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Modder DK, Scopelliti R, Mazzanti M. Accessing a Highly Reducing Uranium(III) Complex through Cyclometalation. Inorg Chem 2024; 63:9527-9538. [PMID: 38217471 DOI: 10.1021/acs.inorgchem.3c03668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2024]
Abstract
U(IV) cyclometalated complexes have shown rich reactivity, but their low oxidation state analogues still remain rare. Herein, we report the isolation of [K(2.2.2-cryptand)][UIII{N(SiMe3)2}2(κ2-C,N-CH2SiMe2NSiMe3)], 1, from the reduction of [UIII{N(SiMe)2}3] with KC8 and 2.2.2-cryptand at room temperature. Cyclic voltammetry studies demonstrate that 1 has a reduction potential similar to that of the previously reported [K(2.2.2-cryptand)][UII{N(SiMe)2}3] (Epc = -2.6 V versus Fc+/0 and Epc = -2.8 V versus Fc+/0, respectively). Complex 1, indeed, shows similar reducing abilities upon reactions with 4,4'-bipyridine, 2,2'-bipyridine, and 1-azidoadamantane. Interestingly, 1 was also found to be the first example of a mononuclear U(III) complex that is capable of reducing pyridine. In addition, it is shown that a wide variety of substrates can be inserted into the U-C bond, forming new U(III) metallacycles. These results highlight that cyclometalated U(III) complexes can serve as versatile precursors for a broad range of reactivity and for assembling a variety of novel chemical architectures.
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Affiliation(s)
- Dieuwertje K Modder
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Rosario Scopelliti
- Group of Coordination Chemistry, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, 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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2
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Landaeta VR, Horsley Downie TM, Wolf R. Low-Valent Transition Metalate Anions in Synthesis, Small Molecule Activation, and Catalysis. Chem Rev 2024; 124:1323-1463. [PMID: 38354371 PMCID: PMC10906008 DOI: 10.1021/acs.chemrev.3c00121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 10/09/2023] [Accepted: 10/09/2023] [Indexed: 02/16/2024]
Abstract
This review surveys the synthesis and reactivity of low-oxidation state metalate anions of the d-block elements, with an emphasis on contributions reported between 2006 and 2022. Although the field has a long and rich history, the chemistry of transition metalate anions has been greatly enhanced in the last 15 years by the application of advanced concepts in complex synthesis and ligand design. In recent years, the potential of highly reactive metalate complexes in the fields of small molecule activation and homogeneous catalysis has become increasingly evident. Consequently, exciting applications in small molecule activation have been developed, including in catalytic transformations. This article intends to guide the reader through the fascinating world of low-valent transition metalates. The first part of the review describes the synthesis and reactivity of d-block metalates stabilized by an assortment of ligand frameworks, including carbonyls, isocyanides, alkenes and polyarenes, phosphines and phosphorus heterocycles, amides, and redox-active nitrogen-based ligands. Thereby, the reader will be familiarized with the impact of different ligand types on the physical and chemical properties of metalates. In addition, ion-pairing interactions and metal-metal bonding may have a dramatic influence on metalate structures and reactivities. The complex ramifications of these effects are examined in a separate section. The second part of the review is devoted to the reactivity of the metalates toward small inorganic molecules such as H2, N2, CO, CO2, P4 and related species. It is shown that the use of highly electron-rich and reactive metalates in small molecule activation translates into impressive catalytic properties in the hydrogenation of organic molecules and the reduction of N2, CO, and CO2. The results discussed in this review illustrate that the potential of transition metalate anions is increasingly being tapped for challenging catalytic processes with relevance to organic synthesis and energy conversion. Therefore, it is hoped that this review will serve as a useful resource to inspire further developments in this dynamic research field.
