2(1-methylimidazole)2](3+). These compounds exhibit large excited-state oxidizing powers and strong luminescence in solution. Emission is quenched by added guanine, yielding rate constants that track the driving force for guanine oxidation. The cis-[Cr(TMP)(DPPZ)(1-MeImid)2](3+) species binds strongly to duplex DNA with a preference for AT base sites in the minor groove and may serve as a precursor for photoactivated DNA covalent adduct formation.
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Affiliation(s)
- Sarah K Goforth
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - Thomas W Gill
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - April E Weisbruch
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | | | - Marian E Helsel
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - Katherine W Sun
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - Hillary D Rodgers
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - Floyd E Stanley
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - Samuel R Goudy
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - Sandra K Wheeler
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - John F Wheeler
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - Noel A P Kane-Maguire
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
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31
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Yousif M, Cabelof AC, Martin PD, Lord RL, Groysman S. Synthesis of a mononuclear, non-square-planar chromium(ii) bis(alkoxide) complex and its reactivity toward organic carbonyls and CO2. Dalton Trans 2016; 45:9794-804. [DOI: 10.1039/c6dt00279j] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A rare non-square-planar mononuclear Cr(ii) bis(alkoxide) complex Cr(OR′)2(THF)2 is reported and its reactivity with organic carbonyls and CO2 is investigated.
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Affiliation(s)
- Maryam Yousif
- Department of Chemistry
- Wayne State University
- Detroit
- USA
| | - Alyssa C. Cabelof
- Department of Chemistry
- Wayne State University
- Detroit
- USA
- Department of Chemistry
| | | | - Richard L. Lord
- Department of Chemistry
- Grand Valley State University
- Allendale
- USA
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Zarkesh RA, Ichimura AS, Monson TC, Tomson NC, Anstey MR. Voltage clustering in redox-active ligand complexes: mitigating electronic communication through choice of metal ion. Dalton Trans 2016; 45:9962-9. [DOI: 10.1039/c6dt00422a] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Homoleptic bis(imino)acenaphthene complexes of aluminum, chromium, and gallium were synthesized, characterized and modeled to compare the orbital contributions of main group elements and transition metals in ligand-based redox events toward increasing energy density of battery electrolytes.
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Affiliation(s)
| | - Andrew S. Ichimura
- Department of Chemistry & Biochemistry
- San Francisco State University
- San Francisco
- USA
| | | | - Neil C. Tomson
- Department of Chemistry
- University of Pennsylvania
- Philadelphia
- USA
| | - Mitchell R. Anstey
- Sandia National Laboratories
- Livermore
- USA
- Department of Chemistry
- Davidson College
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DeGayner JA, Jeon IR, Harris TD. A series of tetraazalene radical-bridged M 2 (M = Cr III, Mn II, Fe II, Co II) complexes with strong magnetic exchange coupling. Chem Sci 2015; 6:6639-6648. [PMID: 29435213 PMCID: PMC5802272 DOI: 10.1039/c5sc02725j] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Accepted: 08/17/2015] [Indexed: 11/21/2022] Open
Abstract
The ability of tetraazalene radical bridging ligands to mediate exceptionally strong magnetic exchange coupling across a range of transition metal complexes is demonstrated. The redox-active bridging ligand N,N',N'',N'''-tetra(2-methylphenyl)-2,5-diamino-1,4-diiminobenzoquinone (NMePhLH2) was metalated to give the series of dinuclear complexes [(TPyA)2M2(NMePhL2-)]2+ (TPyA = tris(2-pyridylmethyl)amine, M = MnII, FeII, CoII). Variable-temperature dc magnetic susceptibility data for these complexes reveal the presence of weak superexchange interactions between metal centers, and fits to the data provide coupling constants of J = -1.64(1) and -2.16(2) cm-1 for M = MnII and FeII, respectively. One-electron reduction of the complexes affords the reduced analogues [(TPyA)2M2(NMePhL3-˙)]+. Following a slightly different synthetic procedure, the related complex [(TPyA)2CrIII2(NMePhL3-˙)]3+ was obtained. X-ray diffraction, cyclic voltammetry, and Mössbauer spectroscopy indicate the presence of radical NMePhL3-˙ bridging ligands in these complexes. Variable-temperature dc magnetic susceptibility data of the radical-bridged species reveal the presence of strong magnetic interactions between metal centers and ligand radicals, with simulations to data providing exchange constants of J = -626(7), -157(7), -307(9), and -396(16) cm-1 for M = CrIII, MnII, FeII, and CoII, respectively. Moreover, the strength of magnetic exchange in the radical-bridged complexes increases linearly with decreasing M-L bond distance in the oxidized analogues. Finally, ac magnetic susceptibility measurements reveal that [(TPyA)2Fe2(NMePhL3-˙)]+ behaves as a single-molecule magnet with a relaxation barrier of Ueff = 52(1) cm-1. These results highlight the ability of redox-active tetraazalene bridging ligands to enable dramatic enhancement of magnetic exchange coupling upon redox chemistry and provide a rare opportunity to examine metal-radical coupling trends across a transmetallic series of complexes.
