1
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Jacob HL, Weyer N, Leibold M, Bruhn C, Siemeling U. Ferrocene-Based N-Heterocyclic Silylenes: Monomeric Silanechalcogenones, Silanimines, Silirenes, and Insertion Products with P 4. Chemistry 2024; 30:e202400850. [PMID: 38656583 DOI: 10.1002/chem.202400850] [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: 02/29/2024] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 04/26/2024]
Abstract
The stable ferrocene-based N-heterocyclic silylenes fc[(N{B})2Si] (A; fc=1,1'-ferrocenylene, {B}=(HCNDipp)2B, Dipp=2,6-diisopropylphenyl) and fc[(NDipp)2Si] (B) are compared in a study focussing on their reactivity towards a range of small to moderately sized molecular substrates, viz. P4, S8, Se8, MesN3 (Mes=mesityl), RC≡CH, and RC≡CR (R=Ph, SiMe3). The Dipp-substituted congener B exhibits a more pronounced ambiphilicity and is sterically less congested than its 1,3,2-diazaborolyl-substituted relative A, in line with the higher reactivity of the former. The difference in reactivity is obviously due more to electronic than to steric reasons, as is illustrated by the fact that both A and B react with the comparatively bulky substrate MesN3 under mild conditions to afford the corresponding silanimine fc[(N{B})2Si=NMes] and fc[(NDipp)2Si=NMes], respectively. The heavier ketone analogues fc[(N{B})2Si=E] (E=S, Se, Te) are readily available from A and the corresponding chalcogen. In contrast, the reaction of the more reactive silylene B with elemental sulfur or selenium is unspecific, affording product mixtures. However, fc[(NDipp)2Si=Se] is selectively prepared from B and (Et2N)3PSe; the Te analogue is also accessible, but crystallises as head-to-tail dimer.
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Affiliation(s)
- Hannes L Jacob
- Institute of Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
| | - Nadine Weyer
- Institute of Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
| | - Michael Leibold
- Institute of Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
| | - Clemens Bruhn
- Institute of Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
| | - Ulrich Siemeling
- Institute of Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
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2
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Ryan A, Brookes A, Straiton AJ, Wildsmith T, Lowe JP, Molloy KC, Hill MS, Johnson AL. Heteroallene Insertions into Tin(II) Alkoxide Bonds. Inorg Chem 2024; 63:10967-10979. [PMID: 38832535 PMCID: PMC11190973 DOI: 10.1021/acs.inorgchem.3c04551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 05/21/2024] [Accepted: 05/22/2024] [Indexed: 06/05/2024]
Abstract
A series of iso-carbamate complexes have been synthesized by the reaction of [SnII(OiPr)2] or [SnII(OtBu)2] with either aryl or alkyl isocyanates, ONC-R (R = 2,4,6-trimethylphenyl (Mes), 2,6-diisopropylphenyl (Dipp), isopropyl (iPr), cyclohexyl (Cy) and tert-butyl (tBu)). In the case of aryl isocyanates, mono-insertion occurs to form structurally characterized complexes [Sn{κ2-N,O-R-NC(OiPr)O}(μ-OiPr)]2 (1: R = Mes, 2: R = Dipp) and [Sn{κ2-N,O-R-NC(OtBu)O}(μ-OtBu)]2 (3: R = Mes, 4: R = Dipp). The complicated solution-state chemistry of these species has been explored using 1H DOSY experiments. In contrast, reactions of tin(II) alkoxides with alkyl isocyanates result in the formation of bis-insertion products [Sn{κ2-N,O-R-NC(OiPr)O}2] (5: R = iPr, and 6: R = Cy) and [Sn{κ2-N,O-R-NC(OtBu)O}2] (7: R = iPr, 8: R = Cy), of which complexes 6-8 have also been structurally characterized. 1H NMR studies show that the reaction of tBu-NCO with either [Sn(OiPr)2] or [Sn(OtBu)2] results in a reversible mono-insertion. Variable-temperature 2D 1H-1H exchange spectroscopy (VT-2D-EXSY) was used to determine the rate of exchange between free tBu-NCO and the coordinated tBu-iso-carbamate ligand for the {OiPr} alkoxide complex, as well as the activation energy (Ea = 92.2 ± 0.8 kJ mol-1), enthalpy (ΔH‡ = 89.4 ± 0.8 kJ mol-1), and entropy (ΔS‡ = 12.6 ± 2.9 J mol-1 K-1) for the process [Sn(OiPr)2] + tBu-NCO ↔ [Sn{κ2-N,O-tBu-NC(OiPr)O}(OiPr)]. Attempts to form Sn(II) alkyl carbonates by the insertion of CO2 into either [Sn(OiPr)2] or [Sn(OtBu)2] proved unsuccessful. However, 119Sn{1H} NMR spectroscopy of the reaction of excess CO2 with [Sn(OiPr)2] reveals the presence of a new Sn(II) species, i.e., [(iPrO)Sn(O2COiPr)], VT-2D-EXSY (1H) of which confirms the reversible alkyl carbonate formation (Ea = 70.3 ± 13.0 kJ mol-1; ΔH‡ = 68.0 ± 1.3 kJ mol-1 and ΔS‡ = -8.07 ± 2.8 J mol-1 K-1).
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Affiliation(s)
- Aidan
T. Ryan
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Andrew Brookes
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
- Center
for Sustainable Chemical Technologies, University
of Bath, Bath BA2 7AY, United Kingdom
| | - Andrew J. Straiton
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Thomas Wildsmith
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
- Center
for Sustainable Chemical Technologies, University
of Bath, Bath BA2 7AY, United Kingdom
| | - John P. Lowe
- Material
and Chemical Characterisation Facility (MC), University of Bath, Bath BA2 7AY, United Kingdom
| | - Kieran C. Molloy
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Michael S. Hill
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Andrew L. Johnson
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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3
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Budny-Godlewski K, Piekarski DG, Justyniak I, Leszczyński MK, Nawrocki J, Kubas A, Lewiński J. Uncovering Factors Controlling Reactivity of Metal-TEMPO Reaction Systems in the Solid State and Solution. Chemistry 2024:e202401968. [PMID: 38801170 DOI: 10.1002/chem.202401968] [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: 05/21/2024] [Accepted: 05/22/2024] [Indexed: 05/29/2024]
Abstract
Nitroxides find application in various areas of chemistry, and a more in-depth understanding of factors controlling their reactivity with metal complexes is warranted to promote further developments. Here, we report on the effect of the metal centre Lewis acidity on both the distribution of the O- and N-centered spin density in 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) and turning TEMPO from the O- to N-radical mode scavenger in metal-TEMPO systems. We use Et(Cl)Zn/TEMPO model reaction system with tuneable reactivity in the solid state and solution. Among various products, a unique Lewis acid-base adduct of Cl2Zn with the N-ethylated TEMPO was isolated and structurally characterised, and the so-called solid-state 'slow chemistry' reaction led to a higher yield of the N-alkylated product. The revealed structure-activity/selectivity correlations are exceptional yet are entirely rationalised by the mechanistic underpinning supported by theoretical calculations of studied model systems. This work lays a foundation and mechanistic blueprint for future metal/nitroxide systems exploration.
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Affiliation(s)
- Krzysztof Budny-Godlewski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664, Warsaw, Poland
| | - Dariusz G Piekarski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Iwona Justyniak
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Michał K Leszczyński
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664, Warsaw, Poland
| | - Jan Nawrocki
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Adam Kubas
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Janusz Lewiński
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664, Warsaw, Poland
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4
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Anderson DE, Truong AHN, Hevia E. Dual Basicity and Nucleophilicity of Organosodium Reagents in Benzylic C-H Additions of Toluenes to Diarylethenes and Ketones. Chemistry 2024:e202400492. [PMID: 38651778 DOI: 10.1002/chem.202400492] [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: 02/03/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 04/25/2024]
Abstract
Profiting from the dual high basicity and nucleophilicity of organosodium complexes, here we report the stepwise lateral metalation of a wide range of alkyl arenes (MeAr), mediated by hydrocarbon-soluble NaCH2SiMe3 ⋅ PMDETA (PMDETA=N,N,N',N'',N''-pentamethyldiethylenetriamine), followed by nucleophilic addition to diarylethenes of the newly generated NaCH2Ar ⋅ PMDETA complexes. This method grants access to a range of functionalised hydrocarbons in excellent yields and can be upgraded to catalytic regimes when using trans-stilbene, a 10 mol% of the alkyl sodium base and toluene as a solvent. Extending this approach to aromatic ketones leads to the formation of stilbenes under mild reaction conditions, resulting from the deprotonative coupling of toluenes with ketones. Combining spectroscopic studies with the trapping and characterisation of key reaction intermediates, mechanistic insights have been gained, advancing the understanding of coordination effects in organosodium chemistry, and shedding light on their special reactivity profiles.
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Affiliation(s)
- David E Anderson
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Alex H N Truong
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Eva Hevia
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
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5
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Grabe B, Hiller W. Online coupling of liquid chromatography and two-dimensional diffusion ordered spectroscopy for the analysis of oligostyrenes. J Chromatogr A 2024; 1719:464750. [PMID: 38412606 DOI: 10.1016/j.chroma.2024.464750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 02/01/2024] [Accepted: 02/15/2024] [Indexed: 02/29/2024]
Abstract
The aim of this study was to introduce a powerful coupling of Liquid Adsorption Chromatography (LAC) and Diffusion-Ordered Spectroscopy (DOSY) for comprehensive structure analysis. This new hyphenation approach facilitated the simultaneous separation of a polymer mixture and the determination of molar masses within a single 3D experiment. The online coupling of High-Performance Liquid Chromatography (HPLC) and two-dimensional DOSY-NMR will be called 3D-LAC-NMR-DOSY experiment. Our methodology enabled the chromatographic separation of analytes based on their chemical heterogeneity, and provided accurate molar masses of the analytes through 2D-DOSY. This new method was demonstrated on a polystyrene oligomer mixture. In this case, the oligostyrenes could be separated with LAC according to their tacticity and chain length in protonated acetonitrile as eluent and DOSY measurements provided the molar masses of each oligomer. In order to show the power of the 3D-LAC-NMR-DOSY method, the comparison to 2D-DOSY, 3D-DOSY and LAC-NMR was separately evaluated. Furthermore, the recently published solvent-independent molar mass calibration of diffusion coefficients was also successfully applied in our LAC-DOSY studies for molar mass predictions of the oligomers in acetonitrile. The predicted molar masses were in good agreement with the LAC-DOSY measurements and were verified by calibrations of diffusion coefficients and mass spectrometry. Finally, this pioneering 3D technique offers a powerful new tool for advancing structure analysis and enhancing our understanding of complex systems such as oligostyrenes.
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Affiliation(s)
- Bastian Grabe
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Straße 4a, Dortmund 44227, Germany
| | - Wolf Hiller
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Straße 4a, Dortmund 44227, Germany.
