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Schädle D, Litlabø R, Meermann-Zimmermann M, Thim-Spöring R, Schädle C, Maichle-Mössmer C, Törnroos KW, Anwander R. Rare-Earth-Metal Methyl and Methylidene Complexes Stabilized by Tp R,R'-Scorpionato Ligands─Size Matters. Inorg Chem 2024; 63:9624-9637. [PMID: 38407062 DOI: 10.1021/acs.inorgchem.3c04422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Homoleptic tetramethylaluminates Ln(AlMe4)3 react with KTptBu,Me (TptBu,Me = tris(3-tBu-5-Me-pyrazolyl)borato) to yield rare-earth-metal methylidene complexes (TptBu,Me)Ln(μ3-CH2)[(μ-Me)AlMe2]2 (Ln = La, Ce, Nd). The lanthanum reaction is prone to additional C-H- and B-N-bond activation, affording coproducts La[HB(pzMe,tBu)(pzCMe2,Me)2][(μ-CH2)(μ-Me)AlMe2]2 and [La(μ-pztBu,Me)(AlMe4)2]2 (pztBu,Me = 3-tBu-5-Me-pyrazolato). The protonolysis reaction of Ln(AlMe4)3 and HpztBu,Me provides more efficient access to [Ln(μ-pztBu,Me)(AlMe4)2]2 (Ln = La, Nd). Treatment of Ln(AlMe4)3 with KTpMe,Me led to methylidene complexes (TpMe,Me)Ln(μ3-CH2)[(μ-Me)AlMe2]2 (Ln = Nd, Sm) or bis(tetramethylaluminate) complexes (TpMe,Me)Ln(AlMe4)2 (Ln = Y, Lu). The neodymium reaction generated methine derivative (TpMe,Me)Nd[(μ4-CH)(AlMe2)2(μ-pz,Me,Me)][(μ-Me)AlMe2] as a minor coproduct. The reaction of Ln(GaMe4)3 (Ln = Y, La, Ce, Nd, Sm, Ho) with HTptBu,Me gave methylidene complexes (TptBu,Me)Ln(μ3-CH2)[(μ-Me)GaMe2]2 (Ln = La, Ce, Nd, Sm) and alkyl complexes (TptBu,Me)LnMe[(μ-Me)GaMe3] (Ln = Y, Ho), while competing B-N bond activation reactions produced GaMe2[BH(Me)(μ-pztBu,Me)2] and (TptBu,Me)Ln(η2-pztBu,Me)[(μ-Me)GaMe3] (Ln = Y, Ho). The steric impact of the TpR,Me ligands was examined by cone angle calculations. Rare-earth-metal methylidene complexes (TptBu,Me)Ln(μ3-CH2)[(μ-Me)EMe2]2 (E = Al, Ga) successfully promote carbonyl methylenation reactions upon addition of ketone.
