1
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Shephard ACG, Delon A, Chevreux S, Martinez A, Guo Z, Deacon GB, Lemercier G, McClenaghan N, Jonusauskas G, Junk PC, Jaroschik F. Divalent ansa-Octaphenyllanthanocenes: Synthesis, Structures, and Eu II Luminescence. Inorg Chem 2024; 63:9395-9405. [PMID: 37310150 DOI: 10.1021/acs.inorgchem.3c01062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Reductive dimerization of fulvenes using low-valent metal precursors is a straightforward one-step approach to access ethylene-bridged metallocenes. This process has so far mainly been employed with fulvenes carrying one or two substituents in the exocyclic position. In this work, a new synthesis of the unsubstituted exocyclic 1,2,3,4-tetraphenylfulvene (1), its full structural characterization by NMR spectroscopy and single-crystal X-ray diffraction, as well as some photophysical properties and its first use in reductive dimerization are described. This fulvene reacted with different lanthanoid metals in thf to provide the divalent ansa-octaphenylmetallocenes [Ln(C5Ph4CH2)2(thf)n] (Ln = Sm, n = 2 (2); Ln = Eu, n = 2 (3); and Ln = Yb, n = 1 (4)). These complexes were characterized by X-ray diffraction, laser desorption/ionization time of flight mass spectrometry, and, in the case of Sm and Yb, multinuclear NMR spectroscopy, showing the influence of the ansa-bridge on solution and solid-state structures compared to previously reported unbridged metallocenes. Furthermore, the luminescence properties of the Eu ansa complex 3 were studied in solution and the solid state, revealing significant differences with the known octa- and deca-phenyleuropocenes, [Eu(C5Ph4H)2(dme)] and [Eu(C5Ph5)2].
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Affiliation(s)
- Angus C G Shephard
- College of Science and Engineering, James Cook University, Townsville 4811, Australia
| | - Aymeric Delon
- College of Science and Engineering, James Cook University, Townsville 4811, Australia
- Université de Reims Champagne-Ardenne, ICMR, UMR 7312, Reims 56187, France
| | - Sylviane Chevreux
- Université de Reims Champagne-Ardenne, ICMR, UMR 7312, Reims 56187, France
| | - Agathe Martinez
- Université de Reims Champagne-Ardenne, ICMR, UMR 7312, Reims 56187, France
| | - Zhifang Guo
- College of Science and Engineering, James Cook University, Townsville 4811, Australia
| | - Glen B Deacon
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
| | - Gilles Lemercier
- Université de Reims Champagne-Ardenne, ICMR, UMR 7312, Reims 56187, France
| | - Nathan McClenaghan
- Université Bordeaux, CNRS, Bordeaux INP, ISM, UMR 5255, Talence F-33400, France
| | | | - Peter C Junk
- College of Science and Engineering, James Cook University, Townsville 4811, Australia
| | - Florian Jaroschik
- ICGM, Université Montpellier, CNRS, ENSCM, Montpellier 34090, France
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2
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Bokouende SS, Kulasekara DN, Worku SA, Ward CL, Kajjam AB, Lutter JC, Allen MJ. Expanding the Coordination of f-Block Metals with Tris[2-(2-methoxyethoxy)ethyl]amine: From Molecular Complexes to Cage-like Structures. Inorg Chem 2024; 63:9434-9450. [PMID: 38016147 PMCID: PMC11129929 DOI: 10.1021/acs.inorgchem.3c02752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
Low-valent f-block metals have intrinsic luminescence, electrochemical, and magnetic properties that are modulated with ligands, causing the coordination chemistry of these metals to be imperative to generating critical insights needed to impact modern applications. To this end, we synthesized and characterized a series of twenty-seven complexes of f-metal ions including EuII, YbII, SmII, and UIII and hexanuclear clusters of LaIII and CeIII to study the impact of tris[2-(2-methoxyethoxy)ethyl]amine, a flexible acyclic analogue of the extensively studied 2.2.2-cryptand, on the coordination chemistry and photophysical properties of low-valent f-block metals. We demonstrate that the flexibility of the ligand enables luminescence tunability over a greater range than analogous cryptates of EuII in solution. Furthermore, the ligand also displays a variety of binding modes to f-block metals in the solid state that are inaccessible to cryptates of low-valent f-block metals. In addition to serving as a ligand for f-block metals of various sizes and oxidation states, tris[2-(2-methoxyethoxy)ethyl]amine also deprotonates water molecules coordinated to trivalent triflate salts of f-block metal ions, enabling the isolation of hexanuclear clusters containing either LaIII or CeIII. The ligand was also found to bind more tightly to YbII and UIII in the solid state compared to 2.2.2-cryptand, suggesting that it can play a role in the isolation of other low-valent f-block metals such CfII, NpIII, and PuIII. We expect that our findings will inspire applications of tris[2-(2-methoxyethoxy)ethyl]amine in the design of light-emitting diodes and the synthesis of extremely reducing divalent f-block metal complexes that are of interest for a wide range of applications.
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Affiliation(s)
- Sergely Steephen Bokouende
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - D Nuwangi Kulasekara
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Sara A Worku
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Cassandra L Ward
- Lumigen Instrument Center, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Aravind B Kajjam
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Jacob C Lutter
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Matthew J Allen
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
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3
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Ouellette ET, Brackbill IJ, Kynman AE, Christodoulou S, Maron L, Bergman RG, Arnold J. Triple Inverse Sandwich versus End-On Diazenido: Bonding Motifs across a Series of Rhenium-Lanthanide and -Actinide Complexes. Inorg Chem 2024; 63:7177-7188. [PMID: 38598523 DOI: 10.1021/acs.inorgchem.3c04248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
While synthesizing a series of rhenium-lanthanide triple inverse sandwich complexes, we unexpectedly uncovered evidence for rare examples of end-on lanthanide dinitrogen coordination for certain heavy lanthanide elements as well as for uranium. We begin our report with the synthesis and characterization of a series of trirhenium triple inverse sandwich complexes with the early lanthanides, Ln[(μ-η5:η5-Cp)Re(BDI)]3(THF) (1-Ln, Ln = La, Ce, Pr, Nd, Sm; Cp = cyclopentadienide, BDI = N,N'-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate). However, as we moved across the lanthanide series, we ran into an unexpected result for gadolinium in which we structurally characterized two products for gadolinium, namely, 1-Gd (analogous to 1-Ln) and a diazenido dirhenium double inverse sandwich complex Gd[(μ-η1:η1-N2)Re(η5-Cp)(BDI)][(μ-η5:η5-Cp)Re(BDI)]2(THF)2 (2-Gd). Evidence for analogues of 2-Gd was spectroscopically observed for other heavy lanthanides (2-Ln, Ln = Tb, Dy, Er), and, in the case of 2-Er, structurally authenticated. These complexes represent the first observed examples of heterobimetallic end-on lanthanide dinitrogen coordination. Density functional theory (DFT) calculations were utilized to probe relevant bonding interactions and reveal energetic differences between both the experimental and putative 1-Ln and 2-Ln complexes. We also present additional examples of novel end-on heterobimetallic lanthanide and actinide diazenido moieties in the erbium-rhenium complex (η8-COT)Er[(μ-η1:η1-N2)Re(η5-Cp)(BDI)](THF)(Et2O) (3-Er) and uranium-rhenium complex [Na(2.2.2-cryptand)][(η5-C5H4SiMe3)3U(μ-η1:η1-N2)Re(η5-Cp)(BDI)] (4-U). Finally, we expand the scope of rhenium inverse sandwich coordination by synthesizing divalent double inverse sandwich complex Yb[(μ-η5:η5-Cp)Re(BDI)]2(THF)2 (5-Yb), as well as base-free, homoleptic rhenium-rare earth triple inverse sandwich complex Y[(μ-η5:η5-Cp)Re(BDI)]3 (6-Y).
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Affiliation(s)
- Erik T Ouellette
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - I Joseph Brackbill
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Amy E Kynman
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Stella Christodoulou
- LPCNO, Université de Toulouse, INSA Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
| | - Laurent Maron
- LPCNO, Université de Toulouse, INSA Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
| | - Robert G Bergman
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - John Arnold
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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4
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Tomar M, Bhimpuria R, Kocsi D, Thapper A, Borbas KE. Photocatalytic Generation of Divalent Lanthanide Reducing Agents. J Am Chem Soc 2023; 145:22555-22562. [PMID: 37796974 PMCID: PMC10591332 DOI: 10.1021/jacs.3c07508] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Indexed: 10/07/2023]
Abstract
Divalent lanthanide (Ln) compounds are excellent reducing agents with unique reactivity profiles. These reagents are typically used in superstoichiometric amounts, often in combination with harmful additives. Reactions catalytic in Ln(II) reagents that retain the reactivity and selectivity of the stoichiometric transformations are currently lacking due to the absence of effective and selective methods to form reactive Ln(II) species from stable precursors. Here, active Ln(II) is generated from a Ln(III) precursor through reduction by a photoexcited coumarin or carbostyril chromophore, which, in turn, is regenerated by a sacrificial reductant. The reductant can be metallic (Zn) or organic (amines) and can be used in strictly stoichiometric amounts. A broad range of reactions, including C-halogen, C═C, C═X (X = O, N), P═O, and N═N reductions, as well as C-C, C-X (X = N, S, P), and N-N couplings were readily carried out in yields and selectivities comparable to or better than those afforded by the analogous stoichiometric transformations. The reaction outcomes could be altered by changing the ligand or the lanthanide or through the addition of environmentally benign additives (e.g., water). EPR spectroscopy supported the formation of both Ln(II) and oxidized chromophore intermediates. Taken together, these results establish photochemical Ln(II) generation as a powerful strategy for rendering Ln(II)-mediated reactions catalytic.