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6
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Dankert F, Hevia E. Synthesis and Modular Reactivity of Low Valent Al/Zn Heterobimetallics Supported by Common Monodentate Amides. Chemistry 2024; 30:e202304336. [PMID: 38189633 DOI: 10.1002/chem.202304336] [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: 01/02/2024] [Revised: 01/05/2024] [Accepted: 01/05/2024] [Indexed: 01/09/2024]
Abstract
Recent advances on low valent main group metal chemistry have shown the excellent potential of heterobimetallic complexes derived from Al(I) to promote cooperative small molecule activation processes. A signature feature of these complexes is the use of bulky chelating ligands which act as spectators providing kinetic stabilization to their highly reactive Al-M bonds. Here we report the synthesis of novel Al/Zn bimetallics prepared by the selective formal insertion of AlCp* into the Zn-N bond of the utility zinc amides ZnR2 (R=HMDS, hexamethyldisilazide; or TMP, 2,2,6,6-tetramethylpiperidide). By systematically assessing the reactivity of the new [(R)(Cp*)AlZn(R)] bimetallics towards carbodiimides, structural and mechanistic insights have been gained on their ability to undergo insertion in their Zn-Al bond. Disclosing a ligand effect, when R=TMP, an isomerization process can be induced giving [(TMP)2AlZn(Cp*)] which displays a special reactivity towards carbodiimides and carbon dioxide involving both its Al-N bonds, leaving its Al-Zn bond untouched.
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Affiliation(s)
- Fabian Dankert
- Department für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestraße 3, Bern, 3012, Switzerland
| | - Eva Hevia
- Department für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestraße 3, Bern, 3012, Switzerland
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7
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Nowag J, Brauser M, Steuernagel L, Wende RC, Schreiner PR, Thiele CM. Quantifying Intermolecular Interactions in Asymmetric Peptide Organocatalysis as a Key toward Understanding Selectivity. J Am Chem Soc 2024; 146:170-180. [PMID: 38117177 DOI: 10.1021/jacs.3c06378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
The kinetic resolution of trans-cyclohexane-1,2-diol with a lipophilic oligopeptide catalyst shows extraordinary selectivities. To improve our understanding of the factors governing selectivity, we quantified the Gibbs free energies of interactions of the peptide with both enantiomers of trans-cyclohexane-1,2-diol using nuclear magnetic resonance (NMR) spectroscopy. For this, we use advanced methods such as transverse relaxation (R2), diffusion measurements, saturation transfer difference (STD), and chemical shift (δ) analysis of peptide-diol mixtures upon varying their composition (NMR titrations). The methods employed give comparable and consistent results. The molecular recognition by the catalyst is approximately 3 kJ mol-1 in favor of the preferentially acetylated (R,R)-enantiomer in the temperature range studied. Interestingly, the difference of 3 kJ mol-1 is also confirmed by results from reaction monitoring of the acylation step under catalytic conditions, indicating that this finding is true regardless of whether the investigation is performed on the acetylated species or on the free catalyst. To arrive at these conclusions, the self-association of both the catalyst and the substrate in toluene was found to play an important role and thus needs to be taken into account in reaction screening.
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Affiliation(s)
- Jens Nowag
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Peter-Grünberg-Straße 16, D-64287 Darmstadt, Germany
| | - Matthias Brauser
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Peter-Grünberg-Straße 16, D-64287 Darmstadt, Germany
| | - Lisa Steuernagel
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Peter-Grünberg-Straße 16, D-64287 Darmstadt, Germany
| | - Raffael C Wende
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
| | - Peter R Schreiner
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
| | - Christina M Thiele
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Peter-Grünberg-Straße 16, D-64287 Darmstadt, Germany
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8
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Townrow OPE, Färber C, Zenneck U, Harder S. Metal Vapour Synthesis of an Organometallic Barium(0) Synthon. Angew Chem Int Ed Engl 2023:e202318428. [PMID: 38078903 DOI: 10.1002/anie.202318428] [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: 12/01/2023] [Indexed: 12/23/2023]
Abstract
A hydrocarbon-soluble barium anthracene complex was prepared by means of metal vapour synthesis. Reaction of 9,10-bis(trimethylsilyl)anthracene (Anth'') with barium vapour gave deep purple Ba(Anth'') which after extraction with diethyl ether crystallised as the cyclic octamer [Ba(Anth'')⋅Et2 O]8 . Dissolution in benzene or toluene led to replacement of the Et2 O ligand with a softer arene ligand and isolation of Ba(Anth'')⋅arene. Diffusion ordered spectroscopy (DOSY NMR ) measurements in benzene-d6 indicate solution species with a molecular weight that equals a trimeric constitution. Natural population analysis (NPA) assigned charges of +1.70 and -1.70 to Ba and Anth'', respectively, relating to highly ionic Ba2+ /Anth''2- bonding. Preliminary reactivity studies with air, Ph2 C=NPh, or H2 show that the complex reacts as a Ba0 synthon by release of neutral Anth''. This soluble molecular Ba0 /BaII redox synthon provides new routes for the syntheses of barium complexes under mild conditions.
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Affiliation(s)
- Oliver P E Townrow
- Inorganic and Organometallic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, 91058, Erlangen, Germany
| | - Christian Färber
- Inorganic and Organometallic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, 91058, Erlangen, Germany
| | - Ulrich Zenneck
- Inorganic and Organometallic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, 91058, Erlangen, Germany
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, 91058, Erlangen, Germany
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9
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Horký F, Franz R, Bruhn C, Pietschnig R. A General Strategy for Increasing the Air Stability of Phosphines Including Primary Phosphines. Chemistry 2023; 29:e202302518. [PMID: 37650772 DOI: 10.1002/chem.202302518] [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: 08/02/2023] [Revised: 08/31/2023] [Accepted: 08/31/2023] [Indexed: 09/01/2023]
Abstract
A general approach for increasing the air-stability of various primary phosphines in the absence of kinetic stabilization is presented that contrasts with previous interpretations, which were limited to specific phosphines. This contribution shows the synthesis of a series of air-stable primary phosphines Fc(CH2 )n PH2 , where n=0,1,2,3; and Fc=ferrocenyl, and their corresponding isolable primary phosphine oxides. It was demonstrated that the ferrocene moiety exerts an antioxidant effect on the primary phosphine group, which is intermolecular, solvent dependent and increases with the electron density on the ferrocene moiety. Furthermore, we demonstrated that the presence of ferrocene in solution also inhibits the oxidation of other secondary and tertiary phosphines in air. Together our findings suggest that quenching of singlet oxygen is the actual reason for the antioxidant effect; this was experimentally confirmed by using other established singlet oxygen quenchers, thus demonstrating a key role of singlet oxygen in the aerobic oxidation of phosphines.
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Affiliation(s)
- Filip Horký
- Institute for Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
| | - Roman Franz
- Institute for Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
| | - Clemens Bruhn
- Institute for Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
| | - Rudolf Pietschnig
- Institute for Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
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10
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Kushvaha SK, Kallenbach P, Rohman SS, Pandey MK, Hendi Z, Rüttger F, Herbst-Irmer R, Stalke D, Parameswaran P, Roesky HW. A Neutral Planar Four-Membered Si 2B 2 2π-Aromatic Ring. J Am Chem Soc 2023; 145:25523-25527. [PMID: 37934173 DOI: 10.1021/jacs.3c09131] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
The synthesis of the first inorganic four-membered neutral 2π-aromatic compound 2 is reported. This unique ring has been synthesized from a simple and straightforward reaction of amidinato-silylene with dichlorophenylborane, followed by the reduction with KC8 in THF. Compound 2 has been fully characterized by single-crystal X-ray diffraction (SC-XRD), NMR spectroscopy, and mass spectrometry. The computational calculations reveal that the Si2B2 ring is a π-delocalized system resulting from the interaction of pπ orbital of B and Si-N σ* orbitals having pseudo π symmetry. Compound 2 is the first known example of a neutral planar inorganic analogue of cyclobutenyl dication.
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Affiliation(s)
- Saroj Kumar Kushvaha
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Paula Kallenbach
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Shahnaz S Rohman
- Department of Chemistry, National Institute of Technology Calicut, Kozhikode 673601, India
| | - Madhusudan K Pandey
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Zohreh Hendi
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Franziska Rüttger
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Regine Herbst-Irmer
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Dietmar Stalke
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Pattiyil Parameswaran
- Department of Chemistry, National Institute of Technology Calicut, Kozhikode 673601, India
| | - Herbert W Roesky
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
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11
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Ivanova S, Adamski P, Köster E, Schramm L, Fröhlich R, Beuerle F. Size Determination of Organic Cages by Diffusion NMR Spectroscopy. Chemistry 2023:e202303318. [PMID: 37966964 DOI: 10.1002/chem.202303318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/15/2023] [Accepted: 11/15/2023] [Indexed: 11/17/2023]
Abstract
Reliable structure elucidation of covalent organic cage compounds remains challenging as routine analysis might leave ambiguities. Diffusion-ordered NMR spectroscopy (DOSY) allows insight into the molecular size and mass of the species present in solution, but a systematic evaluation of the diffusion behavior for cage assemblies is rarely considered. Here we report the synthesis of four series of covalent organic cages based on tribenzotriquinacenes and diboronic acids with varying geometry and exohedral substituents. We provide a guideline for the consistent measurement of diffusion coefficients from 1 H-DOSY NMR spectroscopy, which was utilized to study the diffusion behavior for the whole set of cages and selected examples from the literature. For structurally similar cages, a linear correlation between the solvodynamic volume and the molecular mass allows precise size determination. For more complex systems, multiple parameters, such as window size or rigid exohedral functionalization. further modulate cage diffusion in solution.
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Affiliation(s)
- Svetlana Ivanova
- Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Am Hubland, 97074, Würzburg, Germany
- Julius-Maximilians-Universität Würzburg, Center for Nanosystems Chemistry (CNC), Theodor-Boveri-Weg, 97074, Würzburg, Germany
| | - Paul Adamski
- Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Am Hubland, 97074, Würzburg, Germany
- Julius-Maximilians-Universität Würzburg, Center for Nanosystems Chemistry (CNC), Theodor-Boveri-Weg, 97074, Würzburg, Germany
| | - Eva Köster
- Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Am Hubland, 97074, Würzburg, Germany
- Julius-Maximilians-Universität Würzburg, Center for Nanosystems Chemistry (CNC), Theodor-Boveri-Weg, 97074, Würzburg, Germany
| | - Louis Schramm
- Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Am Hubland, 97074, Würzburg, Germany
- Julius-Maximilians-Universität Würzburg, Center for Nanosystems Chemistry (CNC), Theodor-Boveri-Weg, 97074, Würzburg, Germany
| | - Rebecca Fröhlich
- Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Am Hubland, 97074, Würzburg, Germany
- Julius-Maximilians-Universität Würzburg, Center for Nanosystems Chemistry (CNC), Theodor-Boveri-Weg, 97074, Würzburg, Germany
| | - Florian Beuerle
- Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Am Hubland, 97074, Würzburg, Germany
- Julius-Maximilians-Universität Würzburg, Center for Nanosystems Chemistry (CNC), Theodor-Boveri-Weg, 97074, Würzburg, Germany
- Eberhard Karls Universität Tübingen, Institut für Organische Chemie, Auf der Morgenstelle 18, 72076, Tübingen, Germany
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12
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Schmidt R, Giubertoni G, Caporaletti F, Kolpakov P, Shahidzadeh N, Ariese F, Woutersen S. Raman Diffusion-Ordered Spectroscopy. J Phys Chem A 2023; 127:7638-7645. [PMID: 37656920 PMCID: PMC10510375 DOI: 10.1021/acs.jpca.3c03232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/25/2023] [Indexed: 09/03/2023]
Abstract
The Stokes-Einstein relation, which relates the diffusion coefficient of a molecule to its hydrodynamic radius, is commonly used to determine molecular sizes in chemical analysis methods. Here, we combine the size sensitivity of such diffusion-based methods with the structure sensitivity of Raman spectroscopy by performing Raman diffusion-ordered spectroscopy (Raman-DOSY). The core of the Raman-DOSY setup is a flow cell with a Y-shaped channel containing two inlets: one for the sample solution and one for the pure solvent. The two liquids are injected at the same flow rate, giving rise to two parallel laminar flows in the channel. After the flow stops, the solute molecules diffuse from the solution-filled half of the channel into the solvent-filled half at a rate determined by their hydrodynamic radius. The arrival of the solute molecules in the solvent-filled half of the channel is recorded in a spectrally resolved manner by Raman microspectroscopy. From the time series of Raman spectra, a two-dimensional Raman-DOSY spectrum is obtained, which has the Raman frequency on one axis and the diffusion coefficient (or equivalently, hydrodynamic radius) on the other. In this way, Raman-DOSY spectrally resolves overlapping Raman peaks arising from molecules of different sizes. We demonstrate Raman-DOSY on samples containing up to three compounds and derive the diffusion coefficients of small molecules, proteins, and supramolecules (micelles), illustrating the versatility of Raman-DOSY. Raman-DOSY is label-free and does not require deuterated solvents and can thus be applied to samples and matrices that might be difficult to investigate with other diffusion-based spectroscopy methods.
