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Kracht F, Rolser P, Preisenberger P, Maichle‐Mössmer C, Anwander R. Organomagnesia: Reversibly High Carbon Dioxide Uptake by Magnesium Pyrazolates. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2403295. [PMID: 39189457 PMCID: PMC11348227 DOI: 10.1002/advs.202403295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/31/2024] [Indexed: 08/28/2024]
Abstract
A series of new pyrazolate and mixed pyrazolate/pyrazole magnesium complexes is described and their reactivity toward carbon dioxide is examined. The dimeric complex [Mg(pzt Bu, t Bu)2]2 inserts CO2 instantly and quantitatively forming the tetrameric complex [Mg(CO2·pzt Bu, t Bu)2]4 and monomeric donor-stabilized [Mg(CO2·pzt Bu, t Bu)2(thf)2]. Complexes of the type [Mgx(pzR,R)2 x(HpzR,R)y]n (R = iPr, tBu) engage in similar insertion reactions involving dissociation of the carbamic acid HOOCpzR,R. Even solid polymeric derivatives [Mg(pzR,R)2]n (R = Me, H) react instantaneously and exhaustively with CO2, the resulting [Mg(CO2·pz)2]m featuring a CO2 capacity of 35.7 wt% (8.2 mmol g-1). All described magnesium pyrazolates display completely reversible CO2 uptake in solution and in the solid state, respectively, as monitored via VT 1H NMR and in situ FTIR spectroscopy as well as thermogravimetric analysis. Fluorinated [Mg2(pzCF3,CF3)4(thf)3] does not yield any isolable CO2 insertion product but exhibits the highest activity in the catalytic transformation of epoxides and CO2 to cyclic carbonates.
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Affiliation(s)
- Felix Kracht
- Institut für Anorganische ChemieEberhard Karls Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - Philipp Rolser
- Institut für Anorganische ChemieEberhard Karls Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - Paul Preisenberger
- Institut für Anorganische ChemieEberhard Karls Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - Cäcilia Maichle‐Mössmer
- Institut für Anorganische ChemieEberhard Karls Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - Reiner Anwander
- Institut für Anorganische ChemieEberhard Karls Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
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Hirneise L, Buschmann DA, Maichle-Mössmer C, Anwander R. Cerium Fluorenyl Complexes Including CC Coupling Reactions. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lars Hirneise
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Dennis A. Buschmann
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Cäcilia Maichle-Mössmer
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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Abstract
The number of rare earth (RE) starting materials used in synthesis is staggering, ranging from simple binary metal-halide salts to borohydrides and "designer reagents" such as alkyl and organoaluminate complexes. This review collates the most important starting materials used in RE synthetic chemistry, including essential information on their preparations and uses in modern synthetic methodologies. The review is divided by starting material category and supporting ligands (i.e., metals as synthetic precursors, halides, borohydrides, nitrogen donors, oxygen donors, triflates, and organometallic reagents), and in each section relevant synthetic methodologies and applications are discussed.
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Affiliation(s)
- Fabrizio Ortu
- School of Chemistry, University of Leicester, LE1 7RH Leicester, U.K.
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Guo Z, Blair VL, Deacon GB, Junk PC. Europium is Different: Solvent and Ligand Effects on Oxidation State Outcomes and C-F Activation in Reactions Between Europium Metal and Pentafluorophenylsilver. Chemistry 2021; 28:e202103865. [PMID: 34859510 DOI: 10.1002/chem.202103865] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Indexed: 01/10/2023]