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Affiliation(s)
| | | | - Daniel Kocsi
- Department of Chemistry,
Ångström Laboratory, Uppsala
University, Uppsala 75120, Sweden
| | - Anders Thapper
- Department of Chemistry,
Ångström Laboratory, Uppsala
University, Uppsala 75120, Sweden
| | - K. Eszter Borbas
- Department of Chemistry,
Ångström Laboratory, Uppsala
University, Uppsala 75120, Sweden
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5
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Hay MA, Gable RW, Boskovic C. Modulating the electronic properties of divalent lanthanoid complexes with subtle ligand tuning. Dalton Trans 2023; 52:3315-3324. [PMID: 36806851 DOI: 10.1039/d2dt03782c] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Five new compounds of formula [LnII(Mentpa)2](BPh4)2 (Ln = Eu, n = 0 (1-Eu), n = 2 (2-Eu) and n = 3 (3-Eu); Ln = Yb, n = 0 (1-Yb) and n = 2 (2-Yb); tpa = tris(2-pyridylmethyl)amine, n = 0-3 corresponds to successive methylation of the 6-position of the pyridine rings of Mentpa) have been synthesized and their structural, photophysical and electrochemical properties investigated. The LnII ions in the five complexes possess cubic coordination geometry and exhibit only small structural differences, due to the lengthening of the Ln-N bonds to accommodate the additional steric bulk associated with increasing methylation of the Mentpa ligands. Photophysical studies indicate moderate shifts in absorbance, emission and excitation bands associated with the 4f7 ↔ 4f65d1 (EuII) and 4f14 ↔ 4f135d1 (YbII) transitions, while electrochemistry reveals modulation of the redox potential of the LnII to LnIII oxidation. There is a strong correlation between Ln-N bond lengths and both the photophysical transition energies and metal redox-potentials, revealing how subtle ligand changes and ligand field effects can be used to modulate the electronic properties of complexes of divalent lanthanoid ions. Utilization of these insights may ultimately afford design and property tuning strategies for future functional molecular complexes based on divalent lanthanoid metals.
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Affiliation(s)
- Moya A Hay
- School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Robert W Gable
- School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Colette Boskovic
- School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia.
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6
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Mahieu N, Piątkowski J, Simler T, Nocton G. Back to the future of organolanthanide chemistry. Chem Sci 2023; 14:443-457. [PMID: 36741512 PMCID: PMC9848160 DOI: 10.1039/d2sc05976b] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 11/29/2022] [Indexed: 12/02/2022] Open
Abstract
At the dawn of the development of structural organometallic chemistry, soon after the discovery of ferrocene, the description of the LnCp3 complexes, featuring large and mostly trivalent lanthanide ions, was rather original and sparked curiosity. Yet, the interest in these new architectures rapidly dwindled due to the electrostatic nature of the bonding between π-aromatic ligands and 4f-elements. Almost 70 years later, it is interesting to focus on how the discipline has evolved in various directions with the reports of multiple catalytic reactivities, remarkable potential in small molecule activation, and the development of rich redox chemistry. Aside from chemical reactivity, a better understanding of their singular electronic nature - not precisely as simplistic as anticipated - has been crucial for developing tailored compounds with adapted magnetic anisotropy or high fluorescence properties that have witnessed significant popularity in recent years. Future developments shall greatly benefit from the detailed reactivity, structural and physical chemistry studies, particularly in photochemistry, electro- or photoelectrocatalysis of inert small molecules, and manipulating the spins' coherence in quantum technology.
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Affiliation(s)
- Nolwenn Mahieu
- LCM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Route de Saclay91120 PalaiseauFrance
| | - Jakub Piątkowski
- LCM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Route de Saclay91120 PalaiseauFrance
| | - Thomas Simler
- LCM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Route de Saclay91120 PalaiseauFrance
| | - Grégory Nocton
- LCM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Route de Saclay91120 PalaiseauFrance
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7
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Synthesis and luminescent properties of new molecular compounds of divalent lanthanides LnCl2∙0.5H2O (Ln = Yb, Sm, Tm, and Eu). J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2023.114559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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8
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Barraza R, Sertage AG, Kajjam AB, Ward CL, Lutter JC, Schlegel HB, Allen MJ. Properties of Amine-Containing Ligands That Are Necessary for Visible-Light-Promoted Catalysis with Divalent Europium. Inorg Chem 2022; 61:19649-19657. [PMID: 36417708 PMCID: PMC9771976 DOI: 10.1021/acs.inorgchem.2c02911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We describe a study of the influence of amine-containing ligands on the photoredox-relevant properties of EuII toward the rational design of EuII-containing catalysts for visible-light-promoted photoredox reactions. We report our observations of the effects of the degree of functionalization of amines, denticity, and macrocylic ligands on the absorbance of EuII. Ligands that contain secondary amines bathochromically shift the absorbance of EuCl2 relative to ligands that contain primary or tertiary amines. Similarly, ligands of larger denticity have a larger bathochromic shift of the absorbance than ligands of smaller denticity. We observed that macrocyclic ligands have a larger effect on the absorbance of EuCl2 than nonmacrocyclic ligands. Also, we report the photoredox reactivity of four new EuII-containing complexes. These observations are potentially influential in understanding the ligand properties that promote the use of EuII in visible-light-promoted photoredox catalysis.
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Affiliation(s)
- Ramiro Barraza
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, United States
| | - Alexander G. Sertage
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, United States
| | - Aravind B. Kajjam
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, United States
| | - Cassandra L. Ward
- Lumigen Instrument Center, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, United States
| | - Jacob C. Lutter
- Department of Chemistry and Biochemistry, University of Southern Indiana, 8600 University Blvd, Evansville, IN 47712, United States
| | - H. Bernhard Schlegel
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, United States
| | - Matthew J. Allen
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, United States,Corresponding Author
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9
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Kynman AE, Elghanayan LK, Desnoyer AN, Yang Y, Sévery L, Di Giuseppe A, Tilley TD, Maron L, Arnold PL. Controlled monodefluorination and alkylation of C(sp 3)-F bonds by lanthanide photocatalysts: importance of metal-ligand cooperativity. Chem Sci 2022; 13:14090-14100. [PMID: 36540817 PMCID: PMC9728647 DOI: 10.1039/d2sc04192h] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 11/05/2022] [Indexed: 08/01/2023] Open
Abstract
The controlled functionalization of a single fluorine in a CF3 group is difficult and rare. Photochemical C-F bond functionalization of the sp3-C-H bond in trifluorotoluene, PhCF3, is achieved using catalysts made from earth-abundant lanthanides, (CpMe4)2Ln(2-O-3,5- t Bu2-C6H2)(1-C{N(CH)2N(iPr)}) (Ln = La, Ce, Nd and Sm, CpMe4 = C5Me4H). The Ce complex is the most effective at mediating hydrodefluorination and defluoroalkylative coupling of PhCF3 with alkenes; addition of magnesium dialkyls enables catalytic C-F bond cleavage and C-C bond formation by all the complexes. Mechanistic experiments confirm the essential role of the Lewis acidic metal and support an inner-sphere mechanism of C-F activation. Computational studies agree that coordination of the C-F substrate is essential for C-F bond cleavage. The unexpected catalytic activity for all members is made possible by the light-absorbing ability of the redox non-innocent ligands. The results described herein underscore the importance of metal-ligand cooperativity, specifically the synergy between the metal and ligand in both light absorption and redox reactivity, in organometallic photocatalysis.
