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Abstract
In this report, we present intricate pathways for the synthesis of linear nickel(I) silylamide K{m}[Ni(NR2)2] (NR2 = -N(SiMe3)2). This is achieved first via the reduction of nickel(II) trisamide Li(donor)4[Ni(NR2)3] (Li(thf)x[1]) with KC8 in the presence of 18-crown-6 or crypt.222. In due course, the behavior of Li(donor)4[Ni(NR2)3] as a source of masked two-coordinate nickel(II) hexamethyldisilazanide is explored, leading to the formation of nickel(I) and nickel(II) N-donor adducts, as well as metal-metal-bonded dinickel(I) trisamide K(toluene)[Ni2(NR2)3] (K(toluene)[5]). Finally, a convenient and reliable synthesis of K{m}[Ni(NR2)2] by ligand exchange of phosphines in [Ni(NR2)(PPh3)2] with K{m}(NR2) is presented. This allows for the comprehensive analysis of its electronic properties which reveals a fluxional behavior in solution with tight anion/cation interactions.
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Affiliation(s)
- Alexander Reckziegel
- Department of Chemistry, Philipps University Marburg, Hans-Meerwein Straße 4, D-35037 Marburg, Germany
| | - Beatrice Battistella
- Institute of Chemistry, Humboldt-University Berlin, Brook-Taylor-Str. 2, D-12489 Berlin, Germany
| | - Andreas Schmidt
- Department of Chemistry, Philipps University Marburg, Hans-Meerwein Straße 4, D-35037 Marburg, Germany
| | - C Gunnar Werncke
- Department of Chemistry, Philipps University Marburg, Hans-Meerwein Straße 4, D-35037 Marburg, Germany
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Reckziegel A, Battistella B, Werncke G. On the Synthesis of a T‐shaped Imido Nickel Silylamide and Elusive Trigonal Amido Nickel Complexes. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202101102] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Beatrice Battistella
- Humboldt-Universität zu Berlin: Humboldt-Universitat zu Berlin Department of Chemistry GERMANY
| | - Gunnar Werncke
- Philipps-Universität Marburg Fachbereich Chemie Hans-Meerwein-Straße 4 35032 Marburg GERMANY
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3
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Reith S, Demeshko S, Battistella B, Reckziegel A, Schneider C, Stoy A, Lichtenberg C, Meyer F, Munz D, Werncke CG. Between imide, imidyl and nitrene – an imido iron complex in two oxidation states. Chem Sci 2022; 13:7907-7913. [PMID: 35865905 PMCID: PMC9258327 DOI: 10.1039/d2sc01088g] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 05/28/2022] [Indexed: 01/11/2023] Open
Abstract
Imidyl and nitrene metal species play an important role in the N-functionalisation of unreactive C–H bonds as well as the aziridination of olefines. We report on the synthesis of the trigonal imido iron complexes [Fe(NMes)L2]0,− (L = –N{Dipp}SiMe3); Dipp = 2,6-diisopropyl-phenyl; Mes = (2,4,6-trimethylphenyl) via reaction of mesityl azide (MesN3) with the linear iron precursors [FeL2]0,−. UV-vis-, EPR-, 57Fe Mössbauer spectroscopy, magnetometry, and computational methods suggest for the reduced form an electronic structure as a ferromagnetically coupled iron(ii) imidyl radical, whereas oxidation leads to mixed iron(iii) imidyl and electrophilic iron(ii) nitrene character. Reactivity studies show that both complexes are capable of H atom abstraction from C–H bonds. Further, the reduced form [Fe(NMes)L2]− reacts nucleophilically with CS2 by inserting into the imido iron bond, as well as electrophilically with CO under nitrene transfer. The neutral [Fe(NMes)L2] complex shows enhanced electrophilic behavior as evidenced by nitrene transfer to a phosphine, yet in combination with an overall reduced reactivity. A pair of trigonal imido iron complexes ([Fe(NMes)L2]0,−) in two oxidation states is reported. The anionic complex K{crypt.222}[Fe(NMes)L2] is best described as an iron(ii) imide.![]()
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Affiliation(s)
- Sascha Reith
- Philipps-University Marburg, Department of Chemistry, Hans-Meerwein-Str. 4, D-35037 Marburg, Germany
| | - Serhiy Demeshko
- University of Göttingen, Institute of Inorganic Chemistry, Tammannstr. 4, D-37077 Göttingen, Germany
| | - Beatrice Battistella
- Humboldt-University, Berlin Institute for Chemistry, Brook-Taylor-Str. 2, D-12489 Berlin, Germany
| | - Alexander Reckziegel
- Philipps-University Marburg, Department of Chemistry, Hans-Meerwein-Str. 4, D-35037 Marburg, Germany
| | - Christian Schneider
- Philipps-University Marburg, Department of Chemistry, Hans-Meerwein-Str. 4, D-35037 Marburg, Germany