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Affiliation(s)
- Dorothea Schädle
- Institut für Anorganische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Rannveig Litlabø
- Institut für Anorganische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Department of Chemistry, University of Bergen, Allégaten 41, 5007 Bergen, Norway
| | - Melanie Meermann-Zimmermann
- Institut für Anorganische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Department of Chemistry, University of Bergen, Allégaten 41, 5007 Bergen, Norway
| | - Renita Thim-Spöring
- Institut für Anorganische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Christoph Schädle
- Institut für Anorganische 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
| | - Karl W Törnroos
- Department of Chemistry, University of Bergen, Allégaten 41, 5007 Bergen, Norway
| | - Reiner Anwander
- Institut für Anorganische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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2
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Jiang W, Rajeshkumar T, Guo M, Lin Y, Maron L, Zhang L. Rare-earth metal ethylene and ethyne complexes. Chem Sci 2024; 15:3495-3501. [PMID: 38455028 PMCID: PMC10915835 DOI: 10.1039/d3sc06599e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 01/26/2024] [Indexed: 03/09/2024] Open
Abstract
Guanidinate homometallic rare-earth ethyl complexes [LLn(μ2-η1:η2-Et)(Et)]2 (Ln = Y(1-Y), Lu(1-Lu)) and heterobimetallic rare-earth ethyl complexes LLn(Et)(μ2-η1:η2-Et)(μ2-η1-Et)(AlEt2) (Ln = Y(2-Y), Lu(2-Lu)) have been synthesized by the treatment of LLn(CH2C6H4NMe2-o)2 (L = (PhCH2)2NC(NC6H3iPr2-2,6)2) with different equivalents of AlEt3 in toluene at ambient temperature. Interestingly, the unprecedented rare-earth ethyne complex [LY(μ2-η1-Et)2(AlEt)]2(μ4-η1:η1:η2:η2-C2H2) (3-Y) containing a [C2H2]4- unit was afforded from 2-Y. The formation mechanism study on 3-Y was carried out by DFT calculations. Furthermore, the nature of the bonding of 3-Y was also revealed by NBO analysis. The reactions of LLn(CH2 C6H4NMe2-o)2 (Ln = Y, Lu) with AlEt3 (4 equiv.) in toluene at 50 °C produced firstly the non-Cp rare-earth ethylene complex LY(μ3-η1:η1:η2-C2H4)[(μ2-η1-Et)(AlEt2)(μ2-η1-Et)2(AlEt)] (4-Y), and the Y/Al ethyl complex LY[(μ2-η1-Et)2(AlEt2)]2 (5-Y) as an intermediate of 4-Y was isolated from the reaction of LY(CH2C6H4NMe2-o)2 with AlEt3 (4 equiv.) in toluene at -10 °C.
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Affiliation(s)
- Wen Jiang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University 2005 Songhu Road, Jiangwan Campus Shanghai 200438 P. R. China
| | | | - Mengyue Guo
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University 2005 Songhu Road, Jiangwan Campus Shanghai 200438 P. R. China
| | - Yuejian Lin
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University 2005 Songhu Road, Jiangwan Campus Shanghai 200438 P. R. China
| | | | - Lixin Zhang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University 2005 Songhu Road, Jiangwan Campus Shanghai 200438 P. R. China
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3
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Jiang W, Kong F, Del Rosal I, Li M, Wang K, Maron L, Zhang L. A binuclear guanidinate yttrium carbyne complex: unique reactivity toward unsaturated C-N, C-O and C-S bonds. Chem Sci 2023; 14:9154-9160. [PMID: 37655032 PMCID: PMC10466373 DOI: 10.1039/d3sc03483f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 08/02/2023] [Indexed: 09/02/2023] Open
Abstract
A guanidinato-stabilized binuclear yttrium carbyne complex [(PhCH2)2NC(NC6H3iPr2-2,6)2]2Y2(μ2-Me)(AlMe3)2(μ4-CH) (1) was synthesized via C-H bond activation and its versatile reactivities were investigated. Complex 1 underwent σ-bond metathesis with PhSSPh and nucleophilic addition with PhCN to form the corresponding yttrium thiolate complex 3 and aza-allyl complex 4 respectively. Additionally, the rare yttrium carbide complex 5 was also prepared by treatment of complex 1 with S8. Interestingly, in the reaction with PhNCS, the C[double bond, length as m-dash]S double bond was cleaved, followed by C-H bond activation to give the yttrium sulfide complex 7 with a ketenimine dianion ligand. Unexpectedly, the reaction of complex 1 with CO (1 atm) resulted in deoxygenative coupling of CO, to afford mono- or dioxo-yttrium complexes at different temperatures. The mechanism of the possible formation processes of complexes 3 and 9 was elucidated by DFT calculations.