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Affiliation(s)
- Robert
W. Schmidt
- Vrije
Universiteit Amsterdam, De Boelelaan 1105, 1081HV Amsterdam, The Netherlands
- University
of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - Giulia Giubertoni
- University
of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - Federico Caporaletti
- University
of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
- Université
Libre de Bruxelles, Av.
Franklin Roosevelt 50, 1050 Bruxelles, Belgium
| | - Paul Kolpakov
- University
of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
| | | | - Freek Ariese
- Vrije
Universiteit Amsterdam, De Boelelaan 1105, 1081HV Amsterdam, The Netherlands
| | - Sander Woutersen
- University
of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
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13
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Straiton AJ, Parish JD, Smith JJ, Lowe JP, Johnson AL. Exploration of Solid-State vs Solution-State Structure in Contact Ion Pair Systems: Synthesis, Characterization, and Solution-State Dynamics of Zinc Diphenyl Phosphate, [Zn{O 2P(OPh) 2} 2], Donor-Base-Supported Complexes. Inorg Chem 2023; 62:4770-4785. [PMID: 36916880 PMCID: PMC10052378 DOI: 10.1021/acs.inorgchem.2c03539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
A family of zinc phosphate complexes supported by nitrogen donor-base ligands have been synthesized, and their molecular structures were identified in both the solid (X-ray crystallography) and solution state (DOSY NMR spectroscopy). [Zn{O2P(OPh)2}2]∞ (1), formed from the reaction of Zn[N(SiMe3)2]2 with HO(O)P(OPh)2 coordinates to donor-base ligands, i.e., pyridine (Py), 4-methylpyridine (4-MePy), 2,2-bipyridine (bipy), tetramethylethylenediamine (TMEDA), pentamethyldiethylenetriamine (PMDETA), and 1,3,5-trimethyl-1,3,5-triazacyclohexane (Me3-TAC), to produce polymeric 1D structures, [(Py)2Zn{O2P(OPh)2}2]∞ (2) and [(4-MePy)2Zn{O2P(OPh)2}2]∞ (3), the bimetalic systems, [(Bipy)Zn{O2P(OPh)2}2]2 (4), [(TMEDA)Zn{O2P(OPh)2}2]2 (5), and [(Me3-TAC)Zn{O2P(OPh)2}2]2 (7), as well as a mono-nuclear zinc bis-diphenylphosphate complex, [(PMDETA)Zn{O2P(OPh)2}2] (6). 1H NMR DOSY has been used to calculate averaged molecular weights of the species. Studies are consistent with the disassembly of polymeric 3 into the bimetallic species [(Me-Py)2·Zn2{O2P(OPh)2}4], where the Me-Py ligand is in rapid exchange with free Me-Py in solution. Further 1H DOSY NMR studies of 4 and 5 reveal that dissolution of the complex results in a monomer dimer equilibrium, i.e., [(Bipy)Zn{O2P(OPh)2}2]2 ⇆ 2[(Bipy)Zn{O2P(OPh)2}2] and [(TMEDA)Zn{O2P(OPh)2}2]2 ⇆ 2[(TMEDA)Zn{O2P(OPh)2}2], respectively, in which the equilibria lie toward formation of the monomer. As part of our studies, variable temperature 1H DOSY experiments (223 to 313 K) were performed upon 5 in d8-tol, which allowed us to approximate the enthalpy [ΔH = -43.2 kJ mol-1 (±3.79)], entropy [ΔS = 109 J mol-1 K-1 (±13.9)], and approximate Gibbs free energy [ΔG = 75.6 kJ mol-1 (±5.62) at 293 K)] of monomer-dimer equilibria. While complex 6 is shown to maintain its monomeric solid-state structure, 1H DOSY experiments of 7 at 298 K reveal two separate normalized diffusion coefficients consistent with the presence of the bimetallic species [(TAC)2-xZn2{O2P(OPh)2}4], (x = 1 or 0) and free TAC ligand.
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Affiliation(s)
| | - James D Parish
- Department of Chemistry, University of Bath, Bath BA2 7AY, U.K.,Milton Hill Business & Technology Centre, Infineum UK Ltd, Milton Hill, Abingdon OX13 6BB, U.K
| | - Joshua J Smith
- Milton Hill Business & Technology Centre, Infineum UK Ltd, Milton Hill, Abingdon OX13 6BB, U.K
| | - John P Lowe
- Material and Chemical Characterisation Facility (MC2), University of Bath, Bath BA2 7AY, U.K
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14
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Anderson DE, Tortajada A, Hevia E. Highly Reactive Hydrocarbon Soluble Alkylsodium Reagents for Benzylic Aroylation of Toluenes using Weinreb Amides. Angew Chem Int Ed Engl 2023; 62:e202218498. [PMID: 36636916 DOI: 10.1002/anie.202218498] [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: 12/14/2022] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 01/14/2023]
Abstract
Deaggregating the alkyl sodium NaCH2 SiMe3 with polydentate nitrogen ligands enables the preparation and characterisation of new, hydrocarbon soluble chelated alkylsodium reagents. Equipped with significantly enhanced metalating power over their organolithium counterparts, these systems can promote controlled sodiation of weakly acidic benzylic C-H bonds from a series of toluene derivatives under mild stoichiometric conditions. This has been demonstrated through the benzylic aroylation of toluenes with Weinreb amides, that delivers a wide range of 2-arylacetophenones in good to excellent yields. Success in isolating and determining the structures of key organometallic intermediates has provided useful mechanistic insight into these new sodium-mediated transformations.
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Affiliation(s)
- David E Anderson
- Department für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Andreu Tortajada
- Department für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Eva Hevia
- Department für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
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15
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Terlecki M, Justyniak I, Leszczyński MK, Bernatowicz P, Lewiński J. Factors controlling the structure of alkylzinc amidinates: on the role of N-substituents. Dalton Trans 2023; 52:2712-2721. [PMID: 36748844 DOI: 10.1039/d2dt03722j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Despite various applications of alkylzinc complexes supported by N,N-bidentate ligands in chemistry and materials science, the corresponding organozinc amidinates still represent an insufficiently explored area. To gain a more in-depth understanding of factors controlling the structure and stability of alkylzinc amidinates, we selected benzamidinate and N,N'-diphenylformamidinate ligands as model N,N'-unsubstituted and N,N'-diaryl substituted ligands, respectively, to systematically modify the secondary coordination sphere of the Zn center. A series of new alkylzinc amidinates has been synthesized and their molecular structures identified in both the solid state (single-crystal X-ray crystallography) and solution (NMR and FTIR spectroscopy). The results indicate that [RZnL]x-type amidinate moieties are essentially unstable and tend to undergo Schlenk equilibria-mediated ligand scrambling leading to more thermodynamically stable non-stoichiometric [R2Zn3L4]- and [R3Zn4L5]-type complexes. This process is significantly influenced by the secondary coordination sphere noncovalent interactions as well as the steric hindrance provided by both zinc-bounded alkyl groups and the N-substituents.
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Affiliation(s)
- Michał Terlecki
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
| | - Iwona Justyniak
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Michał K Leszczyński
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland. .,Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Piotr Bernatowicz
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Janusz Lewiński
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland. .,Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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16
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Uhlmann C, Feuerstein TJ, Gamer MT, Roesky PW. Coinage Metal Bis(amidinate) Complexes as Building Blocks for Self-Assembled One-Dimensional Coordination Polymers. Chemistry 2023; 29:e202300289. [PMID: 36762591 DOI: 10.1002/chem.202300289] [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: 01/27/2023] [Revised: 02/09/2023] [Accepted: 02/09/2023] [Indexed: 02/11/2023]
Abstract
The pyridyl functionalized amidinate [{PyC≡CC(NDipp)2 }Li(thf)2 ]n was used to synthesize a series of bis-amidinate complexes [{PyC≡CC(NDipp)2 }2 M2 ] (M=Cu, Ag, Au) with fully supported metallophilic interactions. These metalloligands were then used as building blocks for the synthesis of one-dimensional heterobimetallic coordination polymers using Zn(hfac)2 (hfac=hexaflouroacetylacetonate) for self-assembly. Interestingly, the three coordination polymers [{PyC≡CC(NDipp)2 }2 M2 ][Zn(hfac)2 ] (M=Cu, Ag, Au), exhibit a zig zag shape in the solid state. To achieve linear coordination geometry other connectors such as M'(acac) (M'=Ni, Co) (acac=acetylacetonate) were investigated. The thus obtained compounds [{PyC≡CC(NDipp)2 }2 Cu2 ][M'(acac)2 ] (M'=Ni, Co) are indeed linear heterobimetallic coordination polymers featuring a metalloligand backbone with fully supported metallophilic interactions.
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Affiliation(s)
- Cedric Uhlmann
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131, Karlsruhe, Germany
| | - Thomas J Feuerstein
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131, Karlsruhe, Germany
| | - Michael T Gamer
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131, Karlsruhe, Germany
| | - Peter W Roesky
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131, Karlsruhe, Germany
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17
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Sengupta S, Schüler P, Liebing P, Westerhausen M. Synthesis of Sterically Encumbered Alkaline-Earth Metal Amides Applying the In Situ Grignard Reagent Formation. Chemistry 2023; 29:e202300035. [PMID: 36734181 DOI: 10.1002/chem.202300035] [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: 01/05/2023] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/04/2023]
Abstract
Magnesium and calcium are too inert to deprotonate amines directly. For the synthesis of bulky amides alternative strategies are required and in the past, N-bound trialkylsilyl groups have been used to ease metalation reactions. The in situ Grignard reagent formation in stirred suspensions of magnesium or calcium with hydryl halide and imine in THF allows the synthesis of a plethora of amides with bulky silyl-free substituents. Ball milling protocols partially favor competitive side reactions such as aza-pinacol coupling reactions. Calcium is the advantageous choice for the in situ Grignard reagent formation and subsequent addition onto the imines yielding bulky calcium bis(amides) whereas the stronger reducing heavier alkaline-earth metals strontium and barium are less selective and hence, the aza-pinacol coupling reaction becomes competitive. Exemplary, the solid-state molecular structures of [(Et2 O)Mg(N(Ph)(CHPh2 )2 ] and [(Et2 O)2 Ca(N(Ph)(CHPh2 )2 ] have been determined.
