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Hales DP, Rajeshkumar T, Shiau AA, Rao G, Ouellette ET, Bergman RG, Britt RD, Maron L, Arnold J. Panoply of P: An Array of Rhenium-Phosphorus Complexes Generated from a Transition Metal Anion. Inorg Chem 2024; 63:11296-11310. [PMID: 38836624 DOI: 10.1021/acs.inorgchem.4c01085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
We expand upon the synthetic utility of anionic rhenium complex Na[(BDI)ReCp] (1, BDI = N,N'-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate) to generate several rhenium-phosphorus complexes. Complex 1 reacts in a metathetical manner with chlorophosphines Ph2PCl, MeNHP-Cl, and OHP-Cl to generate XL-type phosphido complexes 2, 3, and 4, respectively (MeNHP-Cl = 2-chloro-1,3-dimethyl-1,3,2-diazaphospholidine; OHP-Cl = 2-chloro-1,3,2-dioxaphospholane). Crystallographic and computational investigations of phosphido triad 2, 3, and 4 reveal that increasing the electronegativity of the phosphorus substituent (C < N < O) results in a shortening and strengthening of the rhenium-phosphorus bond. Complex 1 reacts with iminophosphane Mes*NPCl (Mes* = 2,4,6-tritert-butylphenyl) to generate linear iminophosphanyl complex 5. In the presence of a suitable halide abstraction reagent, 1 reacts with the dichlorophosphine iPr2NPCl2 to afford cationic phosphinidene complex 6+. Complex 6+ may be reduced by one electron to form 6•, a rare example of a stable, paramagnetic phosphinidene complex. Spectroscopic and structural investigations, as well as computational analyses, are employed to elucidate the influence of the phosphorus substituent on the nature of the rhenium-phosphorus bond in 2 through 6. Furthermore, we examine several common analogies employed to understand metal phosphido, phosphinidene, and iminophosphanyl complexes.
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Affiliation(s)
- David P Hales
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Thayalan Rajeshkumar
- LPCNO, INSA Toulouse, Université de Toulouse, 135 Avenue de Rangueil, Toulouse 31077, France
| | - Angela A Shiau
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Guodong Rao
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Erik T Ouellette
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Robert G Bergman
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - R David Britt
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Laurent Maron
- LPCNO, INSA Toulouse, Université de Toulouse, 135 Avenue de Rangueil, Toulouse 31077, France
| | - John Arnold
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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2
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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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3
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Hess KM, Leach IF, Wijtenhorst L, Lee H, Klein JEMN. Valence Tautomerism Induced Proton Coupled Electron Transfer:X-H Bond Oxidation with a Dinuclear Au(II) Hydroxide Complex. Angew Chem Int Ed Engl 2024; 63:e202318916. [PMID: 38324462 DOI: 10.1002/anie.202318916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/25/2024] [Accepted: 02/05/2024] [Indexed: 02/09/2024]
Abstract
We report the preparation and characterization of the dinuclear AuII hydroxide complex AuII 2(L)2(OH)2 (L=N,N'-bis (2,6-dimethyl) phenylformamidinate) and study its reactivity towards weak X-H bonds. Through the interplay of kinetic analysis and computational studies, we demonstrate that the oxidation of cyclohexadiene follows a concerted proton-coupled electron transfer (cPCET) mechanism, a rare type of reactivity for Au complexes. We find that the Au-Au σ-bond undergoes polarization in the PCET event leading to an adjustment of oxidation levels for both Au centers prior to C(sp3)-H bond cleavage. We thus describe the oxidation event as a valence tautomerism-induced PCET where the basicity of one reduced Au-OH unit provides a proton acceptor and the second more oxidized Au center serves as an electron acceptor. The coordination of these events allows for unprecedented radical-type reactivity by a closed shell AuII complex.
