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Bischoff IA, Danés S, Thoni P, Morgenstern B, Andrada DM, Müller C, Lambert J, Gießelmann ECJ, Zimmer M, Schäfer A. A lithium-aluminium heterobimetallic dimetallocene. Nat Chem 2024; 16:1093-1100. [PMID: 38744915 DOI: 10.1038/s41557-024-01531-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 04/05/2024] [Indexed: 05/16/2024]
Abstract
Homobimetallic dimetallocenes exhibiting two identical metal atoms sandwiched between two η5 bonded cyclopentadienyl rings is a narrow class of compounds, with representative examples being dizincocene and diberyllocene. Here we report the synthesis and structural characterization of a heterobimetallic dimetallocene, accessible through heterocoupling of lithium and aluminylene fragments with pentaisopropylcyclopentadienyl ligands. The Al-Li bond features a high ionic character and profits from attractive dispersion interactions between the isopropyl groups of the cyclopentadienyl ligands. A key synthetic step is the isolation of a cyclopentadienylaluminylene monomer, which also enables the structural characterization of this species. In addition to their structural authentication by single-crystal X-ray diffraction analysis, both compounds were characterized by multinuclear NMR spectroscopy in solution and in the solid state. Furthermore, reactivity studies of the lithium-aluminium heterobimetallic dimetallocene with an N-heterocyclic carbene and different heteroallenes were performed and show that the Al-Li bond is easily cleaved.
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Affiliation(s)
- Inga-Alexandra Bischoff
- Department of Chemistry, Faculty of Natural Sciences and Technology, Saarland University, Saarbrücken, Germany
| | - Sergi Danés
- Department of Chemistry, Faculty of Natural Sciences and Technology, Saarland University, Saarbrücken, Germany
| | - Philipp Thoni
- Department of Chemistry, Faculty of Natural Sciences and Technology, Saarland University, Saarbrücken, Germany
| | - Bernd Morgenstern
- Department of Chemistry, Faculty of Natural Sciences and Technology, Saarland University, Saarbrücken, Germany
| | - Diego M Andrada
- Department of Chemistry, Faculty of Natural Sciences and Technology, Saarland University, Saarbrücken, Germany
| | - Carsten Müller
- Department of Chemistry, Faculty of Natural Sciences and Technology, Saarland University, Saarbrücken, Germany
| | - Jessica Lambert
- Department of Chemistry, Faculty of Natural Sciences and Technology, Saarland University, Saarbrücken, Germany
| | - Elias C J Gießelmann
- Department of Chemistry, Faculty of Natural Sciences and Technology, Saarland University, Saarbrücken, Germany
| | - Michael Zimmer
- Department of Chemistry, Faculty of Natural Sciences and Technology, Saarland University, Saarbrücken, Germany
| | - André Schäfer
- Department of Chemistry, Faculty of Natural Sciences and Technology, Saarland University, Saarbrücken, Germany.
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Choi H, Yoo S, Song H, Lee E. IZCp and PZCp: Redox Non-innocent Cyclopentadienyl Ligands as Electron Reservoirs for Sandwich Complexes. Inorg Chem 2024; 63:6427-6434. [PMID: 38534011 DOI: 10.1021/acs.inorgchem.4c00259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
A long-sustained effort of systematic steric and electronic modification of cyclopentadienyl (Cp) ligands has enabled them to find wide-ranging, valuable applications. Herein, we present two novel Cp ligands: imidazolium- and pyrrolinium-substituted zwitterionic Cps (IZCp and PZCp), whose key utility is redox non-innocence─the ability to participate cooperatively with the metal center in redox reactions. Through the simple metalation of ZCps, the Cr(0) and Mo(0) half-sandwich complexes (IZCp)Cr(CO)3, (PZCp)Cr(CO)3, (IZCp)Mo(CO)3, and (PZCp)Mo(CO)3, respectively, as well as the Ru(II) sandwich complexes [(IZCp)RuCp]PF6 and [(PZCp)RuCp]PF6 were prepared. The sandwich complexes were fully characterized and showed by cyclic voltammetry reversible one-electron reduction at E1/2 potentials ranging from -1.7 to -2.7 V vs Fc/Fc+. These values are unusually low and have not been observed with other Cp ligands due to the instability of the reduced complexes. Density functional theory (DFT) calculations for the reduced sandwich derivatives with IZCp and PZCp showed their spin densities to be highly delocalized over their ZCp ligand moieties (70-90%). Electron paramagnetic resonance (EPR) analysis of the isolated K[(PZCp)Mo(CO)3] and (PZCp)RuCp also indicated a high degree of ligand-localized radical character. Thus, the IZCp and PZCp ligands act as electron reservoirs to sustain these sandwich complexes in highly reduced states. At the same time, the CO stretching frequencies of K[(PZCp)Mo(CO)3]: νCO 1871, 1748, and 1699 cm-1, rank the [PZCp]- ligand as the strongest electron-donating Cp ligand among the reported CpMo(CO)3 derivatives, whose νCO > 1746 cm-1. In addition, these redox non-innocent Cps were obtained in high yields and found to be practically air- and moisture-stable, unlike typical Cps.