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Affiliation(s)
- Simon Sengupta
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Philipp Schüler
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Phil Liebing
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Matthias Westerhausen
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
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18
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Straiton A, McMullin CL, Kociok- Köhn G, Lyall CL, Parish JD, Johnson AL. Lithium, Tin(II), and Zinc Amino-Boryloxy Complexes: Synthesis and Characterization. Inorg Chem 2023; 62:2576-2591. [PMID: 36708353 PMCID: PMC9930121 DOI: 10.1021/acs.inorgchem.2c03108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Analogous to the ubiquitous alkoxide ligand, metal boroxide and boryloxy complexes are an underexplored class of hard anionic O- ligand. A new series of amine-stabilized Li, Sn(II), and Zn boryloxy complexes, comprising electron-rich tetrahedral boron centers have been synthesized and characterized. All complexes have been characterized by one-dimensional (1D), two-dimensional (2D), and DOSY NMR, which are consistent with the solid-state structures unambiguously determined via single-crystal X-ray diffraction. Electron-rich μ2- (Sn and Zn) and μ3- (Li) boryloxy binding modes are observed. Compounds 6-9 are the first complexes of this class, with the chelating bis- and tris-phenol ligands providing a scaffold that can be easily functionalized and provides access to the boronic acid pro-ligand, hence allowing facile direct synthesis of the resulting compounds. Computational quantum chemical studies suggest a significant enhancement of the π-donor ability of the amine-stabilized boryloxy ligand because of electron donation from the amine functionality into the p-orbital of the boron atom.
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Affiliation(s)
- Andrew
J. Straiton
- Department
of Chemistry, University of Bath, Claverton Down BA2 7AY, U.K.
| | - Claire L. McMullin
- Department
of Chemistry, University of Bath, Claverton Down BA2 7AY, U.K.
| | - Gabriele Kociok- Köhn
- Material
and Chemical Characterisation Facility, University of Bath, Claverton
Down BA2 7AY, U.K.
| | - Catherine L. Lyall
- Material
and Chemical Characterisation Facility, University of Bath, Claverton
Down BA2 7AY, U.K.
| | - James D. Parish
- Infineum
UK Ltd., Milton Hill Business and Technology Centre, Abingdon OX13 6BB, Oxfordshire, U.K.
| | - Andrew L. Johnson
- Department
of Chemistry, University of Bath, Claverton Down BA2 7AY, U.K.,
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19
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Hédouin M, Barthelemy AL, Vanthuyne N, Besrour H, Maddaluno J, Magnier E, Oulyadi H. NMR and DFT Studies with a Doubly Labelled 15 N/ 6 Li S-Trifluoromethyl Sulfoximine Reveal Why a Directed ortho-Lithiation Requires an Excess of n-BuLi. Angew Chem Int Ed Engl 2023; 62:e202214106. [PMID: 36377763 PMCID: PMC10108270 DOI: 10.1002/anie.202214106] [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: 09/24/2022] [Indexed: 11/16/2022]
Abstract
This work shows why it is imperious to use an excess of butyllithium for a directed ortho-lithiation of a trifluoromethyl sulfoximine. The analysis of mixtures of n-BuLi and sulfoximine 1 in THF-d8 using {1 H, 6 Li, 13 C, 15 N, 19 F} NMR experiments at low temperatures reveal that a first deprotonation occurs that leads to dimeric and tetrameric N-lithiated sulfoximine (93 : 7). Using an excess n-BuLi (5 equivalents), the second deprotonation on the ortho-position of the aromatic occurs. Six species were observed and characterized on the way. It includes three aggregates involving a sulfoximine: i) a [dilithiated sulfoximine/(n-BuLi)] dimer solvated by four molecules of THF (Agg2, 39 %); ii) a [dilithiated sulfoximine/(n-BuLi)3 ] tetramer solvated by six molecules of THF (Agg3, 39 %); iii) a [dilithiated sulfoximine/(n-BuOLi)3 ] tetramer solvated by four molecules of THF (Agg1, 22 %). A DFT study afforded optimized solvated structures for all these aggregates, fully consistent with the NMR data.
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Affiliation(s)
- Matthieu Hédouin
- Laboratoire COBRA (UMR 6014 & FR 3038), Normandie Université, UNIROUEN, INSA Rouen, CNRS Rue Tesniere, 76821, Mont Saint Aignan, France
| | - Anne-Laure Barthelemy
- Institut Lavoisier de Versailles (UMR 8180), Université Paris-Saclay, UVSQ, CNRS, 45 avenue des Etats-Unis, 78035, Versailles, France
| | - Nicolas Vanthuyne
- iSm2, UMR 7313, Aix Marseille Univ, CNRS, Centrale Marseille, AMUtech, 13288, Marseille, France
| | - Hend Besrour
- Laboratoire COBRA (UMR 6014 & FR 3038), Normandie Université, UNIROUEN, INSA Rouen, CNRS Rue Tesniere, 76821, Mont Saint Aignan, France
| | - Jacques Maddaluno
- Laboratoire COBRA (UMR 6014 & FR 3038), Normandie Université, UNIROUEN, INSA Rouen, CNRS Rue Tesniere, 76821, Mont Saint Aignan, France
| | - Emmanuel Magnier
- Institut Lavoisier de Versailles (UMR 8180), Université Paris-Saclay, UVSQ, CNRS, 45 avenue des Etats-Unis, 78035, Versailles, France
| | - Hassan Oulyadi
- Laboratoire COBRA (UMR 6014 & FR 3038), Normandie Université, UNIROUEN, INSA Rouen, CNRS Rue Tesniere, 76821, Mont Saint Aignan, France
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20
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Giubertoni G, Rombouts G, Caporaletti F, Deblais A, van Diest R, Reek JNH, Bonn D, Woutersen S. Infrared Diffusion-Ordered Spectroscopy Reveals Molecular Size and Structure. Angew Chem Int Ed Engl 2023; 62:e202213424. [PMID: 36259515 PMCID: PMC10107201 DOI: 10.1002/anie.202213424] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Indexed: 11/07/2022]
Abstract
Inspired by ideas from NMR, we have developed Infrared Diffusion-Ordered Spectroscopy (IR-DOSY), which simultaneously characterizes molecular structure and size. We rely on the fact that the diffusion coefficient of a molecule is determined by its size through the Stokes-Einstein relation, and achieve sensitivity to the diffusion coefficient by creating a concentration gradient and tracking its equilibration in an IR-frequency resolved manner. Analogous to NMR-DOSY, a two-dimensional IR-DOSY spectrum has IR frequency along one axis and diffusion coefficient (or equivalently, size) along the other, so the chemical structure and the size of a compound are characterized simultaneously. In an IR-DOSY spectrum of a mixture, molecules with different sizes are nicely separated into distinct sets of IR peaks. Extending this idea to higher dimensions, we also perform 3D-IR-DOSY, in which we combine the conformation sensitivity of femtosecond multi-dimensional IR spectroscopy with size sensitivity.
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Affiliation(s)
- Giulia Giubertoni
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands
| | - Gijs Rombouts
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands
| | - Federico Caporaletti
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands.,Institute of Physics, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands
| | - Antoine Deblais
- Institute of Physics, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands
| | - Rianne van Diest
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands
| | - Joost N H Reek
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands
| | - Daniel Bonn
- Institute of Physics, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands
| | - Sander Woutersen
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands
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21
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Structural Characterization of the 1-Metallo-2-t-Butyl-1,2-Dihydropyridyl Rubidium and Caesium Complexes. Polyhedron 2023. [DOI: 10.1016/j.poly.2023.116302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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22
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Lui NM, MacMillan SN, Collum DB. Lithiated Oppolzer Enolates: Solution Structures, Mechanism of Alkylation, and Origin of Stereoselectivity. J Am Chem Soc 2022; 144:23379-23395. [PMID: 36534055 PMCID: PMC10071589 DOI: 10.1021/jacs.2c09341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Camphorsultam-based lithium enolates referred to colloquially as Oppolzer enolates are examined spectroscopically, crystallographically, kinetically, and computationally to ascertain the mechanism of alkylation and the origin of the stereoselectivity. Solvent- and substrate-dependent structures include tetramers for alkyl-substituted enolates in toluene, unsymmetric dimers for aryl-substituted enolates in toluene, substrate-independent symmetric dimers in THF and THF/toluene mixtures, HMPA-bridged trisolvated dimers at low HMPA concentrations, and disolvated monomers for the aryl-substituted enolates at elevated HMPA concentrations. Extensive analyses of the stereochemistry of aggregation are included. Rate studies for reaction with allyl bromide implicate an HMPA-solvated ion pair with a +Li(HMPA)4 counterion. Dependencies on toluene and THF are attributed to exclusively secondary-shell (medium) effects. Aided by density functional theory (DFT) computations, a stereochemical model is presented in which neither chelates nor the lithium gegenion serves roles. The stereoselectivity stems from the chirality within the sultam ring and not the camphor skeletal core.
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Affiliation(s)
- Nathan M Lui
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University Ithaca, New York 14853-1301, United States
| | - Samantha N MacMillan
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University Ithaca, New York 14853-1301, United States
| | - David B Collum
- Department of Chemistry and Chemical Biology Baker Laboratory, Cornell University Ithaca, New York 14853-1301, United States
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23
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Martínez-Manjarres A, Quevedo R. Intermolecular hydrogen bonding effects on the reaction of dianisidine, bisphenol A (BPA) and formaldehyde. RESULTS IN CHEMISTRY 2022. [DOI: 10.1016/j.rechem.2022.100723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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24
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Schüler P, Sengupta S, Koch A, Görls H, Krieck S, Westerhausen M. In situ Grignard Metalation Method, Part II: Scope of the One-Pot Synthesis of Organocalcium Compounds. Chemistry 2022; 28:e202201897. [PMID: 35912418 PMCID: PMC9804548 DOI: 10.1002/chem.202201897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Indexed: 01/05/2023]
Abstract
The in situ Grignard Metalation Method (iGMM) is a straightforward one-pot strategy to synthesize alkaline-earth metal amides in multi-gram scale with high yields via addition of bromoethane to an ethereal suspension of a primary or secondary amine and magnesium (Part I) or calcium (Part II). This method is highly advantageous because no activation of calcium is required prior to the reaction. Contrary to the magnesium-based iGMM, there are some limitations, the most conspicuous one is the large influence of steric factors. The preparation of Ca(hmds)2 succeeds smoothly within a few hours with excellent yields opening the opportunity to prepare large amounts of this reagent. Side reactions and transfer of the iGMM to substituted anilines and N-heterocycles as well as other H-acidic substrates such as cyclopentadienes are studied. Bulky amidines cannot be converted directly to calcium amidinates via the iGMM but stoichiometric calciation with Ca(hmds)2 enables their preparation.
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Affiliation(s)
- Philipp Schüler
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Simon Sengupta
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Alexander Koch
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Helmar Görls
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Sven Krieck
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Matthias Westerhausen
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
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Davison N, Quirk JA, Wills C, Dixon C, Waddell PG, Dawson JA, Lu E. Elucidating Solution-State Coordination Modes of Multidentate Neutral Amine Ligands with Group-1 Metal Cations: Variable-Temperature NMR Studies. Inorg Chem 2022; 61:15204-15212. [PMID: 36109881 PMCID: PMC9516690 DOI: 10.1021/acs.inorgchem.2c02457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Multidentate neutral amine ligands play vital roles in
coordination
chemistry and catalysis. In particular, these ligands are used to
tune the reactivity of Group-1 metal reagents, such as organolithium
reagents. Most, if not all, of these Group-1 metal reagent-mediated
reactions occur in solution. However, the solution-state coordination
behaviors of these ligands with Group-1 metal cations are poorly understood,
compared to the plethora of solid-state structural studies based on
single-crystal X-ray diffraction (SCXRD) studies. In this work, we
comprehensively mapped out the coordination modes with Group-1 metal
cations for three multidentate neutral amine ligands: tridentate 1,4,7-trimethyl-1,4,7-triazacyclononane
(Me3TACN), tetradentate tris[2-(dimethylamino)ethyl]amine
(Me6Tren), and hexadentate N,N′,N″-tris-(2-N-diethylaminoethyl)-1,4,7-triaza-cyclononane
(DETAN). The macrocycles in the Me3TACN and DETAN are identified
as the rigid structural directing motif, with the sidearms of DETAN
providing flexible “on-demand” coordination sites. In
comparison, the Me6Tren ligand features more robust coordination,
with the sidearms less likely to undergo the decoordinating–coordinating
equilibrium. This work will provide a guidance for coordination chemists
in applying these three ligands, in particular, the new DETAN ligand
to design metal complexes which suit their purposes. Combining variable-temperature nuclear
magnetic resonance
(VT NMR) and DFT calculations, this work elucidates the solution-state
coordination modes of three multidentate neutral amine ligands with
Group-1 metal cations. Our studies prove that two ligand-design building
blocks, that is, N-macrocycle (TACN) and N-sidearms, act as structure-dictating
and hemilabile coordinating sites, respectively. The concept could
be utilized in designing new catalytic systems, which anchor the metal
center on the macrocycle, while the sidearms serve as “on-demand”
protective coordination sites.