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Affiliation(s)
- Wen Jiang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University 2005 Songhu Road, Jiangwan Campus Shanghai 200438 P. R. China
| | - Feng Kong
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University 2005 Songhu Road, Jiangwan Campus Shanghai 200438 P. R. China
| | | | - Meng Li
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University 2005 Songhu Road, Jiangwan Campus Shanghai 200438 P. R. China
| | - Kai Wang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University 2005 Songhu Road, Jiangwan Campus Shanghai 200438 P. R. China
| | | | - Lixin Zhang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University 2005 Songhu Road, Jiangwan Campus Shanghai 200438 P. R. China
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4
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Zhang Z, Kang X, Jiang Y, Cai Z, Li S, Cui D. Access to Disentangled Ultrahigh Molecular Weight Polyethylene via a Binuclear Synergic Effect. Angew Chem Int Ed Engl 2023; 62:e202215582. [PMID: 36418237 DOI: 10.1002/anie.202215582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 11/25/2022]
Abstract
Disentangled ultrahigh molecular weight polyethylene (dis-UHMWPE) has excellent processability but can be achieved under extreme conditions. Herein, we report ethylene polymerization with the binuclear half-sandwich scandium complexes C1-Sc2 and C2-Sc2 to afford UHMWPE. C1-Sc2 bearing a short linker shows higher activity and gives higher molecular weight PEs than C2-Sc2 containing a flexible spacer and the mononuclear Sc1 . Strikingly, all UHMWPEs isolated from C1-Sc2 under broad temperature range (25-120 °C) and wide ethylene pressures (2-13 bar) feature very low degree of entanglement as proved by rheological test, DSC annealing study and SEM. These dis-UHMWPEs are facilely mediated solid-state-process at 130 °C and their tensile strength and modulus reach up to 149.2 MPa and 1.5 GPa, respectively. DFT simulations reveal that the formation of dis-UHMWPE is attributed to the binuclear synergic effect and the agostic interaction between the active center and the growing chain.
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Affiliation(s)
- Zhen Zhang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022, Changchun, China.,Department of Materials Science and Engineering, Jilin University, 130022, Changchun, China
| | - Xiaohui Kang
- College of Pharmacy, Dalian Medical University, 116044, Dalian, China
| | - Yang Jiang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022, Changchun, China.,School of Applied Chemistry and Engineering, University of Science and Technology of China, 230026, Hefei, China
| | - Zhongyi Cai
- Department of Materials Science and Engineering, Jilin University, 130022, Changchun, China
| | - Shihui Li
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022, Changchun, China.,School of Applied Chemistry and Engineering, University of Science and Technology of China, 230026, Hefei, China
| | - Dongmei Cui
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022, Changchun, China.,School of Applied Chemistry and Engineering, University of Science and Technology of China, 230026, Hefei, China
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5
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Buschmann DA, Schumacher L, Anwander R. Rare-earth-metal half-sandwich complexes incorporating methyl, methylidene, and hydrido ligands. Chem Commun (Camb) 2022; 58:9132-9135. [PMID: 35880464 DOI: 10.1039/d2cc03532d] [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
Complexes Cp*3Ln3(μ2-CH3)3(μ3-CH2)(μ3-H)(thf)3 (Ln = Y, Dy; Cp* = C5Me5) are formed via elimination of CH4 and C2H4 from the respective trinuclear polymethyl complexes [Cp*Ln(μ2-CH3)2]3, involving the methyl/methylidene complex Cp*3Ln3(μ2-CH3)3(μ3-CH2)(μ3-CH3)(thf)2 as an intermediate. Compound Cp*3Y3(μ2-CH3)3(μ3-CH2)(μ3-H)(thf)3 displays "Schrock-type" nucleophilic carbene reactivity, converting ketones into the corresponding terminal alkenes. Treatment of Cp*3Y3(μ2-CH3)3(μ3-CH2)(μ3-H)(thf)3 with [D4]methanol proved accessibility of all small-group functionalities as indicated by the simultaneous formation of deuterated HD and deuterated methanes CH3D and CH2D2.