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Affiliation(s)
- Hyeonjeong Choi
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Seunghyuk Yoo
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Hayoung Song
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
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Vollgraff T, Doppiu A, Sundermeyer J. Dihydroguaiazulenide Complexes and Catalysts of Group 8-12 Transition Metals: Ligands from Renewable Feedstock Replace, even Outmatch Petrochemical Based Cyclopentadienyl Chemistry. Chemistry 2024; 30:e202302994. [PMID: 37955549 DOI: 10.1002/chem.202302994] [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: 09/14/2023] [Revised: 11/09/2023] [Accepted: 11/09/2023] [Indexed: 11/14/2023]
Abstract
We present an in-depth study of the sterically demanding Cp-synthon (8-H-GuaH)Li isolated from natural product guaiazulene (Gua) as a ligand transfer reagent towards late transition metal complex precursors. The synthesis and full characterization of selected, essentially unexplored homo- and heteroleptic 8-H-guaiazulenide complexes of iron, ruthenium, cobalt, rhodium, platinum, copper and zinc are discussed in detail. In order to demonstrate their potential in catalytic applications, [(GuaH)PtMe3 ] was selected. The latter proved an even higher catalytic activity in light induced olefin hydrosilylation at catalyst loads as low as 5 ppm than classical [CpPtMe3 ] in a typical test reaction of silicone elastomer fabrication. Our results demonstrate that traditional petrochemical based Cp metal chemistry and catalysis can be replaced, sometimes even outmatched by superior catalysts based on cheap building blocks from renewable feedstock.
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Affiliation(s)
- Tobias Vollgraff
- Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35043, Marburg, Germany
| | - Angelino Doppiu
- Umicore AG&Co. KG, PMC R&D, Rodenbacher Chaussee 4, 63457, Hanau-Wolfgang, Germany
| | - Jörg Sundermeyer
- Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35043, Marburg, Germany
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Arumugam S, Schwarz B, Ravichandran P, Kumar S, Ungur L, Mondal KC. Dipotassiumtetrachloride-bridged dysprosium metallocenes: a single-molecule magnet. Dalton Trans 2023; 52:15326-15333. [PMID: 37387215 DOI: 10.1039/d3dt01325a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
The present work describes the dynamic magnetic properties of the complex [(CpAr3)4DyIII2Cl4K2]·3.5(C7H8) (1), synthesized by employing a tri-aryl-substituted cyclopentadienyl ligand (CpAr3), [4,4'-(4-phenylcyclopenta-1,3-diene-1,2-diyl)bis(methylbenzene) = CpAr3H]. Each Dy(III)-metallocene weakly couples via K2Cl4, displaying slow relaxation of magnetization below 14.5 K under zero applied dc field via KD3 energy levels with an energy barrier of 136.9/133.7 cm-1 on the Dy sites. The single-ion axial anisotropy energy barrier is reduced by geometrical distortion due to the coordination of two chloride ions at each Dy centre.
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Affiliation(s)
- Selvakumar Arumugam
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, India.
| | - Björn Schwarz
- Institute for Applied Materials - Energy Storage Systems (IAM-ESS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
| | | | - Sunil Kumar
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, India.
| | - Liviu Ungur
- Department of Chemistry, National University of Singapore, Singapore.