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Affiliation(s)
- Kristopher M Hess
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Isaac F Leach
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Lisa Wijtenhorst
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Hangyul Lee
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Johannes E M N Klein
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
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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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5
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Gawron M, Gilch F, Schmidhuber D, Kelly JA, Horsley Downie TM, Jacobi von Wangelin A, Rehbein J, Wolf R. Counterion Effect in Cobaltate-Catalyzed Alkene Hydrogenation. Angew Chem Int Ed Engl 2024; 63:e202315381. [PMID: 38059406 DOI: 10.1002/anie.202315381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 12/08/2023]
Abstract
We show that countercations exert a remarkable influence on the ability of anionic cobaltate salts to catalyze challenging alkene hydrogenations. An evaluation of the catalytic properties of [Cat][Co(η4 -cod)2 ] (Cat=K (1), Na (2), Li (3), (Dep nacnac)Mg (4), and N(n Bu)4 (5); cod=1,5-cyclooctadiene, Dep nacnac={2,6-Et2 C6 H3 NC(CH3 )}2 CH)]) demonstrated that the lithium salt 3 and magnesium salt 4 drastically outperform the other catalysts. Complex 4 was the most active catalyst, which readily promotes the hydrogenation of highly congested alkenes under mild conditions. A plausible catalytic mechanism is proposed based on density functional theory (DFT) investigations. Furthermore, combined molecular dynamics (MD) simulation and DFT studies were used to examine the turnover-limiting migratory insertion step. The results of these studies suggest an active co-catalytic role of the counterion in the hydrogenation reaction through the coordination to cobalt hydride intermediates.
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Affiliation(s)
- Martin Gawron
- Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany
| | - Franziska Gilch
- Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany
| | - Daniel Schmidhuber
- Institute of Organic Chemistry, University of Regensburg, 93040, Regensburg, Germany
| | - John A Kelly
- Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany
| | | | | | - Julia Rehbein
- Institute of Organic Chemistry, University of Regensburg, 93040, Regensburg, Germany
| | - Robert Wolf
- Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany
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6
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Leitner D, Wittwer B, Neururer FR, Seidl M, Wurst K, Tambornino F, Hohloch S. Expanding the Utility of β-Diketiminate Ligands in Heavy Group VI Chemistry of Molybdenum and Tungsten. Organometallics 2023; 42:1411-1424. [PMID: 37388273 PMCID: PMC10302891 DOI: 10.1021/acs.organomet.3c00056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Indexed: 07/01/2023]
Abstract
We report the synthesis of 17 molybdenum and tungsten complexes supported by the ubiquitous BDI ligand framework (BDI = β-diketiminate). The focal entry point is the synthesis of four molybdenum and tungsten(V) BDI complexes of the general formula [MO(BDIR)Cl2] [M = Mo, R = Dipp (1); M = W, R = Dipp (2); M = Mo, R = Mes (3); M = W, R = Mes (4)] synthesized by the reaction between MoOCl3(THF)2 or WOCl3(THF)2 and LiBDIR. Reactivity studies show that the BDIDipp complexes are excellent precursors toward adduct formation, reacting smoothly with dimethylaminopyridine (DMAP) and triethylphosphine oxide (OPEt3). No reaction with small phosphines has been observed, strongly contrasting the chemistry of previously reported rhenium(V) complexes. Additionally, the complexes 1 and 2 are good precursors for salt metathesis reactions. While 1 can be chemically reduced to the first stable example of a Mo(IV) BDI complex 15, reduction of 2 resulted in degradation of the BDI ligand via a nitrene transfer reaction, leading to MAD (4-((2,6-diisopropylphenyl)imino)pent-2-enide) supported tungsten(V) and tungsten(VI) complexes 16 and 17. All reported complexes have been thoroughly studied by VT-NMR and (heteronuclear) NMR spectroscopy, as well as UV-vis and EPR spectroscopy, IR spectroscopy, and X-ray diffraction analysis.
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Affiliation(s)
- Daniel Leitner
- Faculty
of Chemistry and Pharmacy, Institute for General, Inorganic and Theoretical
Chemistry, University of Innsbruck, Innrain 80−82, Innsbruck 6020 Austria
| | - Benjamin Wittwer
- Faculty
of Chemistry and Pharmacy, Institute for General, Inorganic and Theoretical
Chemistry, University of Innsbruck, Innrain 80−82, Innsbruck 6020 Austria
| | - Florian R. Neururer
- Faculty
of Chemistry and Pharmacy, Institute for General, Inorganic and Theoretical
Chemistry, University of Innsbruck, Innrain 80−82, Innsbruck 6020 Austria
| | - Michael Seidl
- Faculty
of Chemistry and Pharmacy, Institute for General, Inorganic and Theoretical
Chemistry, University of Innsbruck, Innrain 80−82, Innsbruck 6020 Austria
| | - Klaus Wurst
- Faculty
of Chemistry and Pharmacy, Institute for General, Inorganic and Theoretical