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Affiliation(s)
- Nathan Davison
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - James A. Quirk
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Corinne Wills
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Casey Dixon
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Paul G. Waddell
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - James A. Dawson
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Erli Lu
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
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Sengupta S, Schüler P, Görls H, Liebing P, Krieck S, Westerhausen M. In Situ Grignard Metalation Method for the Synthesis of Hauser Bases. Chemistry 2022; 28:e202201359. [PMID: 35686618 PMCID: PMC9546396 DOI: 10.1002/chem.202201359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Indexed: 12/03/2022]
Abstract
The in situ Grignard Metalation Method (iGMM) is a straightforward one‐pot procedure to quickly produce multigram amounts of Hauser bases R2N‐MgBr which are valuable and vastly used metalation reagents and novel electrolytes for magnesium batteries. During addition of bromoethane to a suspension of Mg metal and secondary amine at room temperature in an ethereal solvent, a smooth reaction yields R2N‐MgBr under evolution of ethane within a few hours. A Schlenk equilibrium is operative, interconverting the Hauser bases into their solvated homoleptic congeners Mg(NR2)2 and MgBr2 depending on the solvent. Scope and preconditions are studied, and side reactions limiting the yield have been investigated. DOSY NMR experiments and X‐ray crystal structures of characteristic examples clarify aggregation in solution and the solid state.
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Affiliation(s)
- Simon Sengupta
- Institute of Inorganic and Analytical Chemistry Friedrich Schiller University Jena Humboldtstraße 8 07743 Jena Germany
| | - Philipp Schüler
- Institute of Inorganic and Analytical Chemistry Friedrich Schiller University Jena Humboldtstraße 8 07743 Jena Germany
| | - Helmar Görls
- Institute of Inorganic and Analytical Chemistry Friedrich Schiller University Jena Humboldtstraße 8 07743 Jena Germany
| | - Phil Liebing
- Institute of Inorganic and Analytical Chemistry Friedrich Schiller University Jena Humboldtstraße 8 07743 Jena Germany
| | - Sven Krieck
- Institute of Inorganic and Analytical Chemistry Friedrich Schiller University Jena Humboldtstraße 8 07743 Jena Germany
| | - Matthias Westerhausen
- Institute of Inorganic and Analytical Chemistry Friedrich Schiller University Jena Humboldtstraße 8 07743 Jena Germany
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27
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Kutateladze DA, Wagen CC, Jacobsen EN. Chloride-Mediated Alkene Activation Drives Enantioselective Thiourea and Hydrogen Chloride Co-Catalyzed Prins Cyclizations. J Am Chem Soc 2022; 144:15812-15824. [PMID: 35994741 PMCID: PMC9437134 DOI: 10.1021/jacs.2c06688] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The mechanism of chiral hydrogen-bond donor (HBD) and hydrogen chloride (HCl) co-catalyzed Prins cyclizations was analyzed through a combination of experimental and computational methods and revealed to involve an unexpected and previously unrecognized mode of alkene activation. Kinetic and spectroscopic studies support the participation of a catalytically active HCl·HBD complex that displays reduced Brønsted acidity relative to HCl alone. Nevertheless, rate acceleration relative to the HCl-catalyzed background reaction as well as high levels of enantioselectivity are achieved. This inverse Brønsted correlation is ascribed to chloride-mediated substrate activation in the rate-limiting and enantiodetermining cyclization transition state. Density functional theory (DFT) calculations, distortion-interaction analysis, and quasiclassical dynamics simulations support a stepwise mechanism in which rate acceleration and enantioselectivity are achieved through the precise positioning of the chloride anion within the active site of the chiral thiourea to enhance the nucleophilicity of the alkene and provide transition-state stabilization through local electric field effects. This mode of selective catalysis through anion positioning likely has general implications for the design of enantioselective Brønsted acid-catalyzed reactions involving π-nucleophiles.
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Affiliation(s)
| | | | - Eric N. Jacobsen
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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28
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N-O Ligand Supported Stannylenes: Preparation, Crystal, and Molecular Structures. INORGANICS 2022. [DOI: 10.3390/inorganics10090129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A new series of tin(II) complexes (1, 2, 4, and 5) were successfully synthesized by employing hydroxy functionalized pyridine ligands, specifically 2-hydroxypyridine (hpH), 8-hydroxyquinoline (hqH), and 10-hydroxybenzo[h]quinoline (hbqH) as stabilizing ligands. Complexes [Sn(μ-κ2ON-OC5H4N)(N{SiMe3}2)]2 (1) and [Sn4(μ-κ2ON-OC5H4N)6(κ1O-OC5H4N)2] (2) are the first structurally characterized examples of tin(II) oxypyridinato complexes exhibiting {Sn2(OCN)2} heterocyclic cores. As part of our study, 1H DOSY NMR experiments were undertaken using an external calibration curve (ECC) approach, with temperature-independent normalized diffusion coefficients, to determine the nature of oligomerisation of 2 in solution. An experimentally determined diffusion coefficient (298 K) of 6.87 × 10−10 m2 s−1 corresponds to a hydrodynamic radius of Ca. 4.95 Å. This is consistent with the observation of an averaged hydrodynamic radii and equilibria between dimeric [Sn{hp}2]2 and tetrameric [Sn{hp}2]4 species at 298 K. Testing this hypothesis, 1H DOSY NMR experiments were undertaken at regular intervals between 298 K–348 K and show a clear change in the calculated hydrodynamic radii form 4.95 Å (298 K) to 4.35 Å (348 K) consistent with a tetramer ⇄ dimer equilibria which lies towards the dimeric species at higher temperatures. Using these data, thermodynamic parameters for the equilibrium (ΔH° = 70.4 (±9.22) kJ mol−1, ΔS° = 259 (±29.5) J K−1 mol−1 and ΔG°298 = −6.97 (±12.7) kJ mol−1) were calculated. In the course of our studies, the Sn(II) oxo cluster, [Sn6(m3-O)6(OR)4:{Sn(II)(OR)2}2] (3) (R = C5H4N) was serendipitously isolated, and its molecular structure was determined by single-crystal X-ray diffraction analysis. However, attempts to characterise the complex by multinuclear NMR spectroscopy were thwarted by solubility issues, and attempts to synthesise 3 on a larger scale were unsuccessful. In contrast to the oligomeric structures observed for 1 and 2, single-crystal X-ray diffraction studies unambiguously establish the monomeric 4-coordinate solid-state structures of [Sn(κ2ON-OC9H6N)2)] (4) and [Sn(κ2ON-OC13H8N)2)] (5).
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29
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Tang B, Chong K, Massefski W, Evans R. Quantitative Interpretation of Protein Diffusion Coefficients in Mixed Protiated-Deuteriated Aqueous Solvents. J Phys Chem B 2022; 126:5887-5895. [PMID: 35917500 PMCID: PMC9376945 DOI: 10.1021/acs.jpcb.2c03554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Diffusion-ordered nuclear magnetic resonance (NMR) spectroscopy
is widely used for the analysis of mixtures, dispersing the signals
of different species in a two-dimensional spectrum according to their
diffusion coefficients. However, interpretation of these diffusion
coefficients is typically purely qualitative, for example, to deduce
which species are bigger or smaller. In studies of proteins in solution,
important questions concern the molecular weight of the proteins,
the presence or absence of aggregation, and the degree of folding.
The Stokes–Einstein Gierer–Wirtz estimation (SEGWE)
method has been previously developed to simplify the complex relationship
between diffusion coefficient and molecular mass, allowing the prediction
of a species’ diffusion coefficient in a pure solvent based
on its molecular weight. Here, we show that SEGWE can be extended
to successfully predict both peptide and protein diffusion coefficients
in mixed protiated–deuteriated water samples and, hence, distinguish
effectively between globular and disordered proteins.
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Affiliation(s)
- Bridget Tang
- Aston Institute of Materials Research, Aston University, Birmingham B4 7ET, U.K
| | - Katie Chong
- Energy and Bioproducts Research Institute (EBRI), Aston University, Birmingham B4 7ET, U.K
| | - Walter Massefski
- Department of Chemistry Instrumentation Facility, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Robert Evans
- Aston Institute of Materials Research, Aston University, Birmingham B4 7ET, U.K
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30
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Bole LJ, Tortajada A, Hevia E. Enhancing Metalating Efficiency of the Sodium Amide NaTMP in Arene Borylation Applications. Angew Chem Int Ed Engl 2022; 61:e202204262. [PMID: 35420221 PMCID: PMC9323492 DOI: 10.1002/anie.202204262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Indexed: 12/12/2022]
Affiliation(s)
- Leonie J. Bole
- Departement für Chemie, Biochemie und Pharmazie Universität Bern Freiestrasse 3 3012 Bern Switzerland
| | - Andreu Tortajada
- Departement für Chemie, Biochemie und Pharmazie Universität Bern Freiestrasse 3 3012 Bern Switzerland
| | - Eva Hevia
- Departement für Chemie, Biochemie und Pharmazie Universität Bern Freiestrasse 3 3012 Bern Switzerland
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31
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Schüler P, Krieck S, Görls H, Liebing P, Westerhausen M. Sterically shielded primary anilides of the alkaline-earth metals of the type (thf) nAe(NH-Ar*) 2 (Ae = Mg, Ca, Sr, and Ba; Ar* = bulky aryl). Dalton Trans 2022; 51:8461-8471. [PMID: 35603695 DOI: 10.1039/d2dt01121b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Metalation of 2,4,6-triphenylphenylamine (H2N-C6H2-2,4,6-Ph3, 1a) and 4-methyl-2,6-bis(diphenylmethyl)aniline (2,6-bis(diphenylmethyl)-p-toluidine, H2N-C6H2-4-Me-2,6-(CHPh2)2, 2a) with dibutylmagnesium and Ae[N(SiMe3)2]2 with a stoichiometric 1 : 2 ratio in THF at room temperature yields the corresponding primary anilides [(thf)nAe{N(H)-C6H2-2,4,6-Ph3}2] (Ae/n = Mg/2 (1b), Ca/2 (1c), Sr/3 (1d), and Ba/3 (1e)) and [(thf)nAe{N(H)-C6H2-4-Me-2,6-(CHPh2)2}2] (Ae/n = Mg/2 (2b), Ca/3 (2c) and Sr/2 (2d)), respectively. The 1 : 1 reaction of Mg(n/sBu)2 and MgPh2 with 2a leads to the formation of heteroleptic [(thf)2Mg(R){N(H)-C6H2-4-Me-2,6-(CHPh2)2}] (R = n/sBu (2bBu), Ph (2bPh)). At 50 °C, the strontium complex 2d liberates one equivalent of 2avia intramolecular deprotonation of the triarylmethyl functionality yielding dinuclear [(thf)2Sr{N(H)-C6H2-4-Me-2-(CPh2)-6-(CHPh2)2}]2 (2d'). The barium compound is significantly more reactive and regardless of applied stoichiometry the isotypic barium congener [(thf)2Ba{N(H)-C6H2-4-Me-2-(CPh2)-6-(CHPh2)2}]2 (2e') forms. The molecular structures of 1c, 2d, 2d', and 2e' are stabilized by metal-phenyl π-interactions.