| | - Andreas Stoy
- Philipps-University Marburg, Department of Chemistry, Hans-Meerwein-Str. 4, D-35037 Marburg, Germany
| | - Crispin Lichtenberg
- Philipps-University Marburg, Department of Chemistry, Hans-Meerwein-Str. 4, D-35037 Marburg, Germany
| | - Franc Meyer
- University of Göttingen, Institute of Inorganic Chemistry, Tammannstr. 4, D-37077 Göttingen, Germany
| | - Dominik Munz
- Saarland University, Inorganic Chemistry: Coordination Chemistry, Campus C4.1, D-66123 Saarbrücken, Germany
- Friedrich-Alexander University Erlangen-Nürnberg, Inorganic Chemistry, Egerlandstr. 1, D-91058 Erlangen, Germany
| | - C. Gunnar Werncke
- Philipps-University Marburg, Department of Chemistry, Hans-Meerwein-Str. 4, D-35037 Marburg, Germany
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Reckziegel A, Kour M, Battistella B, Mebs S, Beuthert K, Berger R, Werncke CG. High-Spin Imido Cobalt Complexes with Imidyl Radical Character*. Angew Chem Int Ed Engl 2021; 60:15376-15380. [PMID: 33977634 PMCID: PMC8362137 DOI: 10.1002/anie.202103841] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/10/2021] [Indexed: 01/21/2023]
Abstract
We report on the synthesis of a variety of trigonal imido cobalt complexes [Co(NAryl)L2 ]- , (L=N(Dipp)SiMe3 ), Dipp=2,6-diisopropylphenyl) with very long Co-NAryl bonds of around 1.75 Å. Their electronic structure was interrogated using a variety of physical and spectroscopic methods such as EPR or X-Ray absorption spectroscopy which leads to their description as highly unusual imidyl cobalt complexes. Computational analyses corroborate these findings and further reveal that the high-spin state is responsible for the imidyl character. Exchange of the Dipp substituent on the imide by the smaller mesityl function (2,4,6-trimethylphenyl) effectuates the unexpected Me3 Si shift from the ancillary ligand set to the imidyl nitrogen, revealing a highly reactive, nucleophilic character of the imidyl unit.
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Affiliation(s)
- Alexander Reckziegel
- Department of ChemistryPhilipps-University MarburgHans-Meerwein-Strasse 435032MarburgGermany
| | - Manjinder Kour
- Department of ChemistryPhilipps-University MarburgHans-Meerwein-Strasse 435032MarburgGermany
| | - Beatrice Battistella
- Institute of ChemistryHumboldt-Universität zu BerlinBrook-Taylor-Strasse 212489BerlinGermany
| | - Stefan Mebs
- Department of PhysicsFreie Universität zu BerlinArnimallee 1414195BerlinGermany
| | - Katrin Beuthert
- Department of ChemistryPhilipps-University MarburgHans-Meerwein-Strasse 435032MarburgGermany
| | - Robert Berger
- Department of ChemistryPhilipps-University MarburgHans-Meerwein-Strasse 435032MarburgGermany
| | - C. Gunnar Werncke
- Department of ChemistryPhilipps-University MarburgHans-Meerwein-Strasse 435032MarburgGermany
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Reckziegel A, Kour M, Battistella B, Mebs S, Beuthert K, Berger R, Werncke CG. High‐Spin‐Imidocobaltkomplexe mit Imidylradikalcharakter**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202103841] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Alexander Reckziegel
- Fachbereich Chemie Philipps-Universität Marburg Hans-Meerwein-Straße 4 35032 Marburg Deutschland
| | - Manjinder Kour
- Fachbereich Chemie Philipps-Universität Marburg Hans-Meerwein-Straße 4 35032 Marburg Deutschland
| | - Beatrice Battistella
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Deutschland
| | - Stefan Mebs
- Fachbereich Physik Freie Universität zu Berlin Arnimallee 14 14195 Berlin Deutschland
| | - Katrin Beuthert
- Fachbereich Chemie Philipps-Universität Marburg Hans-Meerwein-Straße 4 35032 Marburg Deutschland
| | - Robert Berger
- Fachbereich Chemie Philipps-Universität Marburg Hans-Meerwein-Straße 4 35032 Marburg Deutschland
| | - C. Gunnar Werncke
- Fachbereich Chemie Philipps-Universität Marburg Hans-Meerwein-Straße 4 35032 Marburg Deutschland
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Reckziegel A, Pietzonka C, Kraus F, Werncke CG. C-H Bond Activation by an Imido Cobalt(III) and the Resulting Amido Cobalt(II) Complex. Angew Chem Int Ed Engl 2020; 59:8527-8531. [PMID: 32119164 PMCID: PMC7318117 DOI: 10.1002/anie.201914718] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Indexed: 12/31/2022]
Abstract