Abstract
Unique outcomes have emerged from the redox transmetallation/ protolysis (RTP) reactions of europium metal with [Ag(C6 F5 )(py)] (py=pyridine) and pyrazoles (RR'pzH). In pyridine, a solvent not normally used for RTP reactions, the products were mainly EuII complexes, [Eu(RR'pz)2 (py)4 ] (RR'pz=3,5-diphenylpyrazolate (Ph2 pz) 1; 3-(2-thienyl)-5-trifluoromethylpyrazolate (ttfpz) 2; 3-methyl-5-phenylpyrazolate (PhMepz) 3). However, use of 3,5-di-tert-butylpyrazole (tBu2 pzH) gave trivalent [Eu(tBu2 pz)3 (py)2 ] 4, whereas the bulkier N,N'-bis(2,6-difluorophenyl)formamidine (DFFormH) gave divalent [Eu(DFForm)2 (py)3 ] 5. In tetrahydrofuran (thf), the usual solvent for RTP reactions, C-F activation was observed for the first time with [Ag(C6 F5 )(py)] in such reactions. Thus trivalent [{Eu2 (Ph2 pz)4 (py)4 (thf)2 (μ-F)2 }{Eu2 (Ph2 pz)4 (py)2 (thf)4 (μ-F)2 }] (6), [Eu2 (ttfpz)4 (py)2 (dme)2 (μ-F)2 ] (7), [Eu2 (tBu2 pz)4 (dme)2 (μ-F)2 ] (8) were obtained from the appropriate pyrazoles, the last two after crystallization from 1,2-dimethoxyethane (dme). Surprisingly 3,5-dimethylpyrazole (Me2 pzH) gave the divalent cage [Eu6 (Me2 pz)10 (thf)6 (μ-F)2 ] (9). This has a compact ovoid core held together by bridging fluoride, thf, and pyrazolate ligands, the last including the rare μ4 -1η5 (N2 C3 ): 2η2 (N,N'): 3κ(N): 4κ(N') pyrazolate binding mode. With the bulky N,N'-bis(2,6-diisopropylphenyl)formamidine (DippFormH), which often favours C-F activation in RTP reactions, neither oxidation to EuIII nor C-F activation was observed and [Eu(DippForm)2 (thf)2 ] (10) was isolated. By contrast, Eu reacted with Bi(C6 F5 )3 and Ph2 pzH or tBu2 pzH in thf without C-F activation, to give [Eu(Ph2 pz)2 (thf)4 ] (11) and [Eu(tBu2 pz)3 (thf)2 ] (12) respectively, the oxidation state outcomes corresponding to that for use of [Ag(C6 F5 )(py)] in pyridine.
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Affiliation(s)
- Zhifang Guo
- School of Chemistry, Monash University, Clayton, 3800, Australia.,College of Science & Engineering, James Cook University, Townsville, 4811, Qld, Australia
| | - Victoria L Blair
- School of Chemistry, Monash University, Clayton, 3800, Australia
| | - Glen B Deacon
- School of Chemistry, Monash University, Clayton, 3800, Australia
| | - Peter C Junk
- College of Science & Engineering, James Cook University, Townsville, 4811, Qld, Australia
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Werner D, Bayer U, Schädle D, Anwander R. Emergence of a New [NNN] Pincer Ligand via Si-H Bond Activation and β-Hydride Abstraction at Tetravalent Cerium. Chemistry 2020; 26:12194-12205. [PMID: 32239686 PMCID: PMC7540680 DOI: 10.1002/chem.202000625] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 03/19/2020] [Indexed: 01/08/2023]
Abstract
The cerium(IV) pyrazolate complexes [Ce(Me2 pz)4 ]2 and [Ce(Me2 pz)4 (thf)] initiate β-hydride abstraction of the bis(dimethylsilyl)amido moiety, to afford a heteroleptic cerium(IV) species containing a dimethylpyrazolyl-substituted silylamido ligand, namely [Ce(Me2 pz)3 (bpsa)] (bpsa=bis((3,5-dimethylpyrazol-1-yl)dimethylsilyl)amido; Me2 pz =3,5-dimethylpyrazolato), along with some cerium(III) species. Remarkably, the nucleophilic attack of the pyrazolyl at the silicon atom and concomitant Si-H-bond cleavage is restricted to the tetravalent cerium oxidation state and appears to proceed via the formation of a transient cerium(IV) hydride, which engages in immediate redox chemistry. When [Ce(Me2 pz)4 ]2 is treated with [Li{N(SiMe3 )2 }], that is, in the absence of the SiH functionality, any redox chemistry did not occur. Instead, the ceric ate complex [LiCe2 (Me2 pz)9 ] and the stable mixed-ligand ceric species [Ce(Me2 pz)2 {N(SiMe3 )2 }2 ] were obtained.