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Affiliation(s)
- Amy E Kynman
- Department of Chemistry, University of California, Berkeley Berkeley CA 94720-1460 USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
| | - Luca K Elghanayan
- Department of Chemistry, University of California, Berkeley Berkeley CA 94720-1460 USA
| | - Addison N Desnoyer
- Department of Chemistry, University of California, Berkeley Berkeley CA 94720-1460 USA
| | - Yan Yang
- LPCNO, Université de Toulouse 135 Avenue de Rangueil 31077 Toulouse France
| | - Laurent Sévery
- Department of Chemistry, University of California, Berkeley Berkeley CA 94720-1460 USA
| | - Andrea Di Giuseppe
- Department of Chemistry, University of California, Berkeley Berkeley CA 94720-1460 USA
| | - T Don Tilley
- Department of Chemistry, University of California, Berkeley Berkeley CA 94720-1460 USA
| | - Laurent Maron
- LPCNO, Université de Toulouse 135 Avenue de Rangueil 31077 Toulouse France
| | - Polly L Arnold
- Department of Chemistry, University of California, Berkeley Berkeley CA 94720-1460 USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
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10
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Chen J, Carpenter SH, Fetrow TV, Mengell J, Kirk ML, Tondreau AM. Magnetism Studies of Bis(acyl)phosphide-Supported Eu 3+ and Eu 2+ Complexes. Inorg Chem 2022; 61:18466-18475. [DOI: 10.1021/acs.inorgchem.2c02675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Ju Chen
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico87131, United States
| | | | - Taylor V. Fetrow
- Los Alamos National Laboratory, Los Alamos, New Mexico87545, United States
| | - Joshua Mengell
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico87131, United States
| | - Martin L. Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico87131, United States
- The Center for High Technology Materials, The University of New Mexico, Albuquerque, New Mexico87106, United States
- The Center for Quantum Information and Control (CQuIC), The University of New Mexico, Albuquerque, New Mexico87131, United States
| | - Aaron M. Tondreau
- Los Alamos National Laboratory, Los Alamos, New Mexico87545, United States
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11
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Zhang J, Yang X, Wang W, Jia D. Highly-visible-light-driven photocatalysts based on terbium(III) complexes with tetraselenidoantimonate and polyamine mixed ligands. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.110185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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12
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Dembowski M, Rowley JE, Boland K, Droessler J, Hathcoat DA, Marchi A, Goff GS, May I. Rare earth element separations by high-speed counter-current chromatography. J Chromatogr A 2022; 1682:463528. [PMID: 36179601 DOI: 10.1016/j.chroma.2022.463528] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 11/17/2022]
Abstract
Following the initial development of High-Speed Counter-Current Chromatography (HSCCC) in the 1960s, several studies have explored its applicability in the separation of rare earth elements (REEs). More recently, however, HSCCC publications have transitioned towards the separation of natural products or pharmaceuticals, leaving the application for REEs largely unexplored from a practical standpoint. Herein, we expand upon prior work in this field by evaluating the suitability of HSCCC to separation of a subset of non-radioactive REEs (Nd, Sm, Eu, Tb, and Y) at 10-4 mol levels using di-(2-ethylhexyl)phosphoric acid (HDEHP) in n-heptane as the stationary phase and hydrochloric acid as the mobile phase. First, the effect of flow rate on the stationary phase volume retention ratio and resolution of Nd/Sm/Eu subgroup was evaluated followed by optimization of step-gradient elution profiles resulting in additional recovery of Tb and Y within a seven-hour window. The five REEs were separated at the baseline resolution level or above. Elution profiles obtained from multiple runs across two independently operated columns and across independent runs were cross analyzed. Reproducibility in elution profiles point to future applications in radioelement separation chemistry, where both chemical and radiochemical purity are of importance.
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Affiliation(s)
| | - John E Rowley
- Los Alamos National Laboratory, Los Alamos, NM 87545, Mexico
| | - Kevin Boland
- Los Alamos National Laboratory, Los Alamos, NM 87545, Mexico
| | | | | | | | - George S Goff
- Los Alamos National Laboratory, Los Alamos, NM 87545, Mexico
| | - Iain May
- Los Alamos National Laboratory, Los Alamos, NM 87545, Mexico
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13
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Higgins RF, Ruoff KP, Kumar A, Schelter EJ. Coordination Chemistry-Driven Approaches to Rare Earth Element Separations. Acc Chem Res 2022; 55:2616-2627. [PMID: 36041177 DOI: 10.1021/acs.accounts.2c00312] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Current projections for global mining indicate that unsustainable practices will cause supply problems for many elements, called critical raw materials, in the next 20 years. These include elements necessary for renewable technologies as well as artisanal sources. Energy critical elements (ECEs) comprise a group used for clean, renewable energy applications that are in low abundance in the Earth's crust or require an economic premium to extract from ores. Sustainable practices of acquiring ECEs is an important problem to address through fundamental research to provide alternative energy technologies such as wind turbines and electric vehicles at cheaper costs for our global energy generation and usage. Some of these green technologies incorporate rare-earth (RE) metals (Sc, Y and the lanthanides), which are challenging to separate from mineral sources because of their similar sizes (i.e., ionic radii) and chemical properties. The current process used to provide REs at requisite purities for these applications is counter-current solvent-solvent extraction, which is scalable and works efficiently for any ore composition. However, this method produces large amounts of caustic waste that is environmentally damaging, especially to areas in China that house major separation facilities. Advancement of the selectivity of this process is challenging since exact molecular speciation that affords separations is still relatively unknown. In this context, we developed a program to investigate new RE separations systems that were aimed at minimizing solvent use, controlled by molecular speciation, and could be targeted at problems in recycling these critical metals.The first ligand system that was developed to impart solubility differences between light and heavy rare-earth ions was [{(2-tBuNO)C6H4CH2}3N]3- (TriNOx3-) (graphic below). A differential solubility allowed for a separation of Nd and Dy of SFNd:Dy = ∼300 in a single step. In other words, a 50:50 Nd/Dy sample was enriched to give 95% pure Nd and Dy through a simple filtration, which is potentially impactful to recycling magnetic materials found in wind turbines. This separations system compares favorably to other state-of-the-art molecular extractants that are based on energetic differences of the thermodynamic parameter to affect separations for neighboring elements. This straightforward, thermodynamically driven method to separate REs primed our future research for new coordination chemistry approaches to separations.Another separations system was accomplished through the variable rate of a redox event from one arm of the TriNOx3- ligand. It was determined that the rate of this one electron oxidation, which operated through an electrochemical-chemical-electrochemical mechanism, was dependent on the identity of the RE ion. This kinetically driven separation afforded a separation factor (SF) of SFEu:Y = 75. We have also described other transformations such as ligand exchange, substituent dependent, and redox-driven chelation processes with well-defined speciation to afford purified RE materials. Recently, we determined that magnetic properties can be used to enhance both thermodynamic and kinetic RE separations processes to give an approximately 100% boost for pairs of paramagnetic/diamagnetic REs. These results have shown that both thermodynamic and kinetic RE separations were efficient for different selected RE binary pairs through coordination chemistry. The focus of this Account will detail the differences that are observed for RE separations when promoted by thermodynamic or kinetic factors. Overall, the development of rationally adjusted speciation of REs provides a basis for future industrial separations processes for technologies applied to ECEs derived from wind turbines, batteries for electric vehicles, and LEDs.
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Affiliation(s)
- Robert F Higgins
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 S. 34th St., Philadelphia, Pennsylvania 19104, United States
| | - Kevin P Ruoff
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 S. 34th St., Philadelphia, Pennsylvania 19104, United States
| | - Amit Kumar
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 S. 34th St., Philadelphia, Pennsylvania 19104, United States
| | - Eric J Schelter
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 S. 34th St., Philadelphia, Pennsylvania 19104, United States
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14
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Matsuda S, Nakashima N, Yokoyama K, Taniguchi S, Chosrowjan H, Somekawa T, Yatsuhashi T. Laser-fluence dependence of resonance-enhanced multiphoton reduction of trivalent europium. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Abstract
Coordination-induced bond weakening is a phenomenon wherein ligand X-H bond homolysis occurs in concert with the energetically favorable oxidation of a coordinating metal complex. The coupling of these two processes enables thermodynamically favorable proton-coupled electron transfer reductions to form weak bonds upon formal hydrogen atom transfer to substrates. Moreover, systems utilizing coordination-induced bond weakening have been shown to facilitate the dehydrogenation of feedstock molecules including water, ammonia, and primary alcohols under mild conditions. The formation of exceptionally weak substrate X-H bonds via small molecule homolysis is a powerful strategy in synthesis and has been shown to enable nitrogen fixation under mild conditions. Coordination-induced bond weakening has also been identified as an integral process in biophotosynthesis and has promising applications in renewable chemical fuel storage systems. This review presents a discussion of the advances made in the study of coordination-induced bond weakening to date. Because of the broad range of metal and ligand species implicated in coordination-induced bond weakening, each literature report is discussed individually and ordered by the identity of the low-valent metal. We then offer mechanistic insights into the basis of coordination-induced bond weakening and conclude with a discussion of opportunities for further research into the development and applications of coordination-induced bond weakening systems.
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Affiliation(s)
- Nicholas G Boekell
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Robert A Flowers
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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16
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Bokouende SS, Jenks TC, Ward CL, Allen MJ. Solid-state and solution-phase characterization of Sm II-aza[2.2.2]cryptate and its methylated analogue. Dalton Trans 2022; 51:10852-10855. [PMID: 35781473 PMCID: PMC9650674 DOI: 10.1039/d2dt01823c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two new SmII-azacryptates are reported that differ in steric hindrance and Lewis basicity of donor atoms. The sterically hindered complex has a smaller coordination number and a more negative electrochemical potential than the complex with less steric hindrance.
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Affiliation(s)
| | - Tyler C Jenks
- Deparptment of Chemistry, Wayne State University, 5101 Cass Ave., Detroit, MI 48202, USA.
| | - Cassandra L Ward
- Lumigen Instrument Center, Wayne State University, 5101 Cass Ave., Detroit, MI 48202, USA
| | - Matthew J Allen
- Deparptment of Chemistry, Wayne State University, 5101 Cass Ave., Detroit, MI 48202, USA.