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Affiliation(s)
| | | | - Robert Wolf
- University of Regensburg, Institute
of Inorganic Chemistry, 93040 Regensburg, Germany
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3
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Queen JD, Anderson-Sanchez LM, Stennett CR, Rajabi A, Ziller JW, Furche F, Evans WJ. Synthesis of Crystallographically Characterizable Bis(cyclopentadienyl) Sc(II) Complexes: (C 5H 2tBu 3) 2Sc and {[C 5H 3(SiMe 3) 2] 2ScI} 1. J Am Chem Soc 2024; 146:3279-3292. [PMID: 38264991 DOI: 10.1021/jacs.3c11922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
The synthesis of previously unknown bis(cyclopentadienyl) complexes of the first transition metal, i.e., Sc(II) scandocene complexes, has been investigated using C5H2(tBu)3 (Cpttt), C5Me5 (Cp*), and C5H3(SiMe3)2 (Cp″) ligands. Cpttt2ScI, 1, formed from ScI3 and KCpttt, can be reduced with potassium graphite (KC8) in hexanes to generate dark-red crystals of the first crystallographically characterizable bis(cyclopentadienyl) scandium(II) complex, Cpttt2Sc, 2. Complex 2 has a 170.6° (ring centroid)-Sc-(ring centroid) angle and exhibits an eight-line EPR spectrum characteristic of Sc(II) with Aiso = 82.6 MHz (29.6 G). It sublimes at 200 °C at 10-4 Torr and has a melting point of 268-271 °C. Reductions of Cp*2ScI and Cp″2ScI under analogous conditions in hexanes did not provide new Sc(II) complexes, and reduction of Cp*2ScI in benzene formed the Sc(III) phenyl complex, Cp*2Sc(C6H5), 3, by C-H bond activation. However, in Et2O and toluene, reduction of Cp*2ScI at -78 °C gives a dark-red solution, 4, which displays an eight-line EPR pattern like that of 1, but it did not provide thermally stable crystals. Reduction of Cp″2ScI, in THF or Et2O at -35 °C in the presence of 2.2.2-cryptand, yields the green Sc(II) metallocene iodide complex, [K(crypt)][Cp″2ScI], 5, which was identified by X-ray crystallography and EPR spectroscopy and is thermally unstable. The analogous reaction of Cp*2ScI with KC8 and 18-crown-6 in Et2O gave the ligand redistribution product, [Cp*2Sc(18-crown-6-κ2O,O')][Cp*2ScI2], 6, as the only crystalline product. Density functional theory calculations on the electronic structure of these compounds are reported in addition to a steric analysis using the Guzei method.
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Affiliation(s)
- Joshua D Queen
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | | | - Cary R Stennett
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Ahmadreza Rajabi
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Joseph W Ziller
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Filipp Furche
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - William J Evans
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
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4
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Jena R, Benner F, Delano F, Holmes D, McCracken J, Demir S, Odom AL. A rare isocyanide derived from an unprecedented neutral yttrium(ii) bis(amide) complex. Chem Sci 2023; 14:4257-4264. [PMID: 37123180 PMCID: PMC10132164 DOI: 10.1039/d3sc00171g] [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: 01/10/2023] [Accepted: 03/11/2023] [Indexed: 05/02/2023] Open
Abstract
A room temperature stable complex formulated as Y(NHAr*)2 has been prepared, where Ar* = 2,6-(2,4,6-(iPr)3C6H2)C6H3, by KC8 reduction of ClY(NHAr*)2. Based on EPR evidence, Y(NHAr*)2 is an example of a d1 Y(ii) complex with significant delocalization of the unpaired electron density from the metal to the ligand. The isolation of molecular divalent metal complexes is challenging for rare earth elements such as yttrium. In fact, stabilization of the divalent state requires judicious ligand design that allows the metal center to be coordinatively saturated. Divalent rare earth elements tend to be reactive towards various substrates. Interestingly, Y(NHAr*)2 reacts as a radical donor towards t BuNC to generate an unusual yttrium isocyanide complex, CNY(NHAr*)2, based on spectroscopic evidence and single-crystal X-ray diffraction data.