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Affiliation(s)
- Dennis A Buschmann
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
| | - Lion Schumacher
- 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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6
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Buschmann DA, Schneider D, Maichle‐Mössmer C, Anwander R. Half‐Sandwich Complexes [Cp′
4
Ln
4
I
8
]
4
(Ln=Ce, Pr):Emergence of Donor‐Free Organolanthanide Nanowheels. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202100862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Dennis A. Buschmann
- Institut für Anorganische Chemie University of Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
| | - David Schneider
- Institut für Anorganische Chemie University of Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
| | - Cäcilia Maichle‐Mössmer
- Institut für Anorganische Chemie University of Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie University of Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
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7
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Jiang W, Zhang L, Zhang L. Reactivity of Mixed Methyl-Aminobenzyl Guanidinate Lutetium Complex towards iPrN=C=N iPr, CS 2 and Ph 2PH. Dalton Trans 2022; 51:12650-12660. [DOI: 10.1039/d2dt02008d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A heteroleptic terminal alkyl lutetium complex stabilized by a bulky guanidinato ligand, LLu(CH2C6H4NMe2-o)(Me)(THF) (1) (L = (PhCH2)2NC(NC6H3iPr2-2,6)2) has been synthesized by treatment of LLu(CH2C6H4NMe2-o)2 with AlMe3 (1 equiv) via an...
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8
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Deng P, Shi X, Gong X, Cheng J. Trinuclear scandium methylidyne complexes stabilized by pentamethylcyclopentadienyl ligands. Chem Commun (Camb) 2021; 57:6436-6439. [PMID: 34095916 DOI: 10.1039/d1cc01645h] [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 first examples of scandium methylidyne complexes [(Cp*)Sc(μ2-X)]3(μ3-CH) (Cp* = C5Me5; X = Br, Me, OMe), free of Lewis acids, can be achieved in high yields from [(Cp*)ScMe2]2 through a facile route. The chemical and geometrical flexibility to incorporate organic substrates indicates a rich chemistry of complex [(Cp*)Sc(μ2-OMe)]3(μ3-CH).
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Affiliation(s)
- Peng Deng
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, No. 5625, Renmin Street, Changchun 130022, China. and University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Xianghui Shi
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, No. 5625, Renmin Street, Changchun 130022, China.
| | - Xun Gong
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, No. 5625, Renmin Street, Changchun 130022, China. and University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Jianhua Cheng
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, No. 5625, Renmin Street, Changchun 130022, China. and University of Science and Technology of China, Hefei, Anhui 230029, China
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9
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Lanthanides and actinides: Annual survey of their organometallic chemistry covering the year 2019. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.213830] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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10
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Münster K, Fecker AC, Raeder J, Freytag M, Jones PG, Walter MD. Enantiomerically Pure Constrained Geometry Complexes of the Rare-Earth Metals Featuring a Dianionic N-Donor Functionalised Pentadienyl Ligand: Synthesis and Characterisation. Chemistry 2020; 26:16098-16110. [PMID: 32735382 PMCID: PMC7756846 DOI: 10.1002/chem.202003170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 07/31/2020] [Indexed: 11/07/2022]
Abstract
We report the preparation of enantiomerically pure constrained geometry complexes (cgc) of the rare-earth metals bearing a pentadienyl moiety (pdl) derived from the natural product (1R)-(-)-myrtenal. The potassium salt 1, [Kpdl*], was treated with ClSiMe2 NHtBu, and the resulting pentadiene 2 was deprotonated with the Schlosser-type base KOtPen/nBuLi (tPen=CMe2 (CH2 Me)) to yield the dipotassium salt [K2 (pdl*SiMe2 NtBu)] (3). However, 3 rearranges in THF solution to its isomer 3' by a 1,3-H shift, which elongates the bridge between the pdl and SiMe2 NtBu moieties by one CH2 unit. This is crucial for the successful formation of various monomeric C1 - or dimeric C2 -symmetric rare-earth cgc complexes with additional halide, tetraborohydride, amido and alkyl functionalities. All compounds have been extensively characterised by solid-state X-ray diffraction analysis, solution NMR spectroscopy and elemental analyses.