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Affiliation(s)
- Philipp Schüler
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, D-07743 Jena, Germany.
| | - Sven Krieck
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, D-07743 Jena, Germany.
| | - Helmar Görls
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, D-07743 Jena, Germany.
| | - Phil Liebing
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, D-07743 Jena, Germany.
| | - Matthias Westerhausen
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, D-07743 Jena, Germany.
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32
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Asymmetrically Substituted Phospholes as Ligands for Coinage Metal Complexes. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27113368. [PMID: 35684306 PMCID: PMC9182544 DOI: 10.3390/molecules27113368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/13/2022] [Accepted: 05/19/2022] [Indexed: 11/29/2022]
Abstract
A series of coinage metal complexes asymmetrically substituted 2,5-diaryl phosphole ligands is reported. Structure, identity, and purity of all obtained complexes were corroborated with state-of-the-art techniques (multinuclear NMR, mass spectrometry, elemental analysis, X-ray diffraction) in solution and solid state. All complexes obtained feature luminescence in solution as well as in the solid state. Additionally, DOSY-MW NMR estimation experiments were performed to achieve information about the aggregation behavior of the complexes in solution allowing a direct comparison with their structures observed in the solid state.
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33
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Bole L, Tortajada A, Hevia E. Enhancing Metalating Efficiency of the Sodium Amide NaTMP in Arene Borylation Applications. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202204262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Leonie Bole
- Universitat Bern Department of Chemistry, Biochemistry and Pharmaceutical Sciences SWITZERLAND
| | - Andreu Tortajada
- Universitat Bern Department of Chemistry, Biochemistry and Pharmaceutical Sciences SWITZERLAND
| | - Eva Hevia
- Universitat Bern Department of Chemistry and Biochemistry Freiestrasse 3 3012 Bern SWITZERLAND
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34
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Koehne I, Pietschnig R. Synthesis of Geminal Bis‐ and Tetrakisphosphonate Ester Derivatives and Their Coordination Behavior Towards Ca(II) Ions. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202200194] [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)
- Ingo Koehne
- Universität Kassel: Universitat Kassel Institut für Chemie GERMANY
| | - Rudolf Pietschnig
- Universität Kassel Institut für Chemie Heinrich-Plett-Strasse 40 34132 Kassel GERMANY
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35
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Ben-Tal Y, Boaler PJ, Dale HJA, Dooley RE, Fohn NA, Gao Y, García-Domínguez A, Grant KM, Hall AMR, Hayes HLD, Kucharski MM, Wei R, Lloyd-Jones GC. Mechanistic analysis by NMR spectroscopy: A users guide. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 129:28-106. [PMID: 35292133 DOI: 10.1016/j.pnmrs.2022.01.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
A 'principles and practice' tutorial-style review of the application of solution-phase NMR in the analysis of the mechanisms of homogeneous organic and organometallic reactions and processes. This review of 345 references summarises why solution-phase NMR spectroscopy is uniquely effective in such studies, allowing non-destructive, quantitative analysis of a wide range of nuclei common to organic and organometallic reactions, providing exquisite structural detail, and using instrumentation that is routinely available in most chemistry research facilities. The review is in two parts. The first comprises an introduction to general techniques and equipment, and guidelines for their selection and application. Topics include practical aspects of the reaction itself, reaction monitoring techniques, NMR data acquisition and processing, analysis of temporal concentration data, NMR titrations, DOSY, and the use of isotopes. The second part comprises a series of 15 Case Studies, each selected to illustrate specific techniques and approaches discussed in the first part, including in situ NMR (1/2H, 10/11B, 13C, 15N, 19F, 29Si, 31P), kinetic and equilibrium isotope effects, isotope entrainment, isotope shifts, isotopes at natural abundance, scalar coupling, kinetic analysis (VTNA, RPKA, simulation, steady-state), stopped-flow NMR, flow NMR, rapid injection NMR, pure shift NMR, dynamic nuclear polarisation, 1H/19F DOSY NMR, and in situ illumination NMR.
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Affiliation(s)
- Yael Ben-Tal
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Patrick J Boaler
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Harvey J A Dale
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Ruth E Dooley
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom; Evotec (UK) Ltd, 114 Innovation Drive, Milton Park, Abingdon, Oxfordshire OX14 4RZ, United Kingdom
| | - Nicole A Fohn
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Yuan Gao
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Andrés García-Domínguez
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Katie M Grant
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Andrew M R Hall
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Hannah L D Hayes
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Maciej M Kucharski
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Ran Wei
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Guy C Lloyd-Jones
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom.
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36
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Lüert D, Kreyenschmidt AK, Legendre CM, Herbst-Irmer R, Stalke D. A Sodium Sodate as Precursor for Lanthanide Bis(4- R-benzoxazol-2-yl)methanide Single-Molecule Magnets. Inorg Chem 2022; 61:5234-5244. [PMID: 35316598 DOI: 10.1021/acs.inorgchem.1c03714] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
From the sodium sodate precursor [(Na(thf)6][Na{(4-Me-NCOC6H3)2CH}2] (1) three isostructural dinuclear lanthanide complexes [(μ-Cl)LnIII{(4-MeNCOC6H3)2CH}2]2 with Ln = Gd (2), Dy (3), and Er (4) based on the N,N'-chelating monoanionic bis(4-methylbenzoxazol-2-yl)methanide ligand (titled "Mebox") were synthesized and characterized by X-ray diffraction and magnetic measurements. The sodium precursor 1 was analyzed via X-ray diffraction and diffusion-ordered NMR spectroscopy experiments (DOSY-NMR) in order to investigate its aggregation in solution and the solid state. The sodium analog [(thf)3Na(NCOC6H4)2CH] (1') based on the bis(benzoxazol-2-yl)-methanide ligand (titled "box") was prepared and analyzed for comparison reasons. From the lanthanide derivatives 2-4, the DyIII complex 3 displays slow relaxation of magnetization at zero field, with a relaxation barrier of U = 315.7 cm-1. The coupling strength between the two lanthanide centers was estimated with the GdIII equivalent 2, giving a weak antiferromagnetic coupling of J = -0.035 cm-1.
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Affiliation(s)
- Daniel Lüert
- Department of Inorganic Chemistry, University of Goettingen, Tammannstrasse 4, 37077 Goettingen, Germany
| | - Anne-Kathrin Kreyenschmidt
- Department of Inorganic Chemistry, University of Goettingen, Tammannstrasse 4, 37077 Goettingen, Germany
| | - Christina M Legendre
- Department of Inorganic Chemistry, University of Goettingen, Tammannstrasse 4, 37077 Goettingen, Germany
| | - Regine Herbst-Irmer
- Department of Inorganic Chemistry, University of Goettingen, Tammannstrasse 4, 37077 Goettingen, Germany
| | - Dietmar Stalke
- Department of Inorganic Chemistry, University of Goettingen, Tammannstrasse 4, 37077 Goettingen, Germany
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37
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Suitability of Carbazolyl Hauser and Turbo‐Hauser Bases as Magnesium‐Based Electrolytes. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202200149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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38
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Pflock S, Langer F, Reil M, Strinitz L, Lorenz R, Hübner EG, Burzlaff N. p-Block metal complexes with bis(pyrazol-1-yl)acetato ligands. Dalton Trans 2022; 51:3902-3912. [PMID: 35168247 DOI: 10.1039/d1dt04040e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The hetereoscorpionate ligands bis(pyrazol-1-yl)acetic acid (Hbpza) and bis(3,5-dimethylpyrazol-1-yl)acetic acid (Hbdmpza) are reacted with [Sn(OAc)2] or [Sn(acac)2] to yield the corresponding Sn(II) complexes. A single crystal X-ray determination for the in solution monomeric complex [Sn(bpza)2] (1a) revealed a dinuclear molecular structure [Sn2(bpza)4] (1b), with κ3-N,N,O-coordinated bpza ligands at each of the Sn(II) and two bpza ligands μ-bridging between the Sn(II) centres. The molecular structure of [Sn(bdmpza)2] (2) exhibits a homoleptic bisligand complex with both ligands displaced by the free electron pair, which is proven by DFT calculations. Oxidation of complex 2 in an attempt to synthesize a homoleptic Sn(IV) complex leads to the formation of [Sn(bdmpza)F3] (3). In addition, homoleptic bisligand gallium complexes [Ga(bdmpza)2][ClO4] (4) and [Ga(bpza)2][GaCl4] (5) were prepared and characterized by 71Ga NMR and IR spectroscopy as well as by X-ray crystallography.
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Affiliation(s)
- Stephan Pflock
- Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany.
| | - Frauke Langer
- Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany.
| | - Michaela Reil
- Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany.
| | - Lisa Strinitz
- Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany.
| | - Rebecca Lorenz
- Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany.
| | - Eike G Hübner
- Institute of Organic Chemistry, Clausthal University of Technology Leibnizstraße 6, 38678 Clausthal-Zellerfeld, Germany
| | - Nicolai Burzlaff
- Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany.
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39
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Zanata DDM, Felisberti MI. Thermo- and pH-responsive POEGMA-b-PDMAEMA-b-POEGMA triblock copolymers. Eur Polym J 2022. [DOI: 10.1016/j.eurpolymj.2022.111069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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40
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Davison N, Zhou K, Waddell PG, Wills C, Dixon C, Hu SX, Lu E. Versatile Coordination Modes of Multidentate Neutral Amine Ligands with Group 1 Metal Cations. Inorg Chem 2022; 61:3674-3682. [PMID: 35148099 PMCID: PMC9097481 DOI: 10.1021/acs.inorgchem.1c03786] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Indexed: 12/30/2022]
Abstract
This work comprehensively investigated the coordination chemistry of a hexa-dentate neutral amine ligand, namely, N,N',N"-tris-(2-N-diethylaminoethyl)-1,4,7-triaza-cyclononane (DETAN), with group-1 metal cations (Li+, Na+, K+, Rb+, Cs+). Versatile coordination modes were observed, from four-coordinate trigonal pyramidal to six-coordinate trigonal prismatic, depending on the metal ionic radii and metal's substituent. For comparison, the coordination chemistry of a tetra-dentate tris-[2-(dimethylamino)ethyl]amine (Me6Tren) ligand was also studied. This work defines the available coordination modes of two multidentate amine ligands (DETAN and Me6Tren), guiding future applications of these ligands for pursuing highly reactive and elusive s-block and rare-earth metal complexes.