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17
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Willauer AR, Fadaei-Tirani F, Zivkovic I, Sienkiewicz A, Mazzanti M. Structure and Reactivity of Polynuclear Divalent Lanthanide Disiloxanediolate Complexes. Inorg Chem 2022; 61:7436-7447. [PMID: 35505299 DOI: 10.1021/acs.inorgchem.2c00479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Trinuclear molecular complexes of europium (II) and ytterbium(II) [Ln3{(Ph2SiO)2O}3(THF)6], 1-Ln3L3 (Ln = Eu and Yb), supported by the dianionic tetraphenyl disiloxanediolate ligand, were synthesized via protonolysis of the [Ln{N(SiMe3)2}2(THF)2] complexes. In contrast, the reaction of [Sm{N(SiMe3)2}2(THF)2] with the (Ph2SiOH)2O ligand led to the isolation of the mixed-valent Sm(II)/Sm(III) complex [Sm3{(Ph2SiO)2O}3{N(SiMe3)2}(THF)4], 2-Sm3L3, which was crystallographically characterized. The Eu(II) complex 1-Eu3L3 displays weak ferromagnetic coupling between the Eu(II) metal centers (J = 0.1035 cm-1). The addition of 3 equiv of (Ph2SiOK)2O to 1-Eu3L3 resulted in the formation of the polynuclear Eu(II) dimer of dimers [K4Eu2{(Ph2SiO)2O}4(Et2O)2]2, 3-Eu2L4. Complexes 1-Ln3L3 (Ln = Eu and Yb) are stable in solution at room temperature, while 3-Eu2L4 shows higher reactivity and rapidly decomposes to give the mixed-valent Eu(II)/Eu(III) species [K3Eu2{(Ph2SiO)2O}4], 4-Eu2L4. Complex 1-Yb3L3 affects the slow reductive disproportionation of carbon dioxide, but 1-Eu3L3 does not display any reactivity toward CO2. However, the presence of one additional (Ph2SiO-)2O per Eu(II) metal center in 3-Eu2L4 increases dramatically the reductive ability of the Eu(II) metal centers, affording the first example of carbon dioxide activation by an isolated divalent europium complex. The reduction of CO2 by 3-Eu2L4 is immediate, and carbonate is formed selectively after the addition of a stoichiometric amount of CO2.
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Affiliation(s)
- Aurélien R Willauer
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Farzaneh Fadaei-Tirani
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Ivica Zivkovic
- Laboratory for Quantum Magnetism, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Andrzej Sienkiewicz
- Laboratory for Quantum Magnetism, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.,ADSresonances Sàrl; Route de Genève 60B, 1028 Préverenges, Switzerland
| | - Marinella Mazzanti
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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18
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Denisenko YG, Sedykh AE, Oreshonkov AS, Molokeev MS, Azarapin NO, Sal'nikova EI, Chimitova OD, Andreev OV, Razumkova IA, Müller‐Buschbaum K. Europium (II) Sulfate EuSO
4
: Synthesis Methods, Crystal and Electronic Structure, Luminescence Properties. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202200043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Yuriy G. Denisenko
- Department of General and Special Chemistry Industrial University of Tyumen Tyumen 625000 Russia
- Institute of Inorganic and Analytical Chemistry Justus-Liebig-University of Giessen 35392 Giessen Germany
- Department of Inorganic and Physical Chemistry Tyumen State University Tyumen 625003 Russia
| | - Alexander E. Sedykh
- Institute of Inorganic and Analytical Chemistry Justus-Liebig-University of Giessen 35392 Giessen Germany
| | - Aleksandr S. Oreshonkov
- Laboratory of Molecular Spectroscopy Kirensky Institute of Physics Federal Research Center KSC SB RAS Krasnoyarsk 660036 Russia
- School of Engineering and Construction Siberian Federal University Krasnoyarsk 660041 Russia
| | - Maxim S. Molokeev
- Institute of Engineering Physics and Radioelectronics Siberian Federal University Krasnoyarsk 660041 Russia
- Laboratory of Crystal Physics Kirensky Institute of Physics Federal Research Center KSC SB RAS Krasnoyarsk 660036 Russia
- Research and Development Department Kemerovo State University Kemerovo 650000 Russia
| | - Nikita O. Azarapin
- Department of Inorganic and Physical Chemistry Tyumen State University Tyumen 625003 Russia
| | - Elena I. Sal'nikova
- Department of Inorganic and Physical Chemistry Tyumen State University Tyumen 625003 Russia
- Research Department Northern Trans-Ural Agricultural University Tyumen 625003 Russia
| | | | - Oleg V. Andreev
- Department of Inorganic and Physical Chemistry Tyumen State University Tyumen 625003 Russia
- Laboratory of the Chemistry of Rare Earth Compounds Institute of Solid State Chemistry, UB RAS Ekaterinburg 620137 Russia
| | - Illaria A. Razumkova
- Department of Inorganic and Physical Chemistry Tyumen State University Tyumen 625003 Russia
| | - Klaus Müller‐Buschbaum
- Institute of Inorganic and Analytical Chemistry Justus-Liebig-University of Giessen 35392 Giessen Germany
- Center for Materials Research (LaMa) Justus-Liebig-University of Giessen Heinrich-Buff-Ring 16 35392 Gießen Germany
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19
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Yan W, Li T, Cai Z, Qi H, Guo R, Huo P, Liu Z, Bian Z. Systematic tuning of the emission colors and redox potential of Eu( ii)-containing cryptates by changing the N/O ratio of cryptands. Inorg Chem Front 2022. [DOI: 10.1039/d2qi01216b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The λmax, excited-state lifetimes, and the anodic peak potential of Eu2+/Eu3+ for Eu(ii)-containing cryptates depend linearly on the number of N atoms.
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Affiliation(s)
- Wenchao Yan
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Tingzhou Li
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Zelun Cai
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Hao Qi
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Ruoyao Guo
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Peihao Huo
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Zhiwei Liu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Zuqiang Bian
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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20
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Prieto A, Jaroschik F. Recent Applications of Rare Earth Complexes in Photoredox Catalysis for Organic
Synthesis. CURR ORG CHEM 2022. [DOI: 10.2174/1385272825666211126123928] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
:
In recent years, photoredox catalysis has appeared as a new paradigm for forging a
wide range of chemical bonds under mild conditions using abundant reagents. This approach
allows many organic transformations through the generation of various radical species, enabling
the valorization of non-traditional partners. A continuing interest has been devoted to
the discovery of novel radical-generating procedures. Over the last ten years, strategies using
rare-earth complexes as either redox-active centers or as redox-neutral Lewis acids have
emerged. This review provides an overview of the recent accomplishments made in this field.
It especially aims to demonstrate the utility of rare-earth complexes for ensuring photocatalytic
transformations and to inspire future developments.
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Affiliation(s)
- Alexis Prieto
- ICGM, Univ Montpellier, CNRS, ENSCM, Montpellier, France
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21
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Starck M, Fradgley JD, De Rosa DF, Batsanov AS, Papa M, Taylor MJ, Lovett JE, Lutter JC, Allen MJ, Parker D. Versatile Para-Substituted Pyridine Lanthanide Coordination Complexes Allow Late Stage Tailoring of Complex Function. Chemistry 2021; 27:17921-17927. [PMID: 34705302 PMCID: PMC8688332 DOI: 10.1002/chem.202103243] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Indexed: 12/28/2022]
Abstract
A series of cationic and neutral p-Br and p-NO2 pyridine substituted Eu(III) and Gd(III) coordination complexes serve as versatile synthetic intermediates. Nucleophilic aromatic substitution occurs readily at the para position under mild conditions, allowing C-N and C-C bond forming reactions to take place, permitting the introduction of azide, amino and alkynyl substituents. For Eu(III) complexes, this approach allows late stage tuning of absorption and emission spectral properties, exemplified by the lowering of the energy of an LMCT transition accompanied by a reduction in the Eu-Npy bond length. Additionally, these complexes provide direct access to the corresponding Eu(II) analogues. With the Gd(III) series, the nature of the p-substituent does not significantly change the EPR properties (linewidth, relaxation times), as required for their development as EPR spin probes that can be readily conjugated to biomolecules under mild conditions.
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Affiliation(s)
- Matthieu Starck
- Department of ChemistryDurham UniversitySouth RoadDurhamDH1 3LEUK
| | - Jack D. Fradgley
- Department of ChemistryDurham UniversitySouth RoadDurhamDH1 3LEUK
| | | | | | - Maria Papa
- SUPASchool of Physics and Astronomy and BSRCUniversity of St AndrewsNorth HaughSt AndrewsKY16 9SSUK
| | - Michael J. Taylor
- SUPASchool of Physics and Astronomy and BSRCUniversity of St AndrewsNorth HaughSt AndrewsKY16 9SSUK
| | - Janet E. Lovett
- SUPASchool of Physics and Astronomy and BSRCUniversity of St AndrewsNorth HaughSt AndrewsKY16 9SSUK
| | - Jacob C. Lutter
- Department of ChemistryWayne State University5101 Cass AvenueDetroitMI 48202USA
| | - Matthew J. Allen
- Department of ChemistryWayne State University5101 Cass AvenueDetroitMI 48202USA
| | - David Parker
- Department of ChemistryDurham UniversitySouth RoadDurhamDH1 3LEUK
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22
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Ilichev VA, Silantyeva LI, Rogozhin AF, Yablonskiy AN, Andreev BA, Rumyantsev RV, Fukin GK, Bochkarev MN. Luminescence thermochromism in novel mixed Eu(II)-Cu(I) iodide. Dalton Trans 2021; 50:14244-14251. [PMID: 34553198 DOI: 10.1039/d1dt02384e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new mixed Eu(II)-Cu(I) iodide [Eu(DME)4][Cu2I4] (1) was synthesized by the reaction of an organosulphide salt of Eu(II) and CuI in DME media. X-ray analysis revealed that 1 is an ate-complex consisting of Eu(DME)4 dications and tetraiododicuprate dianions. Upon UV light excitation (λ = 365 nm), the compound exhibits intense double-peaked photoluminescence (PL) at 445 and 500 nm. The relative intensity of these peaks changes dramatically when the temperature changes in the range of 180-250 K. To understand the nature of the found PL thermochromism, the structure and time-resolved PL of 1 were studied at various temperatures. The time-resolved PL studies of 1 at various temperatures revealed the presence of two luminescent centers which are excited by the capture of an electron from the conduction band. The ratio of intensities at 445 and 500 nm (R = I445/I500) in the PL spectra of 1 changes by almost two orders of magnitude and the relative sensitivity S (S = (∂R/∂T)/R) exceeds 5% per K in the range of 190-245 K that makes this compound a promising luminescent thermometer for the range where ammonia exists in a liquid state.