The 3d-metal mediated nitrene transfer is under intense scrutiny due to its potential as an atom economic and ecologically benign way for the directed amination of (un)functionalised C-H bonds. Here we present the isolation and characterisation of a rare, trigonal imido cobalt(III) complex, which bears a rather long cobalt-imido bond. It can cleanly cleave strong C-H bonds with a bond dissociation energy of up to 92 kcal mol-1 in an intermolecular fashion, unprecedented for imido cobalt complexes. This resulted in the amido cobalt(II) complex [Co(hmds)2 (NHt Bu)]- . Kinetic studies on this reaction revealed an H atom transfer mechanism. Remarkably, the cobalt(II) amide itself is capable of mediating H atom abstraction or stepwise proton/electron transfer depending on the substrate. A cobalt-mediated catalytic application for substrate dehydrogenation using an organo azide is presented.
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Affiliation(s)
- Alexander Reckziegel
- Fachbereich 15/ChemiePhilipps-Universität MarburgHans-Meerwein-Straße 435043MarburgGermany
| | - Clemens Pietzonka
- Fachbereich 15/ChemiePhilipps-Universität MarburgHans-Meerwein-Straße 435043MarburgGermany
| | - Florian Kraus
- Fachbereich 15/ChemiePhilipps-Universität MarburgHans-Meerwein-Straße 435043MarburgGermany
| | - C. Gunnar Werncke
- Fachbereich 15/ChemiePhilipps-Universität MarburgHans-Meerwein-Straße 435043MarburgGermany
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Reckziegel A, Pietzonka C, Kraus F, Werncke CG. C‐H‐Bindungsaktivierung durch einen Imidocobalt(III)‐ und den resultierenden Amidocobalt(II)‐Komplex. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914718] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Alexander Reckziegel
- Fachbereich 15/Chemie Philipps-Universität Marburg Hans-Meerwein-Straße 4 35043 Marburg Deutschland
| | - Clemens Pietzonka
- Fachbereich 15/Chemie Philipps-Universität Marburg Hans-Meerwein-Straße 4 35043 Marburg Deutschland
| | - Florian Kraus
- Fachbereich 15/Chemie Philipps-Universität Marburg Hans-Meerwein-Straße 4 35043 Marburg Deutschland
| | - C. Gunnar Werncke
- Fachbereich 15/Chemie Philipps-Universität Marburg Hans-Meerwein-Straße 4 35043 Marburg Deutschland
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Robertson APM, Reckziegel A, Jones JJ, Rosair GM, Welch AJ. Balancing Steric and Electronic Effects in Carbonyl–Phosphine Molybdacarboranes. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201700492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
| | | | - John J. Jones
- Institute of Chemical Sciences Heriot‐Watt University EH14 4AS Edinburgh UK
| | - Georgina M. Rosair
- Institute of Chemical Sciences Heriot‐Watt University EH14 4AS Edinburgh UK
| | - Alan J. Welch
- Institute of Chemical Sciences Heriot‐Watt University EH14 4AS Edinburgh UK
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Corbellini LG, Pellegrini DCP, Dias RA, Reckziegel A, Todeschini B, Bencke GA. Risk assessment of the introduction of H5N1 highly pathogenic avian influenza as a tool to be applied in prevention strategy plan. Transbound Emerg Dis 2011; 59:106-16. [PMID: 21787379 DOI: 10.1111/j.1865-1682.2011.01246.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Risks of the introduction of highly pathogenic avian influenza (HPAI) H5N1 through migratory birds to the main wintering site for wild birds in southern Brazil and its consequences were assessed. Likelihoods were estimated by a qualitative scale ranging from negligible to high. Northern migrants that breed in Alaska and regularly migrate to South America (primary Charadriiformes) can have contact with birds from affected areas in Asia. The likelihood of the introduction of HPAI H5N1 through migratory birds was found to be very low as it is a probability conditioned to successful transmission in breeding areas and the probabilities of an infected bird migrating and shedding the virus as far as southern Brazil. The probability of wild species becoming exposed to H5N1-infected birds is high as they nest with northern migrants from Alaska, whereas for backyard poultry it is moderate to high depending on proximity to wetlands and the presence of species that could increase the likelihood of contact with wild birds such as domestic duck. The magnitude of the biological and economic consequences of successful transmission to poultry or wild birds would be low to severe depending on the probability of the occurrence of outbreak scenarios described. As a result, the risk estimate is greater than negligible, and HPAI H5N1 prevention strategy in the region should always be carefully considered by the veterinary services in Brazil.