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Affiliation(s)
- Nathan Davison
- Chemistry-School
of Natural and Environmental Sciences, Newcastle
University, Newcastle
upon Tyne, United Kingdom, NE1 7RU
| | - Ke Zhou
- College
of Chemistry and Environmental Science & Shaanxi Key Laboratory
of Catalysis & Institute of Theoretical and Computational Chemistry, Shaanxi University of Technology. Hanzhong 723000, Shaanxi Province, China
| | - Paul G. Waddell
- Chemistry-School
of Natural and Environmental Sciences, Newcastle
University, Newcastle
upon Tyne, United Kingdom, NE1 7RU
| | - Corinne Wills
- Chemistry-School
of Natural and Environmental Sciences, Newcastle
University, Newcastle
upon Tyne, United Kingdom, NE1 7RU
| | - Casey Dixon
- Chemistry-School
of Natural and Environmental Sciences, Newcastle
University, Newcastle
upon Tyne, United Kingdom, NE1 7RU
| | - Shu-Xian Hu
- Beijing
Computational Science Research Center, Beijing 100193, China
| | - Erli Lu
- Chemistry-School
of Natural and Environmental Sciences, Newcastle
University, Newcastle
upon Tyne, United Kingdom, NE1 7RU
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41
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Marcos-Ayuso G, Lledós A, Casares JA. Copper(I) activation of C-X bonds: bimolecular vs. unimolecular reaction mechanism. Chem Commun (Camb) 2022; 58:2718-2721. [PMID: 35113089 DOI: 10.1039/d1cc07027d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Experimental kinetic studies and DFT calculations show that the oxidative addition of aryl halides (Ar-X) to complexes [Cu(NHC)R] follow different paths depending on the nature of X. For X = Br a concerted addition leads to cis-[Cu(NHC)XRAr] from which the usual C-C coupled product Ar-R eliminates. However, for X = I trans-[Cu(NHC)IRAr] is formed instead, leading to the elimination of R-I in a metathesis reaction. This behaviour is accounted for by a change in the reaction mechanism for Ar-I, which involves two molecules of copper(I) complex, the second one stabilising the incipient iodide formed in the C-I breaking (oxidative addition) and C-I forming (reductive elimination) processes.
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Affiliation(s)
- Guillermo Marcos-Ayuso
- IU CINQUIMA/Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, 47011-Valladolid, Spain.
| | - Agustí Lledós
- Departament de Química, Edifici C.n, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Catalonia, Spain.
| | - Juan A Casares
- IU CINQUIMA/Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, 47011-Valladolid, Spain.
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42
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Westerhausen M, Mandel MJ, Müller C, Görls H, Krieck S. Metalation of Aryl‐bis(3‐alkyl‐5‐methylpyrazol‐1‐yl)methane (Alkyl = Me, Ad; Aryl = Ph, C6H4‐2‐OH) with NaN(SiMe3)2, KN(SiMe3)2, and Ca{N(SiMe3)2}2. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202101051] [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)
| | - Miles J. Mandel
- Friedrich-Schiller-Universität Jena: Friedrich-Schiller-Universitat Jena Institute of Inorganic and Analytical Chemistry GERMANY
| | - Christoph Müller
- Friedrich Schiller University Jena: Friedrich-Schiller-Universitat Jena Institute of Inorganic and Analytical Chemistry GERMANY
| | - Helmar Görls
- Friedrich Schiller University Jena: Friedrich-Schiller-Universitat Jena Institute of Inorganic and Analytical Chemistry GERMANY
| | - Sven Krieck
- Friedrich-Schiller-Universität Jena: Friedrich-Schiller-Universitat Jena Institute of Inorganic and Analytical Chemistry GERMANY
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43
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Schäfer F, Mix A, Cati N, Lamm JH, Neumann B, Stammler G, Mitzel NW. Host guest chemistry of a bidentate silyl-triflate bis-Lewis-acid – complex complexation behaviour unravelled by diffusion NMR spectroscopy. Dalton Trans 2022; 51:7164-7173. [DOI: 10.1039/d2dt00583b] [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 bidentate silicon-based Lewis acid, bis(dimethyl-(trifluoromethylsulfonyl)silylethyl)dimethylsilane, Me2Si[(CH2)2SiMe2-OTf]2, was prepared by a two-step synthesis starting from dimethyldivinylsilane by hydrosilylation with dimethylchlorosilane and subsequent Lewis acidity enhancement of the terminal silicon atoms...
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44
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Schüler P, Görls H, Krieck S, Westerhausen M. One-Step Synthesis and Schlenk-Type Equilibrium of Cyclopentadienylmagnesium Bromides. Chemistry 2021; 27:15508-15515. [PMID: 34468050 PMCID: PMC8597043 DOI: 10.1002/chem.202102636] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Indexed: 12/23/2022]
Abstract
In the in situ Grignard metalation method (iGMM), the addition of bromoethane to a suspension of magnesium turnings and cyclopentadienes [C5 H6 (HCp), C5 H5 -Si(iPr)3 (HCpTIPS )] in diethyl ether smoothly yields heteroleptic [(Et2 O)Mg(CpR )(μ-Br)]2 (CpR =Cp (1), CpTIPS (2)). The Schlenk equilibrium of 2 in toluene leads to ligand exchange and formation of homoleptic [Mg(CpR )2 ] (3) and [(Et2 O)MgBr(μ-Br)]2 (4). Interfering solvation and aggregation as well as ligand redistribution equilibria hamper a quantitative elucidation of thermodynamic data for the Schlenk equilibrium of 2 in toluene. In ethereal solvents, mononuclear species [(Et2 O)2 Mg(CpTIPS )Br] (2'), [(Et2 O)n Mg(CpTIPS )2 ] (3'), and [(Et2 O)2 MgBr2 ] (4') coexist. Larger coordination numbers can be realized with cyclic ethers like tetrahydropyran allowing crystallization of [(thp)4 MgBr2 ] (5). The interpretation of the temperature-dependency of the Schlenk equilibrium constant in diethyl ether gives a reaction enthalpy ΔH and reaction entropy ΔS of -11.5 kJ mol-1 and 60 J mol-1 , respectively.
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Affiliation(s)
- Philipp Schüler
- Institute of Inorganic and Analytical ChemistryFriedrich Schiller University JenaHumboldtstraße 807743JenaGermany
| | - Helmar Görls
- Institute of Inorganic and Analytical ChemistryFriedrich Schiller University JenaHumboldtstraße 807743JenaGermany
| | - Sven Krieck
- Institute of Inorganic and Analytical ChemistryFriedrich Schiller University JenaHumboldtstraße 807743JenaGermany
| | - Matthias Westerhausen
- Institute of Inorganic and Analytical ChemistryFriedrich Schiller University JenaHumboldtstraße 807743JenaGermany
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45
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Aldrich KE, Livshits MY, Stromberg LR, Janicke MT, Nhu Lam M, Stein B, Wagner GL, Abergel RJ, Mukundan H, Kozimor SA, Lilley LM. Th IV-Desferrioxamine: characterization of a fluorescent bacterial probe. Dalton Trans 2021; 50:15310-15320. [PMID: 34636377 DOI: 10.1039/d1dt02177j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Diversifying our ability to guard against emerging pathogenic threats is essential for keeping pace with global health challenges, including those presented by drug-resistant bacteria. Some modern diagnostic and therapeutic innovations to address this challenge focus on targeting methods that exploit bacterial nutrient sequestration pathways, such as the desferrioxamine (DFO) siderophore used by Staphylococcus aureus (S. aureus) to sequester FeIII. Building on recent studies that have shown DFO to be a versatile vehicle for chemical delivery, we show proof-of-principle that the FeIII sequestration pathway can be used to deliver a potential radiotherapeutic. Our approach replaces the FeIII nutrient sequestered by H4DFO+ with ThIV and made use of a common fluorophore, FITC, which we covalently bonded to DFO to provide a combinatorial probe for simultaneous chelation paired with imaging and spectroscopy, H3DFO_FITC. Combining insight provided from FITC-based imaging with characterization by NMR spectroscopy, we demonstrated that the fluorescent DFO_FITC conjugate retained the ThIV chelation properties of native H4DFO+. Fluorescence microscopy with both [Th(DFO_FITC)] and [Fe(DFO_FITC)] complexes showed similar uptake by S. aureus and increased intercellular accumulation as compared to the FITC and unchelated H3DFO_FITC controls. Collectively, these results demonstrate the potential for the newly developed H3DFO_FITC conjugate to be used as a targeting vector and bacterial imaging probe for S. aureus. The results presented within provide a framework to expand H4DFO+ and H3DFO_FITC to relevant radiotherapeutics (like 227Th).
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Affiliation(s)
| | | | | | | | - Mila Nhu Lam
- Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA.
| | - Benjamin Stein
- Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA.
| | | | - Rebecca J Abergel
- Department of Chemistry, University of California, Berkeley, California, 94720, USA
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46
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Zovko C, Schoo C, Feuerstein TJ, Münzfeld L, Knöfel ND, Lebedkin S, Kappes MM, Roesky PW. Alkali Metal Complexes of a Bis(diphenylphosphino)methane Functionalized Amidinate Ligand: Synthesis and Luminescence. Chemistry 2021; 27:15119-15126. [PMID: 34427374 PMCID: PMC8596514 DOI: 10.1002/chem.202102243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Indexed: 12/22/2022]
Abstract
A novel bis(diphenylphosphino)methane (DPPM) functionalized amidine ligand (DPPM-C(N-Dipp)2 H) (Dipp=2,6-diisopropylphenyl) was synthesized. Subsequent deprotonation with suitable alkali metal bases resulted in the corresponding complexes [M{DPPM-C(N-Dipp)2 }(Ln )] (M=Li, Na, K, Rb, Cs; L=thf, Et2 O). The alkali metal complexes form monomeric species in the solid state, exhibiting intramolecular metal-π-interactions. In addition, a caesium derivative [Cs{PPh2 CH2 -C(N-Dipp)2 }]6 was obtained by cleavage of a diphenylphosphino moiety, forming an unusual six-membered ring structure in the solid state. All complexes were fully characterized by single crystal X-ray diffraction, NMR spectroscopy, IR spectroscopy as well as elemental analysis. Furthermore, the photoluminescent properties of the complexes were thoroughly investigated, revealing differences in emission with regards to the respective alkali metal. Interestingly, the hexanuclear [Cs{PPh2 CH2 -C(N-Dipp)2 }]6 metallocycle exhibits a blue emission in the solid state, which is significantly red-shifted at low temperatures. The bifunctional design of the ligand, featuring orthogonal donor atoms (N vs. P) and a high steric demand, is highly promising for the construction of advanced metal and main group complexes.
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Affiliation(s)
- Christina Zovko
- Institute of Inorganic ChemistryKarlsruhe Institute of Technology (KIT)Engesserstraße 1576131KarlsruheGermany
| | - Christoph Schoo
- Institute of Inorganic ChemistryKarlsruhe Institute of Technology (KIT)Engesserstraße 1576131KarlsruheGermany
| | - Thomas J. Feuerstein
- Institute of Inorganic ChemistryKarlsruhe Institute of Technology (KIT)Engesserstraße 1576131KarlsruheGermany
| | - Luca Münzfeld
- Institute of Inorganic ChemistryKarlsruhe Institute of Technology (KIT)Engesserstraße 1576131KarlsruheGermany
| | - Nicolai D. Knöfel
- Institute of Inorganic ChemistryKarlsruhe Institute of Technology (KIT)Engesserstraße 1576131KarlsruheGermany
| | - Sergei Lebedkin
- Institute of NanotechnologyKarlsruhe Institute of Technology (KIT)Hermann-von-Helmholtz-Platz 176344Eggenstein-LeopoldshafenGermany
| | - Manfred M. Kappes
- Institute of NanotechnologyKarlsruhe Institute of Technology (KIT)Hermann-von-Helmholtz-Platz 176344Eggenstein-LeopoldshafenGermany
- Institute of Physical ChemistryKarlsruhe Institute of Technology (KIT)Fritz-Haber-Weg. 276131KarlsruheGermany
| | - Peter W. Roesky
- Institute of Inorganic ChemistryKarlsruhe Institute of Technology (KIT)Engesserstraße 1576131KarlsruheGermany
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47
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García-Romero Á, Martín-Álvarez JM, Colebatch AL, Plajer AJ, Miguel D, Álvarez CM, García-Rodríguez R. Synthesis of tris(3-pyridyl)aluminate ligand and its unexpected stability against hydrolysis: revealing cooperativity effects in heterobimetallic pyridyl aluminates. Dalton Trans 2021; 50:13059-13065. [PMID: 34581366 DOI: 10.1039/d1dt02351a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We report the elusive metallic anion [EtAl(3-py)3]- (3-py = 3-pyridyl) (1), the first member of the anionic tris(3-pyridyl) family. Unexpectedly, the lithium complex 1Li shows substantial protic stability against water and alcohols, unlike related tris(2-pyridyl)aluminate analogues. This stability appears to be related to the inability of the [EtAl(3-py)3]- anion to chelate Li+, which precludes a decomposition pathway involving Li/Al cooperativity.