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Affiliation(s)
- Katharina Münster
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Ann Christin Fecker
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Jan Raeder
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Matthias Freytag
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Peter G. Jones
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Marc D. Walter
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
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11
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Birkelbach VM, Kracht F, Dietrich HM, Stuhl C, Maichle-Mössmer C, Anwander R. A Rare-Earth-Metal Ensemble of the Tebbe Reagent: Scope of Coligands and Carbonyl Olefination. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00447] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Verena M. Birkelbach
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Felix Kracht
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - H. Martin Dietrich
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Christoph Stuhl
- 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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12
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Buschmann DA, Dietrich HM, Schneider D, Birkelbach VM, Stuhl C, Törnroos KW, Maichle‐Mössmer C, Anwander R. Nanoscale Organolanthanum Clusters: Nuclearity-Directing Role of Cyclopentadienyl and Halogenido Ligands. Chemistry 2020; 26:10834-10840. [PMID: 32329535 PMCID: PMC7496188 DOI: 10.1002/chem.202001482] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Indexed: 11/08/2022]
Abstract
Tetramethylaluminato/halogenido(X) ligand exchange reactions in half-sandwich complexes [CpR La(AlMe4 )2 ] are feasible in non-coordinating solvents and provide access to large coordination clusters of the type [CpR LaX2 ]x . Incomplete exchange reactions generate the hexalanthanum clusters [CpR 6 La6 X8 (AlMe4 )4 ] (CpR =Cp*=C5 Me5 , X=I; CpR =Cp'=C5 H4 SiMe3 , X=Br, I). Treatment of [Cp*La(AlMe4 )2 ] with two equivalents Me3 SiI gave the nonalanthanum cluster [Cp*LaI2 ]9 , while the exhaustive reaction of [Cp'La(AlMe4 )2 ] with the halogenido transfer reagents Me3 GeX and Me3 SiX (X=I, Br, Cl) produced a series of monocyclopentadienyl rare-earth-metal clusters with distinct nuclearity. Depending on the halogenido ion size the homometallic clusters [Cp'LaCl2 ]10 and [Cp'LaX2 ]12 (X=Br, I) could be isolated, whereas different crystallization techniques led to the aggregation of clusters of distinct structural motifs, including the desilylated cyclopentadienyl-bridged cluster [(μ-Cp)2 Cp'8 La8 I14 ] and the heteroaluminato derivative [Cp'10 La10 Br18 (AlBr2 Me2 )2 ]. The use of the Cp' ancillary ligand facilitates cluster characterization by means of NMR spectroscopy.
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Affiliation(s)
- Dennis A. Buschmann
- Institut für Anorganische ChemieEberhard Karls Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - H. Martin Dietrich
- Institut für Anorganische ChemieEberhard Karls Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - David Schneider
- Institut für Anorganische ChemieEberhard Karls Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - Verena M. Birkelbach
- Institut für Anorganische ChemieEberhard Karls Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - Christoph Stuhl
- Institut für Anorganische ChemieEberhard Karls Universität TübingenAuf der Morgenstelle 1872076TübingenGermany
| | - Karl W. Törnroos
- Department of ChemistryUniversity of BergenAllégaten 415007BergenNorway
| | - 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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13
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Evans R. The interpretation of small molecule diffusion coefficients: Quantitative use of diffusion-ordered NMR spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 117:33-69. [PMID: 32471534 DOI: 10.1016/j.pnmrs.2019.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 11/20/2019] [Accepted: 11/20/2019] [Indexed: 06/11/2023]
Abstract
Measuring accurate molecular self-diffusion coefficients, D, by nuclear magnetic resonance (NMR) techniques has become routine as hardware, software and experimental methodologies have all improved. However, the quantitative interpretation of such data remains difficult, particularly for small molecules. This review article first provides a description of, and explanation for, the failure of the Stokes-Einstein equation to accurately predict small molecule diffusion coefficients, before moving on to three broadly complementary methods for their quantitative interpretation. Two are based on power laws, but differ in the nature of the reference molecules used. The third addresses the uncertainties in the Stokes-Einstein equation directly. For all three methods, a wide range of examples are used to show the range of chemistry to which diffusion NMR can be applied, and how best to implement the different methods to obtain quantitative information from the chemical systems studied.