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Affiliation(s)
- Jordan A DeGayner
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL , USA 60208-3113 .
| | - Ie-Rang Jeon
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL , USA 60208-3113 .
| | - T David Harris
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL , USA 60208-3113 .
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Roth CE, Dibenedetto A, Aresta M. Synthesis and Characterization of Chloro- and Alkyliron Complexes with N-Donor Ligands and Their Reactivity towards CO2. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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35
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Moon D, Choi JH. Crystal structure of cis-aqua-chlorido-bis-(1,10-phenanthroline-κ(2) N,N')chromium(III) tetra-chlorido-zincate monohydrate from synchrotron data. Acta Crystallogr E Crystallogr Commun 2015; 71:288-90. [PMID: 25844190 PMCID: PMC4350701 DOI: 10.1107/s2056989015003266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 02/16/2015] [Indexed: 11/11/2022]
Abstract
The structure of the title compound, [CrCl(C12H8N2)2(H2O)][ZnCl4]·H2O, has been determined from synchrotron data. The Cr(III) ion is bonded to four N atoms from two 1,10-phenanthroline (phen) ligands, one water mol-ecule and a Cl atom in a cis arrangement, displaying an overall distorted octa-hedral coordination environment. The Cr-N(phen) bond lengths are in the range of 2.0495 (18) to 2.0831 (18) Å, while the Cr-Cl and Cr-(OH2) bond lengths are 2.2734 (7) and 1.9986 (17) Å, respectively. The tetra-hedral [ZnCl4](2-) anion is slightly distorted owing to its involvement in O-H⋯Cl hydrogen bonding with coordinating and non-coordinating water mol-ecules. The two types of water mol-ecules also inter-act through O-H⋯O hydrogen bonds. The observed hydrogen-bonding pattern leads to the formation of a three-dimensional network structure.
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Affiliation(s)
- Dohyun Moon
- Pohang Accelerator Laboratory, POSTECH, Pohang 790-784, Republic of Korea
| | - Jong-Ha Choi
- Department of Chemistry, Andong National University, Andong 760-749, Republic of Korea
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36
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Yu T, Fu Y, Wang Y, Hao P, Shen J, Fu Y. Hierarchical symmetry transfer and flexible charge matching in five [M(phen)3]2+directed iodoargentates with 1 to 3D frameworks. CrystEngComm 2015. [DOI: 10.1039/c5ce01692d] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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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.