Chemistry, University of Innsbruck, Innrain 80−82, Innsbruck 6020 Austria
| | - Frank Tambornino
- Fachbereich
Chemie and Wissenschaftlichen Zentrum für Materialwissenschaften
(WZMW), Phillips-University Marburg, Hans-Meerwein-Straße 4, 35043 Marburg, Germany
| | - Stephan Hohloch
- Faculty
of Chemistry and Pharmacy, Institute for General, Inorganic and Theoretical
Chemistry, University of Innsbruck, Innrain 80−82, Innsbruck 6020 Austria
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7
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Ouellette ET, Magdalenski JS, Bergman RG, Arnold J. Heterobimetallic-Mediated Dinitrogen Functionalization: N-C Bond Formation at Rhenium-Group 9 Diazenido Complexes. Inorg Chem 2022; 61:16064-16071. [PMID: 36150135 DOI: 10.1021/acs.inorgchem.2c02463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the synthesis and characterization of rhenium-group 9 heterobimetallic diazenido species (η5-Cp)Re(μ-BDI)(μ-N2)M(η4-COD) (1-M, M = Ir or Rh, Cp = cyclopentadienide, BDI = N,N'-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate, COD = 1,5-cyclooctadiene), formed from salt elimination reactions between Na[(η5-Cp)Re(BDI)] and [MCl(η4-COD)]2. Additionally, we find that these same reagents react under an argon atmosphere to instead produce bridging hydride complexes (BDI)Re(μ-η5:η1-C5H4)(μ-H)M(η4-COD) (2-M), which undergo rearrangements upon protonation to form the alternative bridging hydrides [(η5-Cp)Re(μ-BDI)(μ-H)M(η4-COD)][(B(m-C6H3(CF3)2)4)] (3-M). Further, we demonstrate the first example of N-C bond formation at a heterobimetallic dinitrogen complex through reactions of 1-M and methyl triflate, which produces the alkylated species [(η5-Cp)Re(μ-N(Me)N)(μ-BDI)M(η4-COD)][OTf] (4-M, OTf = trifluoromethanesulfonate). A combination of spectroscopic studies, X-ray structural analysis, and computational investigations is discussed as an aid to understanding the modes of dinitrogen activation within these unique heterobimetallic complexes.
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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
| | - Julian S Magdalenski
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - 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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Suhr S, Walter R, Beerhues J, Albold U, Sarkar B. Rhodium Diamidobenzene Complexes: A Tale of Different Substituents on the Diamidobenzene Ligand. Chem Sci 2022; 13:10532-10545. [PMID: 36277629 PMCID: PMC9473529 DOI: 10.1039/d2sc03227a] [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: 06/08/2022] [Accepted: 07/15/2022] [Indexed: 11/21/2022] Open
Abstract
Diamidobenzene ligands are a prominent class of redox-active ligands owing to their electron reservoir behaviour, as well as the possibility of tuning the steric and the electronic properties of such ligands through the substituents on the N-atoms of the ligands. In this contribution, we present Rh(iii) complexes with four differently substituted diamidobenzene ligands. By using a combination of crystallography, NMR spectroscopy, electrochemistry, UV-vis-NIR/EPR spectroelectrochemistry, and quantum chemical calculations we show that the substituents on the ligands have a profound influence on the bonding, donor, electrochemical and spectroscopic properties of the Rh complexes. We present, for the first time, design strategies for the isolation of mononuclear Rh(ii) metallates whose redox potentials span across more than 850 mV. These Rh(ii) metallates undergo typical metalloradical reactivity such as activation of O2 and C–Cl bond activations. Additionally, we also show that the substituents on the ligands dictate the one versus two electron nature of the oxidation steps of the Rh complexes. Furthermore, the oxidative reactivity of the metal complexes with a [CH3]+ source leads to the isolation of a unprecedented, homobimetallic, heterovalent complex featuring a novel π-bonded rhodio-o-diiminoquionone. Our results thus reveal several new potentials of the diamidobenzene ligand class in organometallic reactivity and small molecule activation with potential relevance for catalysis. Diamidobenzene ligands are versatile platforms in organometallic Rh-chemistry. They allow the isolation of tunable mononuclear ate-complexes, and the formation of a unprecedented homobimetallic, heterovalent complex.![]()
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Affiliation(s)
- Simon Suhr
- Lehrstuhl für Anorganische Koordinationschemie, Institut für Anorganische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Robert Walter
- Lehrstuhl für Anorganische Koordinationschemie, Institut für Anorganische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Julia Beerhues
- Lehrstuhl für Anorganische Koordinationschemie, Institut für Anorganische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Uta Albold
- Institut für Chemie und Biochemie, Freie Universität Berlin Fabeckstr. 34-36 14195 Berlin Germany
| | - Biprajit Sarkar
- Lehrstuhl für Anorganische Koordinationschemie, Institut für Anorganische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
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