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Affiliation(s)
- L G Corbellini
- EPILAB, Departamento de Medicina Veterinária Preventiva, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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Coracini MD, Bengtsson M, Reckziegel A, Löfqvist J, Francke W, Vilela EF, Eiras AE, Kovaleski A, Witzgall P. Identification of a four-component sex pheromone blend in Bonagota cranaodes (Lepidoptera: Tortricidae). J Econ Entomol 2001; 94:911-914. [PMID: 11561851 DOI: 10.1603/0022-0493-94.4.911] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Analysis of sex pheromone glands of the apple leafroller Bonagota cranaodes Meyrick by gas chromatography coupled with mass spectrometry or electroantennographic detection showed the presence of 14 structurally related acetates and alcohols of the chain length 10-18, including the main pheromone component (E,Z)-3,5-dodecadienyl acetate (E3,Z5-12Ac). Male antennae responded to the main compound, its Z,Z isomer, (E,Z) -3,5-tetradecadienyl acetate (E3,Z5-14Ac), and the monoenes (Z)-5-dodecenyl acetate (Z5-12Ac) and (Z)-9-hexadecenyl acetate (Z9-16Ac). Traps baited with a four-component blend of E3,Z5-12Ac, Z5-12Ac, E3,Z5-14Ac, and Z9-16Ac in a 100:5:5:100 ratio were significantly more attractive than the main compound alone. This improved trap lure is more suitable for monitoring population densities of B. cranaodes, and for detection of the onset of the seasonal flight period. A more complete pheromone blend is of importance also with respect to current attempts to develop mating disruption for control of this major pest of apple in Brazil.
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Affiliation(s)
- M D Coracini
- Department of Crop Science, Swedish University of Agricultural Sciences, Alnarp.
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Abstract
While V gamma 9/V delta 2 cells dominate among peripheral blood gamma delta T cells in healthy adults, the majority of gamma delta T cells in most HIV-1-infected individuals express V delta 1. We asked whether these elevated levels of V delta 1 T cells were due to clonal expansion. Three-color flow cytometry with monoclonal antibodies against V gamma 2/V gamma 3/V gamma 4, V gamma 4 and V gamma 9 was used to investigate V gamma usage in 27 patients with elevated numbers of V delta 1 T cells. While the relative proportion of V gamma 9 cells among gamma delta T cells was significantly reduced in HIV-1+ individuals (10 +/- 11% vs. 80 +/- 17%, p < 0.001), the fraction of gamma delta T cells using V gamma 5 or V gamma 8 was significantly increased (54 +/- 15% vs. 7 +/- 11%, p < 0.001). In 1 patient, 76% of the V delta 1 cells expressed V gamma 2 or V gamma 3, suggesting clonality of the V delta 1 population. In line with this assumption, analysis of the V delta 1-J delta junctional regions by reverse transcription-polymerase chain reaction (RT-PCR) resulted in products of only one junctional length, as demonstrated by electrophoresis on denaturing gels, and 12 out of 16 (75%) in-frame junctional sequences were identical in this patient. In other HIV-1+ patients, RT-PCR resulted in products of several distinct sizes, also indicating a highly restricted repertoire. After sequencing the V delta 1-J delta junctional regions of 3 additional patients, we found repeated but patient-specific in-frame junctions accounting for 10-30% of the sequenced clones. However, limited V delta 1-J delta junctional diversity was also seen in healthy donors. RT-PCR products from 10 healthy individuals resulted in distinct bands on denaturing gels. In 1 of them exhibiting a single prominent band, 10 out of 17 (58%) sequenced junctions were identical. Two other healthy donors displayed 2/14 and 5/18 identical junctional sequences, respectively. Taken together, our results reveal significant alterations of V gamma usage in HIV-1+ patients, while the V delta 1 junctional repertoire is similarly restricted in HIV-1+ and HIV-1- individuals. Therefore, these data argue against an obligatory clonal expansion of V delta 1-expressing cells during HIV-1 infection.
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Affiliation(s)
- T Hinz
- Department of Immunology, Paul Ehrlich Institute, Langen, Germany
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