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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
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39
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Huang T, Wu X, Weare WW, Sommer RD. Mono-Oxido-Bridged Heterobimetallic and Heterotrimetallic Compounds Containing Titanium(IV) and Chromium(III). Eur J Inorg Chem 2014. [DOI: 10.1002/ejic.201402800] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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40
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Mazumder S, Thomas RA, Lord RL, Schlegel HB, Endicott JF. A density functional theory and spectroscopic study of intramolecular quenching of metal-to-ligand charge-transfer excited states in some mono-bipyridine ruthenium(II) complexes. CAN J CHEM 2014. [DOI: 10.1139/cjc-2014-0155] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The complexes [Ru(NCCH3)4bpy]2+ and [Ru([14]aneS4)bpy]2+ ([14]aneS4 = 1,4,8,11-tetrathiacyclotetradecane, bpy = 2,2′-bipyridine) have similar absorption and emission spectra but the 77 K metal-to-ligand charge-transfer (MLCT) excited state emission lifetime of the latter is less than 0.3% that of the former. Density functional theory modeling of the lowest energy triplet excited states indicates that triplet metal centered (3MC) excited states are about 3500 cm−1 lower in energy than their 3MLCT excited states in both complexes. The differences in excited state lifetimes arise from a much larger coordination sphere distortion for [Ru(NCCH3)4bpy]2+ and the associated larger reorganizational barrier for intramolecular electron transfer. The smaller ruthenium ligand distortions of the [Ru([14]aneS4)bpy]2+ complex are apparently a consequence of stereochemical constraints imposed by the macrocyclic [14]aneS4 ligand, and the 3MC excited state calculated for the unconstrained [Ru(S(CH3)2)4bpy]2+ complex (S(CH3)2 = dimethyl sulfide) is distorted in a manner similar to that of [Ru(NCCH3)4bpy]2+. Despite the lower energy calculated for its 3MC than 3MLCT excited state, [Ru(NCCH3)4bpy]2+ emits strongly in 77 K glasses with an emission quantum yield of 0.47. The emission is biphasic with about a 1 μs lifetime for its dominant (86%) emission component. The 405 nm excitation used in these studies results in a significant amount of photodecomposition in the 77 K glasses. This is a temperature-dependent biphotonic process that most likely involves the bipyridine-radical anionic moiety of the 3MLCT excited state. A smaller than expected value found for the radiative rate constant is consistent with a lower energy 3MC than 3MLCT state.
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Affiliation(s)
- Shivnath Mazumder
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
| | - Ryan A. Thomas
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
| | - Richard L. Lord
- Grand Valley State University, 1 Campus Dr., Allendale, MI 49401-9403, USA
| | | | - John F. Endicott
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
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41
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The application of synchrotron radiation and in particular X-ray absorption spectroscopy to matrix isolated species. Coord Chem Rev 2014. [DOI: 10.1016/j.ccr.2014.05.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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42
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Shen J, Yap GPA, Barker IV WE, Geiger WE, Theopold KH. An electron transfer series of octahedral chromium complexes containing a redox non-innocent α-diimine ligand. Chem Commun (Camb) 2014; 50:10626-9. [DOI: 10.1039/c4cc03332a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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44
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Zell T, Milko P, Fillman KL, Diskin-Posner Y, Bendikov T, Iron MA, Leitus G, Ben-David Y, Neidig ML, Milstein D. Iron Dicarbonyl Complexes Featuring Bipyridine-Based PNN Pincer Ligands with Short Interpyridine CC Bond Lengths: Innocent or Non-Innocent Ligand? Chemistry 2014; 20:4403-13. [DOI: 10.1002/chem.201304631] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Indexed: 11/10/2022]
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45
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Hui AK, Chen CH, Terwilliger AM, Lord RL, Caulton KG. A tale of hydrogen abstraction, initially detected via X-ray diffraction. ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2014; 70:250-5. [PMID: 24594711 DOI: 10.1107/s2053229614003234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 02/12/2014] [Indexed: 11/10/2022]
Abstract
Reaction of a bis-tetrazinyl pyridine pincer ligand, btzp, with a vanadium(III) reagent gives not a simple adduct but dichlorido{3-methyl-6-[6-(6-methyl-1,2,4,5-tetrazin-3-yl-κN(2))pyridin-2-yl-κN]-1,4-dihydro-1,2,4,5-tetrazin-1-yl-κN(1)}oxidovanadium(IV) acetonitrile 2.5-solvate, [V(C11H10N9)Cl2O]·2.5CH3CN, a species which X-ray diffraction reveals to have one H atom added to one of the two tetrazinyl rings. This H atom was first revealed by a short intermolecular N...Cl contact in the unit cell and subsequently established, from difference maps, to be associated with a hydrogen bond. One chloride ligand has also been replaced by an oxide ligand in this synthetic reaction. This formula for the complex, [V(Hbtzp)Cl2O], leaves open the question of both ligand oxidation state and spin state. A computational study of all isomeric locations of the H atom shows the similarity of their energies, which is subject to perturbation by intermolecular hydrogen bonding found in X-ray work on the solid state. These density functional calculations reveal that the isomer with the H atom located as found in the solid state contains a neutral radical Hbtzp ligand and tetravalent d(1) V center, but that these two unpaired electrons are more stable as an open-shell singlet and hence antiferromagnetically coupled.