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Affiliation(s)
- Vasily A Ilichev
- G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Tropinina 49, 603950 Nizhny Novgorod, Russian Federation.
| | - Liubov I Silantyeva
- G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Tropinina 49, 603950 Nizhny Novgorod, Russian Federation.
| | - Anton F Rogozhin
- G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Tropinina 49, 603950 Nizhny Novgorod, Russian Federation.
| | - Artem N Yablonskiy
- Institute for Physics of Microstructures of Russian Academy of Sciences, 7 ul. Akademicheskaya, 603950 Nizhny Novgorod, Russian Federation
| | - Boris A Andreev
- Institute for Physics of Microstructures of Russian Academy of Sciences, 7 ul. Akademicheskaya, 603950 Nizhny Novgorod, Russian Federation
| | - Roman V Rumyantsev
- G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Tropinina 49, 603950 Nizhny Novgorod, Russian Federation.
| | - Georgy K Fukin
- G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Tropinina 49, 603950 Nizhny Novgorod, Russian Federation.
| | - Mikhail N Bochkarev
- G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Tropinina 49, 603950 Nizhny Novgorod, Russian Federation.
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23
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Xie P, Xue C, Du D, Shi S. Photo-induced oxidative cleavage of C-C double bonds for the synthesis of biaryl methanone via CeCl 3 catalysis. Org Biomol Chem 2021; 19:6781-6785. [PMID: 34312650 DOI: 10.1039/d1ob01002f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A Ce-catalyzed strategy is developed to produce biaryl methanones via photooxidative cleavage of C-C double bonds at room temperature. This reaction is performed under air and demonstrates high activity as well as functional group tolerance. A synergistic Ce/ROH catalytic mechanism is also proposed based on the experimental observations. This protocol should be the first successful Ce-catalyzed photooxidation reaction of olefins with air as the oxidant, which would provide inspiration for the development of novel Ce-catalyzed photochemical synthesis processes.
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Affiliation(s)
- Pan Xie
- College of Chemistry and Chemistry Engineering, Shaanxi Key Laboratory of Chemistry Additives for Industry, Shaanxi University of Science & Technology, Xi'an 710021, China.
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24
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KALITA PANKAJ, GOURA JOYDEB, NAYAK PRAKASH, COLACIO ENRIQUE, CHANDRASEKHAR VADAPALLI. Octanuclear {Ln8} complexes: magneto-caloric effect in the {Gd8} analogue. J CHEM SCI 2021. [DOI: 10.1007/s12039-021-01920-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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25
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Poe TN, Beltrán-Leiva MJ, Celis-Barros C, Nelson WL, Sperling JM, Baumbach RE, Ramanantoanina H, Speldrich M, Albrecht-Schönzart TE. Understanding the Stabilization and Tunability of Divalent Europium 2.2.2B Cryptates. Inorg Chem 2021; 60:7815-7826. [PMID: 33990139 DOI: 10.1021/acs.inorgchem.1c00300] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Lanthanides such as europium with more accessible divalent states are useful for studying redox stability afforded by macrocyclic organic ligands. Substituted cryptands, such as 2.2.2B cryptand, that increase the oxidative stability of divalent europium also provide coordination environments that support synthetic alterations of Eu(II) cryptate complexes. Two single crystal structures were obtained containing nine-coordinate Eu(II) 2.2.2B cryptate complexes that differ by a single coordination site, the occupation of which is dictated by changes in reaction conditions. A crystal structure containing a [Eu(2.2.2B)Cl]+ complex is obtained from a methanol-THF solvent mixture, while a methanol-acetonitrile solvent mixture affords a [Eu(2.2.2B)(CH3OH)]2+ complex. While both crystals exhibit the typical blue emission observed in most Eu(II) containing compounds as a result of 4f65d1 to 4f7 transitions, computational results show that the substitution of a Cl- anion in the place of a methanol molecule causes mixing of the 5d excited states in the Eu(II) 2.2.2B cryptate complex. Additionally, magnetism studies reveal the identity of the capping ligand in the Eu(II) 2.2.2B cryptate complex may also lead to exchange between Eu(II) metal centers facilitated by π-stacking interactions within the structure, slightly altering the anticipated magnetic moment. The synthetic control present in these systems makes them interesting candidates for studying less stable divalent lanthanides and the effects of precise modifications of the electronic structures of low valent lanthanide elements.
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Affiliation(s)
- Todd N Poe
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee 32306, Florida, United States
| | - Maria J Beltrán-Leiva
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee 32306, Florida, United States
| | - Cristian Celis-Barros
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee 32306, Florida, United States
| | - William L Nelson
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Joseph M Sperling
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee 32306, Florida, United States
| | - Ryan E Baumbach
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Harry Ramanantoanina
- Department of Chemistry, Johannes Gutenberg-University of Mainz, Staudingerweg 18, 55128 Mainz, Germany
| | - Manfred Speldrich
- Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Thomas E Albrecht-Schönzart
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee 32306, Florida, United States.,National High Magnetic Field Laboratory, 1800 E. Paul Dirac Drive, Tallahassee, Florida 32310, United States
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26
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Gao Y, Chen N, Tian Y, Zhang J, Jia D. Polymeric Iodoargentate Hybrids Incorporating Octakis- or Heptakis-Solvated Lanthanide Complexes: Syntheses, Crystal Structures, and Photocatalysis. Inorg Chem 2021; 60:3761-3772. [DOI: 10.1021/acs.inorgchem.0c03528] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Yan Gao
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People’s Republic of China
| | - Niannian Chen
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People’s Republic of China
| | - Yiming Tian
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People’s Republic of China
| | - Jiahua Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People’s Republic of China
| | - Dingxian Jia
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People’s Republic of China
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27
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Hay MA, Boskovic C. Lanthanoid Complexes as Molecular Materials: The Redox Approach. Chemistry 2021; 27:3608-3637. [PMID: 32965741 DOI: 10.1002/chem.202003761] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Indexed: 11/05/2022]
Abstract
The development of molecular materials with novel functionality offers promise for technological innovation. Switchable molecules that incorporate redox-active components are enticing candidate compounds due to their potential for electronic manipulation. Lanthanoid metals are most prevalent in their trivalent state and usually redox-activity in lanthanoid complexes is restricted to the ligand. The unique electronic and physical properties of lanthanoid ions have been exploited for various applications, including in magnetic and luminescent materials as well as in catalysis. Lanthanoid complexes are also promising for applications reliant on switchability, where the physical properties can be modulated by varying the oxidation state of a coordinated ligand. Lanthanoid-based redox activity is also possible, encompassing both divalent and tetravalent metal oxidation states. Thus, utilization of redox-active lanthanoid metals offers an attractive opportunity to further expand the capabilities of molecular materials. This review surveys both ligand and lanthanoid centered redox-activity in pre-existing molecular systems, including tuning of lanthanoid magnetic and photophysical properties by modulating the redox states of coordinated ligands. Ultimately the combination of redox-activity at both ligands and metal centers in the same molecule can afford novel electronic structures and physical properties, including multiconfigurational electronic states and valence tautomerism. Further targeted exploration of these features is clearly warranted, both to enhance understanding of the underlying fundamental chemistry, and for the generation of a potentially important new class of molecular material.
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Affiliation(s)
- Moya A Hay
- School of Chemistry, University of Melbourne, Victoria, 3010, Australia
| | - Colette Boskovic
- School of Chemistry, University of Melbourne, Victoria, 3010, Australia
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28
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Bailey MD, Jin GX, Carniato F, Botta M, Allen MJ. Rational Design of High-Relaxivity Eu II -Based Contrast Agents for Magnetic Resonance Imaging of Low-Oxygen Environments. Chemistry 2021; 27:3114-3118. [PMID: 33226696 PMCID: PMC7902434 DOI: 10.1002/chem.202004450] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 11/21/2020] [Indexed: 01/01/2023]
Abstract
Metal-based contrast agents for magnetic resonance imaging present a promising avenue to image hypoxia. EuII -based contrast agents have a unique biologically relevant redox couple, EuII/III , that distinguishes this metal for use in hypoxia imaging. To that end, we investigated a strategy to enhance the contrast-enhancing capabilities of EuII -based cryptates in magnetic resonance imaging by controlling the rotational dynamics. Two dimetallic, EuII -containing cryptates were synthesized to test the efficacy of rigid versus flexible coupling strategies. A flexible strategy to dimerization led to a modest (114 %) increase in contrast enhancement per Eu ion (60 MHz, 298 K), but a rigid linking strategy led to an excellent (186 %) increase in contrast enhancement despite this compound's having the smaller molecular mass of the two dimetallic complexes. We envision the rigid linking strategy to be useful in the future design of potent EuII -based contrast agents for magnetic resonance imaging.