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Affiliation(s)
- Daniel Werner
- Institut für Anorganische ChemieUniversity of Tübingen (EKUT)Auf der Morgenstelle 1872076TübingenGermany
| | - Uwe Bayer
- Institut für Anorganische ChemieUniversity of Tübingen (EKUT)Auf der Morgenstelle 1872076TübingenGermany
| | - Dorothea Schädle
- Institut für Anorganische ChemieUniversity of Tübingen (EKUT)Auf der Morgenstelle 1872076TübingenGermany
| | - Reiner Anwander
- Institut für Anorganische ChemieUniversity of Tübingen (EKUT)Auf der Morgenstelle 1872076TübingenGermany
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Guo Z, Huo R, Tan YQ, Blair V, Deacon GB, Junk PC. Syntheses of reactive rare earth complexes by redox transmetallation/protolysis reactions–A simple and convenient method. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213232] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Bayer U, Werner D, Maichle‐Mössmer C, Anwander R. Effective and Reversible Carbon Dioxide Insertion into Cerium Pyrazolates. Angew Chem Int Ed Engl 2020; 59:5830-5836. [PMID: 31916355 PMCID: PMC7155069 DOI: 10.1002/anie.201916483] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Indexed: 12/18/2022]
Abstract
The homoleptic pyrazolate complexes [CeIII 4 (Me2 pz)12 ] and [CeIV (Me2 pz)4 ]2 quantitatively insert CO2 to give [CeIII 4 (Me2 pz⋅CO2 )12 ] and [CeIV (Me2 pz⋅CO2 )4 ], respectively (Me2 pz=3,5-dimethylpyrazolato). This process is reversible for both complexes, as observed by in situ IR and NMR spectroscopy in solution and by TGA in the solid state. By adjusting the molar ratio, one molecule of CO2 per [CeIV (Me2 pz)4 ] complex could be inserted to give trimetallic [Ce3 (Me2 pz)9 (Me2 pz⋅CO2 )3 (thf)]. Both the cerous and ceric insertion products catalyze the formation of cyclic carbonates from epoxides and CO2 under mild conditions. In the absence of epoxide, the ceric catalyst is prone to reduction by the co-catalyst tetra-n-butylammonium bromide (TBAB).
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Affiliation(s)
- Uwe Bayer
- Institut für Anorganische ChemieEberhard Karls Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - Daniel Werner
- Institut für Anorganische ChemieEberhard Karls Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - Cäcilia Maichle‐Mössmer
- Institut für Anorganische ChemieEberhard Karls Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - Reiner Anwander
- Institut für Anorganische ChemieEberhard Karls Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
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Bock L, Tran X, Liang Y, Kramer M, Maichle-Mössmer C, Anwander R. SOMC@Periodic Mesoporous Silica Nanoparticles: Meerwein–Ponndorf–Verley Reduction Promoted by Immobilized Rare-Earth-Metal Alkoxides. Organometallics 2020. [DOI: 10.1021/acs.organomet.9b00794] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Lorenz Bock
- Institut für Anorganische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Xuan Tran
- Institut für Anorganische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Yucang Liang
- Institut für Anorganische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Markus Kramer
- Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Cäcilia Maichle-Mössmer
- Institut für Anorganische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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Bayer U, Werner D, Maichle‐Mössmer C, Anwander R. Effective and Reversible Carbon Dioxide Insertion into Cerium Pyrazolates. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201916483] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Uwe Bayer
- Institut für Anorganische Chemie Eberhard Karls Universität Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
| | - Daniel Werner
- Institut für Anorganische Chemie Eberhard Karls Universität Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
| | - Cäcilia Maichle‐Mössmer
- Institut für Anorganische Chemie Eberhard Karls Universität Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie Eberhard Karls Universität Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
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Edelmann FT, Farnaby JH, Jaroschik F, Wilson B. Lanthanides and actinides: Annual survey of their organometallic chemistry covering the year 2018. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2019.07.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Rad NE, Junk PC, Deacon GB, Wang J. New Homoleptic Rare Earth 3,5‐Diphenylpyrazolates and 3,5‐Di‐
tert
‐butylpyrazolates and a Noteworthy Structural Discontinuity. Z Anorg Allg Chem 2019. [DOI: 10.1002/zaac.201900015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Nazli E. Rad
- College of Science & Engineering James Cook University 4811 Townsville QLD Australia
| | - Peter C. Junk
- College of Science & Engineering James Cook University 4811 Townsville QLD Australia
| | - Glen B. Deacon
- School of Chemistry Monash University 3800 Victoria Australia
| | - Jun Wang
- College of Science & Engineering James Cook University 4811 Townsville QLD Australia
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Guo Z, Blair V, Deacon GB, Junk PC. Can Bismuth Replace Mercury in Redox Transmetallation/Protolysis Syntheses from Free Lanthanoid Metals? Chemistry 2018; 24:17464-17474. [DOI: 10.1002/chem.201804703] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Zhifang Guo
- School of Chemistry; Monash University; Clayton 3800 Australia
| | - Victoria Blair
- School of Chemistry; Monash University; Clayton 3800 Australia
| | - Glen B. Deacon
- School of Chemistry; Monash University; Clayton 3800 Australia
| | - Peter C. Junk
- College of Science & Engineering; James Cook University; Townsville 4811 QLD Australia
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