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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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Pavun A, Kopacka H, Wurst K, Müller T, Neururer FR, Hohloch S, Bildstein B. Tromancenium complexes with steric and electronic modulation. J Organomet Chem 2022. [DOI: 10.1016/j.jorganchem.2022.122594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Sievers R, Sellin M, Rupf SM, Parche J, Malischewski M. Introducing the Perfluorinated Cp* Ligand into Coordination Chemistry. Angew Chem Int Ed Engl 2022; 61:e202211147. [PMID: 35984742 PMCID: PMC9826324 DOI: 10.1002/anie.202211147] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Indexed: 01/11/2023]
Abstract
The reaction of AgBF4 and [Rh(COD)Cl]2 (COD=1,5-cyclooctadiene) in presence of [NEt4 ][C5 (CF3 )5 ] afforded the fluorocarbon soluble complex [Rh(COD)(C5 (CF3 )5 )] by salt metathesis. This complex represents the first example for a successful coordination of the weakly basic [C5 (CF3 )5 ]- ligand, since its first synthesis in 1980. In addition to [Rh(COD)(C5 (CF3 )5 )] also the byproduct [Rh(COD)(C5 (CF3 )4 H)] was isolated and fully characterized. Accompanying DFT studies showed that the interaction energy of the [C5 (CF3 )5 ]- ligand towards the 12-electron fragment [Rh(COD)]+ is ≈70 kcal mol-1 lower in comparison to [C5 (CH3 )5 ]- due to reduced electrostatic interactions and weaker π-donor properties of the ligand. The quantitative but reversible substitution of the [C5 (CF3 )5 ]- ligand by toluene, converting it into a weakly coordinating anion, experimentally proved the extraordinary weak bonding interaction.
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Affiliation(s)
- Robin Sievers
- Freie Universität BerlinInstitut für Chemie und Biochemie, Anorganische ChemieFabeckstraße 34–3614195BerlinGermany
| | - Malte Sellin
- Freie Universität BerlinInstitut für Chemie und Biochemie, Anorganische ChemieFabeckstraße 34–3614195BerlinGermany,Albert-Ludwigs-Universität FreiburgInstitut für Anorganische und Analytische ChemieAlbertstraße 2179104FreiburgGermany
| | - Susanne M. Rupf
- Freie Universität BerlinInstitut für Chemie und Biochemie, Anorganische ChemieFabeckstraße 34–3614195BerlinGermany
| | - Joshua Parche
- Freie Universität BerlinInstitut für Chemie und Biochemie, Anorganische ChemieFabeckstraße 34–3614195BerlinGermany
| | - Moritz Malischewski
- Freie Universität BerlinInstitut für Chemie und Biochemie, Anorganische ChemieFabeckstraße 34–3614195BerlinGermany
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Sievers R, Sellin M, Rupf SM, Parche J, Malischewski M. Introducing the Perfluorinated Cp* Ligand into Coordination Chemistry. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202211147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Robin Sievers
- Freie Universität Berlin: Freie Universitat Berlin Institut für Chemie und Biochemie GERMANY
| | - Malte Sellin
- Albert-Ludwigs-Universität Freiburg: Albert-Ludwigs-Universitat Freiburg Institut für Anorganische und Analytische Chemie GERMANY
| | - Susanne M. Rupf
- Freie Universität Berlin: Freie Universitat Berlin Institut für Chemie und Biochemie GERMANY
| | - Joshua Parche
- Freie Universität Berlin: Freie Universitat Berlin Institut für Chemie und Biochemie GERMANY
| | - Moritz Malischewski
- Freie Universität Berlin - Institut für Chemie und Biochemie Anorganische Chemie Fabeckstrasse 34-36 14195 Berlin GERMANY
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Hierlmeier G, Wolf R. Bulking up Cp BIG: A Penta-Terphenyl Cyclopentadienyl Ligand. Organometallics 2022; 41:776-784. [PMID: 35368714 PMCID: PMC8965875 DOI: 10.1021/acs.organomet.2c00009] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Indexed: 12/13/2022]
Abstract
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The modification
of cyclopentadienyl ligands with carefully selected
substituents is a widely used strategy for tuning their steric
and electronic properties. We describe the synthesis of an extremely
bulky penta-terphenyl cyclopentadienyl ligand (CpT5) by
arylation of cyclopentadiene. Deprotonation reactions with various
group 1 metals and bases afforded a complete series of alkali metal
salts MCpT5 (M = Li–Cs). The compounds were isolated
as solvate-free salts, which were characterized by multinuclear nuclear
magnetic resonance spectroscopy, ultraviolet–visible spectroscopy,
and elemental analysis. Single-crystal X-ray diffraction studies of
LiCpT5, NaCpT5 (crystallized as a solvate with
one tetrahydrofuran molecule per formula unit), and KCpT5 revealed the formation of metallocene-like sandwich structures in
the solid state.
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Affiliation(s)
- Gabriele Hierlmeier
- Institute of Inorganic Chemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Robert Wolf
- Institute of Inorganic Chemistry, University of Regensburg, 93040 Regensburg, Germany
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