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Affiliation(s)
- Matthew D Bailey
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI, 48202, USA
| | - Guo-Xia Jin
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for, Chemical Imaging, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Jinan, 250014, P. R. China
| | - Fabio Carniato
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale "Amedeo Avogadro", Viale T. Michel 11, 15121, Alessandria, Italy
| | - Mauro Botta
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale "Amedeo Avogadro", Viale T. Michel 11, 15121, Alessandria, Italy
| | - Matthew J Allen
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI, 48202, USA
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29
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Highly efficient and air-stable Eu(II)-containing azacryptates ready for organic light-emitting diodes. Nat Commun 2020; 11:5218. [PMID: 33060573 PMCID: PMC7562750 DOI: 10.1038/s41467-020-19027-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 09/24/2020] [Indexed: 02/02/2023] Open
Abstract
Divalent europium 5d-4f transition has aroused great attention in many fields, in a way of doping Eu2+ ions into inorganic solids. However, molecular Eu2+ complexes with 5d-4f transition are thought to be too air-unstable to explore their applications. In this work, we synthesized four Eu2+-containing azacryptates EuX2-Nn (X = Br, I, n = 4, 8) and systematically studied the photophysical properties in crystalline samples and solutions. Intriguingly, the EuX2-N8 complexes exhibit near-unity photoluminescence quantum yield, good air-/thermal-stability and mechanochromic property (X = I). Furthermore, we proved the application of Eu2+ complexes in organic light-emitting diodes (OLEDs) with high efficiency and luminance. The optimized device employing EuI2-N8 as emitter has the best performance as the maximum luminance, current efficiency, and external quantum efficiency up to 25470 cd m−2, 62.4 cd A−1, and 17.7%, respectively. Our work deepens the understanding of structure-property relationship in molecular Eu2+ complexes and could inspire further research on application in OLEDs. Though divalent-europium-based complexes are promising materials for next-generation light-emitting devices, their poor air stability limits their applicability. Here, the authors report the design of air stable divalent-europium-based complexes for efficient organic light-emitting diodes.
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30
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Huh DN, Ciccone SR, Bekoe S, Roy S, Ziller JW, Furche F, Evans WJ. Synthesis of Ln II -in-Cryptand Complexes by Chemical Reduction of Ln III -in-Cryptand Precursors: Isolation of a Nd II -in-Cryptand Complex. Angew Chem Int Ed Engl 2020; 59:16141-16146. [PMID: 32441487 DOI: 10.1002/anie.202006393] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Indexed: 01/15/2023]
Abstract
Lanthanide triflates have been used to incorporate NdIII and SmIII ions into the 2.2.2-cryptand ligand (crypt) to explore their reductive chemistry. The Ln(OTf)3 complexes (Ln=Nd, Sm; OTf=SO3 CF3 ) react with crypt in THF to form the THF-soluble complexes [LnIII (crypt)(OTf)2 ][OTf] with two triflates bound to the metal encapsulated in the crypt. Reduction of these LnIII -in-crypt complexes using KC8 in THF forms the neutral LnII -in-crypt triflate complexes [LnII (crypt)(OTf)2 ]. DFT calculations on [NdII (crypt)]2+ ], the first NdII cryptand complex, assign a 4f4 electron configuration to this ion.
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Affiliation(s)
- Daniel N Huh
- Department of Chemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Sierra R Ciccone
- Department of Chemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Samuel Bekoe
- Department of Chemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Saswata Roy
- Department of Chemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Joseph W Ziller
- Department of Chemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Filipp Furche
- Department of Chemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - William J Evans
- Department of Chemistry, University of California, Irvine, Irvine, CA, 92697, USA
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31
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Barraza R, Allen MJ. Lanthanide Luminescence in Visible-Light-Promoted Photochemical Reactions. Molecules 2020; 25:molecules25173892. [PMID: 32858962 PMCID: PMC7503482 DOI: 10.3390/molecules25173892] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 11/17/2022] Open
Abstract
The excitation of lanthanides with visible light to promote photochemical reactions has garnered interest in recent years. Lanthanides serve as initiators for photochemical reactions because they exhibit visible-light-promoted 4f→5d transitions that lead to emissive states with electrochemical potentials that are more negative than the corresponding ground states. The lanthanides that have shown the most promising characteristics for visible-light promoted photoredox are SmII, EuII, and CeIII. By understanding the effects that ligands have on the 5d orbitals of SmII, EuII, and CeIII, luminescence and reactivity can be rationally modulated using coordination chemistry. This review briefly overviews the photochemical reactivity of SmII, EuII, and CeIII with visible light; the properties that influence the reactivity of these ions; and the research that has been reported towards modulating their photochemical-relevant properties using visible light and coordination chemistry.
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32
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Basal LA, Kajjam AB, Bailey MD, Allen MJ. Systematic Tuning of the Optical Properties of Discrete Complexes of Eu II in Solution Using Counterions and Solvents. Inorg Chem 2020; 59:9476-9480. [PMID: 32618468 DOI: 10.1021/acs.inorgchem.0c01516] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We describe a systematic study of the influence of halides and solvents on the optical properties of EuII-containing complexes in solution starting from well-defined crystalline precursors. Anionic halides, chloride and bromide, blue-shift the spectroscopic properties of EuII, whereas neutral ligands, methanol and acetonitrile, cause a red shift. This system provides evidence that EuII has a stronger affinity for chloride, and to some extent bromide, relative to acetonitrile but not methanol. We also describe a simple procedure using an ion-exchange resin for the exchange of iodide counterions to hexafluorophosphate. These findings are a step toward designing ligands that can tune the optical properties of EuII-containing complexes for solution-based applications.
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Affiliation(s)
- Lina A Basal
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States.,Department of Chemistry and Biochemistry, Colorado College, 1040 North Nevada Avenue, Colorado Springs, Colorado 80903, United States
| | - Aravind B Kajjam
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Matthew D Bailey
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Matthew J Allen
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
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33
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Yu D, To WP, Tong GSM, Wu LL, Chan KT, Du L, Phillips DL, Liu Y, Che CM. Luminescent tungsten(vi) complexes as photocatalysts for light-driven C-C and C-B bond formation reactions. Chem Sci 2020; 11:6370-6382. [PMID: 32874518 PMCID: PMC7448528 DOI: 10.1039/d0sc01340d] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/23/2020] [Indexed: 12/13/2022] Open
Abstract
The realization of photocatalysis for practical synthetic application hinges on the development of inexpensive photocatalysts which can be prepared on a large scale. Herein an air-stable, visible-light-absorbing photoluminescent tungsten(vi) complex which can be conveniently prepared at the gram-scale is described. This complex could catalyse photochemical organic transformation reactions including borylation of aryl halides, such as aryl chloride, reductive coupling of benzyl bromides for C-C bond formation, reductive coupling of phenacyl bromides, and decarboxylative coupling of redox-active esters of alkyl carboxylic acid with high product yields and broad functional group tolerance.
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Affiliation(s)
- Daohong Yu
- Department of Chemistry , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China .
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Wai-Pong To
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Glenna So Ming Tong
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Liang-Liang Wu
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Kaai-Tung Chan
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Lili Du
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - David Lee Phillips
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Yungen Liu
- Department of Chemistry , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China .
| | - Chi-Ming Che
- Department of Chemistry , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China .
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
- HKU Shenzhen Institute of Research and Innovation Shenzhen , Guangdong 518055 , China
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34
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Huh DN, Ciccone SR, Bekoe S, Roy S, Ziller JW, Furche F, Evans WJ. Synthesis of Ln
II
‐in‐Cryptand Complexes by Chemical Reduction of Ln
III
‐in‐Cryptand Precursors: Isolation of a Nd
II
‐in‐Cryptand Complex. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202006393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Daniel N. Huh
- Department of Chemistry University of California, Irvine Irvine CA 92697 USA
| | - Sierra R. Ciccone
- Department of Chemistry University of California, Irvine Irvine CA 92697 USA
| | - Samuel Bekoe
- Department of Chemistry University of California, Irvine Irvine CA 92697 USA
| | - Saswata Roy
- Department of Chemistry University of California, Irvine Irvine CA 92697 USA
| | - Joseph W. Ziller
- Department of Chemistry University of California, Irvine Irvine CA 92697 USA
| | - Filipp Furche
- Department of Chemistry University of California, Irvine Irvine CA 92697 USA
| | - William J. Evans
- Department of Chemistry University of California, Irvine Irvine CA 92697 USA
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35
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Mondal A, Mukhopadhyay C. Construction of Carbon-Carbon and Carbon-Heteroatom Bonds: Enabled by Visible Light. CURR ORG CHEM 2020. [DOI: 10.2174/1385272824666200211115154] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present review provides an overview of visible light-mediated environment-
friendly approaches over the past decade for the formation of carbon-carbon and
carbon-heteroatom framework. This area has recently emerged as a versatile, environmentally
benign and green platform for the development of a highly sustainable synthetic
methodology. According to the recent advancements, visible light has come to the forefront
in synthetic organic chemistry as a powerful green strategy for the activation of small
molecules.