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Affiliation(s)
- Robert Evans
- Aston Institute of Materials Research, School of Engineering and Applied Science, Aston University, Birmingham B4 7ET, United Kingdom.
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Hollfelder CO, Meermann-Zimmermann M, Spiridopoulos G, Werner D, Törnroos KW, Maichle-Mössmer C, Anwander R. C-H-Bond Activation and Isoprene Polymerization Studies Applying Pentamethylcyclopentadienyl-Supported Rare-Earth-Metal Bis(Tetramethylaluminate) and Dimethyl Complexes. Molecules 2019; 24:molecules24203703. [PMID: 31618971 PMCID: PMC6832758 DOI: 10.3390/molecules24203703] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 10/02/2019] [Accepted: 10/03/2019] [Indexed: 11/29/2022] Open
Abstract
As previously shown for lutetium and yttrium, 1,2,3,4,5-pentamethylcyclopentadienyl (C5Me5 = Cp*)-bearing rare-earth metal dimethyl half-sandwich complexes [Cp*LnMe2]3 are now also accessible for holmium, dysprosium, and terbium via tetramethylaluminato cleavage of [Cp*Ln(AlMe4)2] with diethyl ether (Ho, Dy) and tert-butyl methyl ether (TBME) (Tb). C–H-bond activation and ligand redistribution reactions are observed in case of terbium and are dominant for the next larger-sized gadolinium, as evidenced by the formation of mixed methyl/methylidene clusters [(Cp*Ln)5(CH2)(Me)8] and metallocene dimers [Cp*2Ln(AlMe4)]2 (Ln = Tb, Gd). Applying TBME as a “cleaving” reagent can result in both TBME deprotonation and ether cleavage, as shown for the formation of the 24-membered macrocycle [(Cp*Gd)2(Me)(CH2OtBu)2(AlMe4)]4 or monolanthanum complex [Cp*La(AlMe4){Me3Al(CH2)OtBu}] and monoyttrium complex [Cp*Y(AlMe4)(Me3AlOtBu)], respectively. Complexes [Cp*Ln(AlMe4)2] (Ln = Ho, Dy, Tb, Gd) and [Cp*LnMe2]3 (Ln = Ho, Dy) are applied in isoprene and 1,3-butadiene polymerization, upon activation with borates [Ph3C][B(C6F5)4] and [PhNHMe2][B(C6F5)4], as well as borane B(C6F5)3. The trans-directing effect of AlMe3 in the binary systems [Cp*Ln(AlMe4)2]/borate is revealed and further corroborated by the fabrication of high-cis-1,4 polybutadiene (97%) with “aluminum-free” [Cp*DyMe2]3/[Ph3C][B(C6F5)4]. The formation of multimetallic active species is supported by the polymerization activity of pre-isolated cluster [(Cp*Ho)3Me4(CH2)(thf)2].
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Affiliation(s)
| | - Melanie Meermann-Zimmermann
- Institute of Inorganic Chemistry, University of Tübingen, D-72076 Tübingen, Germany.
- Department of Chemistry, University of Bergen, N-5007 Bergen, Norway.
| | | | - Daniel Werner
- Institute of Inorganic Chemistry, University of Tübingen, D-72076 Tübingen, Germany.
| | - Karl W Törnroos
- Department of Chemistry, University of Bergen, N-5007 Bergen, Norway.
| | | | - Reiner Anwander
- Institute of Inorganic Chemistry, University of Tübingen, D-72076 Tübingen, Germany.
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