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Affiliation(s)
- Rashmi Jena
- Michigan State University, Department of Chemistry 578 S. Shaw Ln East Lansing MI USA 48824
| | - Florian Benner
- Michigan State University, Department of Chemistry 578 S. Shaw Ln East Lansing MI USA 48824
| | - Francis Delano
- Michigan State University, Department of Chemistry 578 S. Shaw Ln East Lansing MI USA 48824
| | - Daniel Holmes
- Michigan State University, Department of Chemistry 578 S. Shaw Ln East Lansing MI USA 48824
| | - John McCracken
- Michigan State University, Department of Chemistry 578 S. Shaw Ln East Lansing MI USA 48824
| | - Selvan Demir
- Michigan State University, Department of Chemistry 578 S. Shaw Ln East Lansing MI USA 48824
| | - Aaron L Odom
- Michigan State University, Department of Chemistry 578 S. Shaw Ln East Lansing MI USA 48824
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Moore WNG, White JRK, Wedal JC, Furche F, Evans WJ. Reduction of Rare-Earth Metal Complexes Induced by γ Irradiation. Inorg Chem 2022; 61:17713-17718. [DOI: 10.1021/acs.inorgchem.2c02857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- William N. G. Moore
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Jessica R. K. White
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Justin C. Wedal
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Filipp Furche
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - William J. Evans
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
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6
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Wedal JC, Ziller JW, Furche F, Evans WJ. Synthesis and Reduction of Heteroleptic Bis(cyclopentadienyl) Uranium(III) Complexes. Inorg Chem 2022; 61:7365-7376. [PMID: 35504019 DOI: 10.1021/acs.inorgchem.2c00322] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Heteroleptic U(III) complexes supported by bis(cyclopentadienyl) frameworks have been synthesized to examine their suitability as precursors to U(II) complexes. The newly synthesized (C5Me5)2U(OC6H2tBu2-2,6-Me-4), (C5Me5)2U(OC6H2Ad2-2,6-tBu-4) (Ad = 1-adamantyl), (C5Me5)2U(C5H5), and (C5Me5)2U(C5Me4H) are compared with (C5Me5)2U[N(SiMe3)2], (C5Me5)2U[CH(SiMe3)2], and (C5Me5)U[N(SiMe3)2]2. An improved synthesis of (C5Me5)2U(μ-Ph)2BPh2 was developed, which was used to synthesize (C5Me5)2U(C5Me4H). Since the X-ray crystal structure of (C5Me5)2U(OC6H2tBu2-2,6-Me-4) contained two very different molecules in the asymmetric unit with 115.7(5)° and 166.0(5)° U-O-Cipso angles, the (C5Me4H)2U(OC6H2tBu2-2,6-Me-4) and (C5Me5)2Ce(OC6H2tBu2-2,6-Me-4) analogues were synthesized and characterized by X-ray diffraction for comparison. Electrochemical studies in THF with a 100 mM [nBu4N][BPh4] supporting electrolyte showed U(IV)/U(III) and U(III)/U(II) redox couples for all the heteroleptic complexes except (C5Me5)2U(C5H5). Chemical reduction of all heteroleptic compounds formed dark blue solutions characteristic of U(II) when reacted with KC8 at -78 °C, but none formed isolable U(II) complexes. The targeted U(II) complexes, [(C5Me5)2U(OC6H2tBu2-2,6-Me-4)]1-, {(C5Me5)2U[CH(SiMe3)2]}1-, [(C5Me5)2U(C5H5)]1-, and [(C5Me5)2U(C5Me4H)]1-, were analyzed by density functional theory, and a 5f36d1 electron configuration was found to be the ground state in each case.
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Affiliation(s)
- Justin C Wedal
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Joseph W Ziller
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Filipp Furche
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - William J Evans
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
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Seth K. Recent progress in rare-earth metal-catalyzed sp 2 and sp 3 C–H functionalization to construct C–C and C–heteroelement bonds. Org Chem Front 2022. [DOI: 10.1039/d1qo01859k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The review presents rare-earth metal-catalyzed C(sp2/sp3)–H functionalization accessing C–C/C–heteroatom bonds and olefin (co)polymerization, highlighting substrate scope, mechanistic realization, and origin of site-, enantio-/diastereo-selectivity.
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Affiliation(s)
- Kapileswar Seth
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER) – Guwahati, Sila Katamur, Changsari, Kamrup 781101, Assam, India
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