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Affiliation(s)
- Animesh Mondal
- Department of Chemistry, University of Calcutta, 92 APC Road, Kolkata-700009, India
| | - Chhanda Mukhopadhyay
- Department of Chemistry, University of Calcutta, 92 APC Road, Kolkata-700009, India
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36
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Ma J, Schäfers F, Daniliuc C, Bergander K, Strassert CA, Glorius F. Gadolinium Photocatalysis: Dearomative [2+2] Cycloaddition/Ring‐Expansion Sequence with Indoles. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202001200] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Jiajia Ma
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität Münster Corrensstrasse 40 48149 Münster Germany
| | - Felix Schäfers
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität Münster Corrensstrasse 40 48149 Münster Germany
| | - Constantin Daniliuc
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität Münster Corrensstrasse 40 48149 Münster Germany
| | - Klaus Bergander
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität Münster Corrensstrasse 40 48149 Münster Germany
| | - Cristian A. Strassert
- CeNTech, CiMIC, SoN, Institut für Anorganische und Analytische ChemieWestfälische Wilhelms-Universität Münster Heisenbergstraße 11 48149 Münster Germany
| | - Frank Glorius
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität Münster Corrensstrasse 40 48149 Münster Germany
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37
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Ma J, Schäfers F, Daniliuc C, Bergander K, Strassert CA, Glorius F. Gadolinium Photocatalysis: Dearomative [2+2] Cycloaddition/Ring‐Expansion Sequence with Indoles. Angew Chem Int Ed Engl 2020; 59:9639-9645. [DOI: 10.1002/anie.202001200] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Indexed: 02/06/2023]
Affiliation(s)
- Jiajia Ma
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität Münster Corrensstrasse 40 48149 Münster Germany
| | - Felix Schäfers
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität Münster Corrensstrasse 40 48149 Münster Germany
| | - Constantin Daniliuc
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität Münster Corrensstrasse 40 48149 Münster Germany
| | - Klaus Bergander
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität Münster Corrensstrasse 40 48149 Münster Germany
| | - Cristian A. Strassert
- CeNTech, CiMIC, SoN, Institut für Anorganische und Analytische ChemieWestfälische Wilhelms-Universität Münster Heisenbergstraße 11 48149 Münster Germany
| | - Frank Glorius
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität Münster Corrensstrasse 40 48149 Münster Germany
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38
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Jenks TC, Kuda-Wedagedara ANW, Bailey MD, Ward CL, Allen MJ. Spectroscopic and Electrochemical Trends in Divalent Lanthanides through Modulation of Coordination Environment. Inorg Chem 2020; 59:2613-2620. [PMID: 31999439 DOI: 10.1021/acs.inorgchem.0c00136] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Due to the importance of both visible-light luminescence and lanthanides in modern society, the influence of the ligand environment on complexes of YbII were studied and compared with analogous complexes of EuII. Four ligands with systematically varied electronic and steric characteristics were used to probe the coordination environment and electronic and redox properties of the corresponding YbII-containing complexes. Strong-field nitrogenous donors gave rise to bathochromic shifts, leading to visible-light absorption by YbII. Trends in properties across the series of YbII-containing complexes were compared to trends reported for the analogous EuII-containing complexes, revealing the translatability of coordination environment effects across the divalent lanthanide series. These studies provide valuable information regarding the behavior of small and medium-sized divalent lanthanides outside of the solid state.
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39
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Lenora CU, Staples RJ, Allen MJ. Measurement of the Dissociation of Eu II-Containing Cryptates Using Murexide. Inorg Chem 2020; 59:86-93. [PMID: 30777754 DOI: 10.1021/acs.inorgchem.8b03605] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The dissociation rates of five EuII-containing cryptates in water were measured using UV-visible spectroscopy and murexide at pH 6.5, 7, 7.5, 8, and 9. Murexide was used as a coordinating dye for EuII. The results for a known cryptate were within experimental error of the value obtained using other methods and enabled the measurement of other cryptates. This validation of the use of murexide to study the dissociation of EuII-containing cryptates enables its use with other complexes of EuII.
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Affiliation(s)
- Chamika U Lenora
- Department of Chemistry , Wayne State University , Detroit , Michigan 48202 , United States
| | - Richard J Staples
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Matthew J Allen
- Department of Chemistry , Wayne State University , Detroit , Michigan 48202 , United States
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40
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Qi H, Zhao Z, Zhan G, Sun B, Yan W, Wang C, Wang L, Liu Z, Bian Z, Huang C. Air stable and efficient rare earth Eu( ii) hydro-tris(pyrazolyl)borate complexes with tunable emission colors. Inorg Chem Front 2020. [DOI: 10.1039/d0qi00762e] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Eu(ii) complexes with high air stability and tunable emission colors were synthesized and characterized.
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41
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Kerzig C, Wenger OS. Reactivity control of a photocatalytic system by changing the light intensity. Chem Sci 2019; 10:11023-11029. [PMID: 32206254 PMCID: PMC7069242 DOI: 10.1039/c9sc04584h] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 10/08/2019] [Indexed: 12/13/2022] Open
Abstract
By using simple optics such as a lens, switching between one- and two-photon driven reaction mechanisms became feasible, which allows the control over the main products of photochemical reactions.
We report a novel light-intensity dependent reactivity approach allowing us to selectively switch between triplet energy transfer and electron transfer reactions, or to regulate the redox potential available for challenging reductions. Simply by adjusting the light power density with an inexpensive lens while keeping all other parameters constant, we achieved control over one- and two-photon mechanisms, and successfully exploited our approach for lab-scale photoreactions using three substrate classes with excellent selectivities and good product yields. Specifically, our proof-of-concept study demonstrates that the irradiation intensity can be used to control (i) the available photoredox reactivity for reductive dehalogenations to selectively target either bromo- or chloro-substituted arenes, (ii) the photochemical cis–trans isomerization of olefins versus their photoreduction, and (iii) the competition between hydrogen atom abstraction and radical dimerization processes.
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Affiliation(s)
- Christoph Kerzig
- Department of Chemistry , University of Basel , St. Johanns-Ring 19 , 4056 Basel , Switzerland . ;
| | - Oliver S Wenger
- Department of Chemistry , University of Basel , St. Johanns-Ring 19 , 4056 Basel , Switzerland . ;
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42
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Nimkar A, Maity S, Flowers RA, Hoz S. Contrasting Effect of Additives on Photoinduced Reactions of SmI 2. Chemistry 2019; 25:10499-10504. [PMID: 31150561 DOI: 10.1002/chem.201901997] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 05/30/2019] [Indexed: 11/07/2022]
Abstract
The work described herein compares the effect of additives (HMPA, methanol, ethylene glycol, pinacol, N-methylethanolamine) on thermal and photochemical reactions of samarium diiodide (SmI2 ). In thermal reactions, additives that coordinate to SmI2 induce a significant increase in reaction rate. In photochemical reactions, the presence of an electronegative atom with a highly localized negative charge on the substrate leads to a rate deceleration. In order to benefit from the columbic interaction with the positively charged samarium cation, these substrates react preferentially by an inner sphere reduction mechanism. The addition of ligands prevents this close interaction causing rate retardation. Furthermore, studies demonstrate that excited state quenching of SmII by ethylene glycol and other additives indicate that it is unlikely to be the major cause for the observed rate retardation. This effect provides a simple diagnostic tool to distinguish between an inner and an outer sphere reduction mechanism.
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Affiliation(s)
- Amey Nimkar
- Department of Chemistry, Bar-Ilan University, Ramat Gan, 5290002, Israel
| | - Sandeepan Maity
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania, 18015, USA
| | - Robert A Flowers
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania, 18015, USA
| | - Shmaryahu Hoz
- Department of Chemistry, Bar-Ilan University, Ramat Gan, 5290002, Israel
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43
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Huh DN, Ziller JW, Evans WJ. Facile Encapsulation of Ln(II) Ions into Cryptate Complexes from LnI 2(THF) 2 Precursors (Ln = Sm, Eu, Yb). Inorg Chem 2019; 58:9613-9617. [PMID: 31290306 DOI: 10.1021/acs.inorgchem.9b01049] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reactivity of LnI2(THF)2 (Ln = Sm, Eu, Yb; THF = tetrahydrofuran) with 2.2.2-cryptand (crypt) was explored to see if these readily accessible precursors could provide new examples of lanthanide-in-crypt complexes. The crystallographically characterized Ln(II)-in-crypt complexes [Ln(crypt)(DMF)2][I]2 (Ln = Sm, Eu) and [Yb(crypt)(DMF)][I]2 (DMF = dimethylformamide) were synthesized by reacting LnI2(THF)2 (Ln = Sm, Eu, Yb) with crypt in THF and recrystallizing from DMF. Crystallographic data were also obtained on the Ln(II)-in-crypt (Ln = Sm, Eu) complexes [Ln(crypt)(DMF)2][BPh4]2, which were synthesized by addition of 2 equiv of NaBPh4 to [Ln(crypt)(DMF)2][I]2.