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Affiliation(s)
- Álvaro García-Romero
- GIR MIOMeT-IU Cinquima-Química Inorgánica Facultad de Ciencias, Universidad de Valladolid; Campus Miguel Delibes, 47011 Valladolid, Spain.
| | - Jose M Martín-Álvarez
- GIR MIOMeT-IU Cinquima-Química Inorgánica Facultad de Ciencias, Universidad de Valladolid; Campus Miguel Delibes, 47011 Valladolid, Spain.
| | - Annie L Colebatch
- Chemistry Department. Cambridge University, Lensfield Road, Cambridge CB2 1EW, UK.,Research School of Chemistry. Australian National University, Canberra, ACT, 2601, Australia
| | - Alex J Plajer
- Chemical Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Daniel Miguel
- GIR MIOMeT-IU Cinquima-Química Inorgánica Facultad de Ciencias, Universidad de Valladolid; Campus Miguel Delibes, 47011 Valladolid, Spain.
| | - Celedonio M Álvarez
- GIR MIOMeT-IU Cinquima-Química Inorgánica Facultad de Ciencias, Universidad de Valladolid; Campus Miguel Delibes, 47011 Valladolid, Spain.
| | - Raúl García-Rodríguez
- GIR MIOMeT-IU Cinquima-Química Inorgánica Facultad de Ciencias, Universidad de Valladolid; Campus Miguel Delibes, 47011 Valladolid, Spain.
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48
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Touchet S, Yeardley C, O'Hara CT, Gros PC. Critical Ligand and Salt Effects in Organomagnesiate‐Promoted 3,3‐Disubstituted Phthalides Synthesis from 2‐Iodobenzoate Derivatives. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | - Callum Yeardley
- WestCHEM University of Strathclyde 295 Cathedral Street Glasgow G1 1XL UK
| | - Charles T. O'Hara
- WestCHEM University of Strathclyde 295 Cathedral Street Glasgow G1 1XL UK
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49
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Kleks G, Holland DC, Porter J, Carroll AR. Natural products dereplication by diffusion ordered NMR spectroscopy (DOSY). Chem Sci 2021; 12:10930-10943. [PMID: 34476071 PMCID: PMC8372548 DOI: 10.1039/d1sc02940a] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/15/2021] [Indexed: 11/21/2022] Open
Abstract
Diffusion-ordered NMR spectroscopy (DOSY) can be used to analyze mixtures of compounds since resonances deriving from different compounds are distinguished by their diffusion coefficients (D). Previously, DOSY has mostly been used for organometallic and polymer analysis, we have now applied DOSY to investigate diffusion coefficients of structurally diverse organic compounds such as natural products (NP). The experimental Ds derived from 55 diverse NPs has allowed us to establish a power law relationship between D and molecular weight (MW) and therefore predict MW from experimental D. We have shown that D is also affected by factors such as hydrogen bonding, molar density and molecular shape of the compound and we have generated new models that incorporate experimentally derived variables for these factors so that more accurate predictions of MW can be calculated from experimental D. The recognition that multiple physicochemical properties affect D has allowed us to generate a polynomial equation based on multiple linear regression analysis of eight calculated physicochemical properties from 63 compounds to accurately correlate predicted D with experimental D for any known organic compound. This equation has been used to calculate predicted D for 217 043 compounds present in a publicly available natural product database (DEREP-NP) and to dereplicate known NPs in a mixture based on matching of experimental D and structural features derived from NMR analysis with predicted D and calculated structural features in the database. These models have been validated by the dereplication of a mixture of two known sesquiterpenes obtained from Tasmannia xerophila and the identification of new alkaloids from the bryozoan Amathia lamourouxi. These new methodologies allow the MW of compounds in mixtures to be predicted without the need for MS analysis, the dereplication of known compounds and identification of new compounds based solely on parameters derived by DOSY NMR. We report accurate DOSY NMR based molecular weight and diffusion coefficient prediction tools. These tools can be used to dereplicate known natural products from databases using structurally rich NMR data as a surrogate for mass spectrometric data.![]()
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Affiliation(s)
- Guy Kleks
- School of Environment and Science, Griffith University Gold Coast QLD 4222 Australia .,Griffith Institute for Drug Discovery, Griffith University Brisbane QLD 4111 Australia
| | - Darren C Holland
- School of Environment and Science, Griffith University Gold Coast QLD 4222 Australia .,Griffith Institute for Drug Discovery, Griffith University Brisbane QLD 4111 Australia
| | - Joshua Porter
- School of Environment and Science, Griffith University Gold Coast QLD 4222 Australia .,Griffith Institute for Drug Discovery, Griffith University Brisbane QLD 4111 Australia
| | - Anthony R Carroll
- School of Environment and Science, Griffith University Gold Coast QLD 4222 Australia .,Griffith Institute for Drug Discovery, Griffith University Brisbane QLD 4111 Australia
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50
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Tanase T, Nakamae K, Miyano H, Ura Y, Kitagawa Y, Yada S, Yoshimura T, Nakajima T. Fine Tunable, Redox Active Octapalladium Chains Supported by Linear Tetraphosphines, Leading to Dynamically 1D Self-Assembled Coordination Polymers. Chemistry 2021; 27:12078-12103. [PMID: 34155699 DOI: 10.1002/chem.202101715] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Indexed: 12/16/2022]
Abstract
A series of the octapalladium chains supported by meso-Ph2 PCH2 P(Ph)CH2 P(Ph)CH2 PPh2 (meso-dpmppm) ligands, [Pd8 (meso-dpmppm)4 (L)2 ](BF4 )4 (L=none (1), solvents: CH3 CN (2 a), dmf (2 b), dmso (2 c), RN≡C: R=Xyl (3 a), Mes (3 b), Dip (3 c), t Bu (3 d), Cy (3 e), CH3 (CH2 )7 (3 f), CH3 (CH2 )11 (3 g), CH3 (CH2 )17 (3 h)) and [Pd8 (meso-dpmppm)4 (X)2 ](BF4 )2 (X=Cl (4 a), N3 (4 b), CN (4 c), SCN (4 d)), were synthesized by using 2 a as a stable good precursor, and characterized by spectroscopic (IR, 1 H and 31 P NMR, UV-vis-NIR, ESI-MS) measurements and X-ray crystallographic analyses (for 1, 2 a, b, 3 a, b, e, f, 4 a-d). On the basis of DFT calculations on the X-ray determined structure of 2 b ([2b-Pd8 ]4+ ) and the optimized models [Pd8 (meso-Ph2 PCH2 P(H)CH2 P(H)CH2 PH2 )4 (CH3 CN)2 ]4+ ([Pd8 Ph8 ]4+ ) and [Pd8 (meso-H2 PCH2 P(H)CH2 P(H)CH2 PH2 )4 (CH3 CN)2 ]4+ ([Pd8 H8 ]4+ ), with and without empirically calculating dispersion force stabilization energy (B3LYP-D3, B3LYP), the formation energy between the two Pd4 fragments is assumed to involve mainly noncovalent interactions (ca. -70 kcal/mol) with four sets of interligand C-H/π interactions and Pd⋅⋅⋅Pd metallophilic one, while electron shared covalent interactions are almost canceled out within the Pd8 chain. All the compounds isolated are stable in solution and exhibit characteristic absorption at ∼900 nm, which is assignable to a spin allowed HOMO to LUMO transition, and shows temperature dependent intensity change with variable absorption coefficients presumably due to coupling with some thermal vibrations. The structures and electronic states of the Pd8 chains are found finely tunable by varying the terminal capping ligands. In particular, theoretical calculations elucidated that the HOMO-LUMO energy gap is systematically related to the central Pd-Pd distance (2.7319(6)-2.7575(6) Å) by two ways with neutral ligands L (1, 2, 3) and with anionic ligands X (4), which are reflected on the NIR absorption energy of 867-954 nm. The isocyanide terminated Pd8 complexes (3) further reacted with excess of RNC (6 eq) to afford the Pd4 complexes, [Pd4 (meso-dpmppm)2 (RNC)2 ](BF4 )2 (13), and the cyclic voltammograms of 2 a (L=CH3 CN), 3, and 13 (R=Xyl, Mes, t Bu, Cy) demonstrated wide range redox behaviors from 2{Pd4 }4+ to 2{Pd4 }0 through 2{Pd4 }2+ ↔{Pd8 }4+ , {Pd8 }3+ , and {Pd8 }2+ strings. The oxidized complexes, [Pd4 (meso-dpmppm)2 (RNC)3 ](BF4 )4 (16), were characterized by X-ray analyses, and the two-electron reduced chain of [Pd8 (meso-dpmppm)4 ](BF4 )2 (7) was analyzed by spectroscopic and electrochemical techniques and DFT calculations. Reactions of 2 a with 1 equiv. of aromatic linear bisisocyanide (BI) in CH2 Cl2 deposited insoluble coordination polymers, {[Pd8 (meso-dpmppm)4 (BI)](BF4 )4 }n (5), and interestingly, they were soluble in acetonitrile, 31 P{1 H} and 1 H DOSY NMR spectra as well as SAXS curves suggesting that the coordination polymers may exist in acetonitrile as dynamically 1D self-assembled coordination polymers comprising ca. 50 units of the Pd8 rod averaged within the timescale.
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Affiliation(s)
- Tomoaki Tanase
- Department of Chemistry, Faculty of Science, Nara Women's University, Kitauoya-nishi-machi, 630-8506, Nara, Japan
| | - Kanako Nakamae
- Department of Chemistry, Faculty of Science, Nara Women's University, Kitauoya-nishi-machi, 630-8506, Nara, Japan
| | - Haruka Miyano
- Department of Chemistry, Faculty of Science, Nara Women's University, Kitauoya-nishi-machi, 630-8506, Nara, Japan
| | - Yasuyuki Ura
- Department of Chemistry, Faculty of Science, Nara Women's University, Kitauoya-nishi-machi, 630-8506, Nara, Japan
| | - Yasutaka Kitagawa
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, 560-8531, Toyonaka, Osaka, Japan
| | - Shiho Yada
- Department of Chemistry, Faculty of Science, Nara Women's University, Kitauoya-nishi-machi, 630-8506, Nara, Japan
| | - Tomokazu Yoshimura
- Department of Chemistry, Faculty of Science, Nara Women's University, Kitauoya-nishi-machi, 630-8506, Nara, Japan
| | - Takayuki Nakajima
- Department of Chemistry, Faculty of Science, Nara Women's University, Kitauoya-nishi-machi, 630-8506, Nara, Japan
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