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Affiliation(s)
- Alice K Hui
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN 47405, USA
| | - Chun Hsing Chen
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN 47405, USA
| | - Adam M Terwilliger
- Department of Chemistry, Grand Valley State University, 1 Campus Drive, 312 Padnos Hall, Allendale, MI 49401, USA
| | - Richard L Lord
- Department of Chemistry, Grand Valley State University, 1 Campus Drive, 312 Padnos Hall, Allendale, MI 49401, USA
| | - Kenneth G Caulton
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN 47405, USA
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46
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Wang M, Weyhermüller T, England J, Wieghardt K. Molecular and Electronic Structures of Six-Coordinate “Low-Valent” [M(Mebpy)3]0 (M = Ti, V, Cr, Mo) and [M(tpy)2]0 (M = Ti, V, Cr), and Seven-Coordinate [MoF(Mebpy)3](PF6) and [MX(tpy)2](PF6) (M = Mo, X = Cl and M = W, X = F). Inorg Chem 2013; 52:12763-76. [DOI: 10.1021/ic402037e] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Mei Wang
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Thomas Weyhermüller
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Jason England
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Karl Wieghardt
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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47
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Kundu S, Maity S, Saha Sardar P, Ghosh S, Ghosh P. Mono- and di-nuclear photoluminescent complexes of zinc(II), cadmium(II) and mercury(II) of a chiral diimine ligand. Dalton Trans 2013; 42:13026-35. [PMID: 23872725 DOI: 10.1039/c3dt51348c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction of α-pyridoin and N-phenyl-o-phenylenediamine affords 2-(2-(phenylamino)phenylimino)-1,2-di(pyridin-2-yl)ethanol (L) which undergoes cyclization to a chiral diimine, 2-methoxy-1-phenyl-2,3-di(pyridin-2-yl)-1,2-dihydroquinoxaline, L(OMe) (conjugated 14πe system) in the presence of zinc(II), cadmium(II) and mercury(II) ions affording [Zn(L(OMe))Cl2] (1), [Cd2(L(OMe))2Cl4] (2) and [Hg2(L(OMe))2Cl4] (3) complexes. Ligand L and complexes 1-3 are substantiated by elemental analyses, mass, IR, (1)H NMR and UV-vis spectra including the single-crystal X-ray structures of 1 and 3. The possibility of the atropisomerism of L is restricted in cyclic L(OMe). L and complexes 1-3 are fluorescent in fluid solutions at 298 K (CH2Cl2: 1, λ(ex) = 470 nm, λ(em) = 627 nm, Φ = 0.014, τ(avg) = 2.5 ns; 2, λ(ex) = 430 nm, λ(em) = 599 nm, Φ = 0.08, τ(avg) = 7.6 ns; 3, λ(ex) = 415 nm, λ(em) = 600 nm, Φ = 0.021, τ(avg) = 2.8 ns). Time-resolved emission spectra (TRES) established that the two-component lifetimes of 1-3 are due to the existence of two conformers. Density functional theory (DFT) and time dependent (TD) DFT calculations authenticated that 1-3 complexes are fluorescent due to intra-ligand charge transfer (ILCT) to the π(diimines)* orbital.
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Affiliation(s)
- Suman Kundu
- Department of Chemistry, R. K. Mission Residential College, Narendrapur, Kolkata 700 103, India.
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48
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England J, Wieghardt K. 2,2′-Bipyridine Compounds of Group 14 Elements: A Density Functional Theory Study. Inorg Chem 2013; 52:10067-79. [DOI: 10.1021/ic401375a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jason England
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36,
D-45470 Mülheim an der Ruhr, Germany
| | - Karl Wieghardt
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36,
D-45470 Mülheim an der Ruhr, Germany
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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.
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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
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50
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Wang M, England J, Weyhermüller T, Kokatam SL, Pollock CJ, DeBeer S, Shen J, Yap GPA, Theopold KH, Wieghardt K. New Complexes of Chromium(III) Containing Organic π-Radical Ligands: An Experimental and Density Functional Theory Study. Inorg Chem 2013; 52:4472-87. [PMID: 23531224 DOI: 10.1021/ic302743s] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Mei Wang
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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