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Affiliation(s)
- Daniel N Huh
- Department of Chemistry , University of California , Irvine , California 92697 , United States
| | - Joseph W Ziller
- Department of Chemistry , University of California , Irvine , California 92697 , United States
| | - William J Evans
- Department of Chemistry , University of California , Irvine , California 92697 , United States
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44
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Gan H. Facile Preparation of Benzoxazoles from S
8
‐Promoted Cyclization of 2‐Nitrophenols with Arylmethyl Chloride. ChemistrySelect 2019. [DOI: 10.1002/slct.201900550] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Haifeng Gan
- College of Biotechnology and Pharmaceutical EngineeringNanjing Tech University Nanjing Jiangsu 211800 P. R. China
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45
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Abstract
The rare earths (REs) are a family of 17 elements that exhibit pronounced chemical similarities as a group, while individually expressing distinctive and varied electronic properties. These atomistic electronic properties are extraordinarily useful and motivate the application of REs in many technologies and devices. From their discovery to the present day, a major challenge faced by chemists has been the separation of RE elements, which has evolved from tedious crystallization to highly engineered solvent extraction schemes. The increasing incorporation and dependence of REs in technology have raised concerns about their sustainability and motivated recent studies for improved separations to achieve a circular RE economy.
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Kim S, Kim Y, Jin H, Park MH, Kim Y, Lee KM, Kim M. Europium‐Catalyzed Aerobic Oxidation of Alcohols to Aldehydes/Ketones and Photoluminescence Tracking. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201801499] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Seongwoo Kim
- Department of Chemistry and BK21Plus Program Research TeamChungbuk National University, Cheongju Chungbuk 28644 South Korea
| | - Youngik Kim
- Department of Chemistry and BK21Plus Program Research TeamChungbuk National University, Cheongju Chungbuk 28644 South Korea
| | - Hyomin Jin
- Department of Chemistry, Institute of Molecular Science and Fusion TechnologyKangwon National University, Chuncheon Gangwon 24341 South Korea
| | - Myung Hwan Park
- Department of Chemistry EducationChungbuk National University, Cheongju Chungbuk 28644 South Korea
| | - Youngjo Kim
- Department of Chemistry and BK21Plus Program Research TeamChungbuk National University, Cheongju Chungbuk 28644 South Korea
| | - Kang Mun Lee
- Department of Chemistry, Institute of Molecular Science and Fusion TechnologyKangwon National University, Chuncheon Gangwon 24341 South Korea
| | - Min Kim
- Department of Chemistry and BK21Plus Program Research TeamChungbuk National University, Cheongju Chungbuk 28644 South Korea
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Maity S, Flowers RA. Mechanistic Study and Development of Catalytic Reactions of Sm(II). J Am Chem Soc 2019; 141:3207-3216. [DOI: 10.1021/jacs.8b13119] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Sandeepan Maity
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Robert A. Flowers
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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48
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Qiao Y, Cheisson T, Manor BC, Carroll PJ, Schelter EJ. A strategy to improve the performance of cerium(iii) photocatalysts. Chem Commun (Camb) 2019; 55:4067-4070. [DOI: 10.1039/c9cc00282k] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A structural modification strategy to improve the photocatalytic performance of molecular cerium(iii) luminophores was demonstrated.
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Affiliation(s)
- Yusen Qiao
- P. Roy and Diana T. Vagelos Laboratories
- Department of Chemistry
- University of Pennsylvania
- Philadelphia
- USA
| | - Thibault Cheisson
- P. Roy and Diana T. Vagelos Laboratories
- Department of Chemistry
- University of Pennsylvania
- Philadelphia
- USA
| | - Brian C. Manor
- P. Roy and Diana T. Vagelos Laboratories
- Department of Chemistry
- University of Pennsylvania
- Philadelphia
- USA
| | - Patrick J. Carroll
- P. Roy and Diana T. Vagelos Laboratories
- Department of Chemistry
- University of Pennsylvania
- Philadelphia
- USA
| | - Eric J. Schelter
- P. Roy and Diana T. Vagelos Laboratories
- Department of Chemistry
- University of Pennsylvania
- Philadelphia
- USA
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49
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Abstract
The use of earth-abundant, cheap, potent, and readily available lanthanide photocatalysts provides an opportunity to complement or even replace rare and precious metal photosensitizers. Moreover, lanthanide photosensitizers have been demonstrated for the generation of a variety of reactive species, including aryl radicals, alkyl radicals, and others, by single-electron-transfer (SET) and hydrogen atom transfer (HAT) pathways under mild reaction conditions. Some lanthanide photocatalysts have unprecedented reducing power from their photoexcited states, achieving the activation of challenging organic substrates that have not otherwise been activated by reported organic or transition-metal photosensitizers. In this Account, we describe our recent advances in the rational design and strategic application of lanthanide photo(redox)catalysis. Our research goals include understanding the photophysics of lanthanide luminophores and incorporating them into new photocatalysis. Among the lanthanides, we have focused on cerium because of the doublet to doublet 4f → 5d excitation and emission, which affords good conservation of energy without losses through spin-state changes, as well as a large natural abundance of that element. We have performed structural, spectroscopic, computational, and reactivity studies to demonstrate that luminescent Ce(III) guanidinate-amide complexes can mediate photocatalytic C(sp3)-C(sp3) bond forming reactions. Taking advantage of the strong reducing power of the cerium excited states and the cerium-halogen bond forming enthalpies, we determined that the reactive, excited-state cerium metalloradical abstracts chloride anion from benzyl chloride to generate the benzyl radical. To control and predict the photocatalytic reactivities, we have also performed photophysical and photochemical studies on a series of mixed-ligand Ce(III) guanidinate-amide and guanidinate-aryloxide complexes to establish structure-property relationship for Ce(III) photocatalysts. We discovered that the emission color is directly related to ligand type and rigidity of the coordination sphere and that the photoluminescent quantum yield is correlated to variation in steric encumbrance around the cerium centers. The low excited-state reduction potentials ( E1/2* ≈ -2.1 to -2.9 V versus Cp2Fe0/+) and relatively fast quenching rates ( kq ≈ 107 M-1 s-1) toward aryl halides enabled the Ce(III) guanidinate-amide complexes to participate in photocatalytic C(sp2)-C(sp2) bond forming reactions through either inner-sphere or outer-sphere SET processes. We have also reported a simple, potent, and air-stable ultraviolet A photoreductant, the hexachlorocerate(III) anion ([CeIIICl6]3-). This complex is a potent photoreductant ( E1/2* ≈ -3.45 V versus Cp2Fe0/+) and exhibits a fast quenching kinetics ( kq ≈ 109-1010 M-1 s-1) toward organohalogens. The [CeIVCl6]2- redox partner can also act as a potent photo-oxidant though a (presumably) long-lived chloride-to-cerium(IV) charge transfer excited state (ε = ∼6000 M-1 cm-1), that was used to turnover photocatalytic dechlorination and Miyuara borylation reactions. With [CeIIICl6]3-, we achieved efficient photoinduced dehalogenation and borylation of unactivated aryl chlorides with broad substrate scope, through formally two-photon cycles where both Ce(III) and Ce(IV) act as photocatalysts. Lanthanide photoredox catalysis is now being applied in several contexts for reactions including photocatalytic dehydrogenation of amines, alkoxy-radical-mediated C-C bond cleavage and amination of alkanols, and C-H activation of alkanes. Overall, simple and potent lanthanide photocatalysis is expected to find practical applications in organic synthesis, pharmaceutical development, and small molecule activation.
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Affiliation(s)
- Yusen Qiao
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 S. 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Eric J. Schelter
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 S. 34th Street, Philadelphia, Pennsylvania 19104, United States
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50
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Corbin BA, Basal LA, White SA, Shen Y, Haacke EM, Fishbein KW, Allen MJ. Screening of ligands for redox-active europium using magnetic resonance imaging. Bioorg Med Chem 2018; 26:5274-5279. [PMID: 29653832 DOI: 10.1016/j.bmc.2018.04.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/27/2018] [Accepted: 04/01/2018] [Indexed: 12/31/2022]
Abstract
We report a screening procedure to predict ligand coordination to EuII and EuIII using magnetic resonance imaging in which bright images indicate complexation and dark images indicate no complexation. Here, paramagnetic GdIII is used as a surrogate for EuIII in the screening procedure to enable detection with magnetic resonance imaging. The screening procedure was tested using a set of eight ligands with known coordination to EuII and EuIII, and results were found to be consistent with expected binding. Validation of the screening procedure with known coordination chemistry enables use with new ligands in the future.
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Affiliation(s)
- Brooke A Corbin
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, United States
| | - Lina A Basal
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, United States
| | - Susan A White
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, United States
| | - Yimin Shen
- Department of Radiology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - E Mark Haacke
- Department of Radiology, Wayne State University School of Medicine, Detroit, MI 48201, United States; Barbara Ann Karmanos Cancer Institute, Detroit, MI 48201, United States
| | - Kenneth W Fishbein
- National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States
| | - Matthew J Allen
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, United States; Barbara Ann Karmanos Cancer Institute, Detroit, MI 48201, United States.
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