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Sancho I, Navarro M, Montilla M, Salvador P, Santamaría C, Luis JM, Hernán-Gómez A. Ti(III) Catalysts for CO 2/Epoxide Copolymerization at Unusual Ambient Pressure Conditions. Inorg Chem 2023; 62:14873-14887. [PMID: 37651747 PMCID: PMC10521022 DOI: 10.1021/acs.inorgchem.3c01249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Indexed: 09/02/2023]
Abstract
Titanium compounds in low oxidation states are highly reducing species and hence powerful tools for the functionalization of small molecules. However, their potential has not yet been fully realized because harnessing these highly reactive complexes for productive reactivity is generally challenging. Advancing this field, herein we provide a detailed route for the formation of titanium(III) orthophenylendiamido (PDA) species using [LiBHEt3] as a reducing agent. Initially, the corresponding lithium PDA compounds [Li2(ArPDA)(thf)3] (Ar = 2,4,6-trimethylphenyl (MesPDA), 2,6-diisopropylphenyl (iPrPDA)) are combined with [TiCl4(thf)2] to form the heterobimetallic complexes [{TiCl(ArPDA)}(μ-ArPDA){Li(thf)n}] (n = 1, Ar = iPr 3 and n = 2, Ar = Mes 4). Compound 4 evolves to species [Ti(MesPDA)2] (6) via thermal treatment. In contrast, the transformation of 3 into [Ti(iPrPDA)2] (5) only occurs in the presence of [LiNMe2], through a lithium-assisted process, as revealed by density functional theory (DFT). Finally, the Ti(IV) compounds 3-6 react with [LiBHEt3] to give rise to the Ti(III) species [Li(thf)4][Ti(ArPDA)2] (Ar = iPr 8, Mes 9). These low-valent compounds in combination with [PPN]Cl (PPN = bis(triphenylphosphine)iminium) are proved to be highly selective catalysts for the copolymerization of CO2 and cyclohexene epoxide. Reactions occur at 1 bar pressure with activity/selectivity levels similar to Salen-Cr(III) compounds.
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Affiliation(s)
- Ignacio Sancho
- Departamento
de Química Orgánica y Química Inorgánica,
Instituto de Investigación Química “Andrés
M. del Río” (IQAR), Universidad
de Alcalá, Campus
Universitario, E-28805 Alcalá de Henares, Madrid, Spain
| | - Marta Navarro
- Departamento
de Química Orgánica y Química Inorgánica,
Instituto de Investigación Química “Andrés
M. del Río” (IQAR), Universidad
de Alcalá, Campus
Universitario, E-28805 Alcalá de Henares, Madrid, Spain
| | - Marc Montilla
- Institute
of Computational Chemistry and Catalysis and Department of Chemistry, University of Girona, Campus de Montilivi, 17003 Girona, Catalonia, Spain
| | - Pedro Salvador
- Institute
of Computational Chemistry and Catalysis and Department of Chemistry, University of Girona, Campus de Montilivi, 17003 Girona, Catalonia, Spain
| | - Cristina Santamaría
- Departamento
de Química Orgánica y Química Inorgánica,
Instituto de Investigación Química “Andrés
M. del Río” (IQAR), Universidad
de Alcalá, Campus
Universitario, E-28805 Alcalá de Henares, Madrid, Spain
| | - Josep M. Luis
- Institute
of Computational Chemistry and Catalysis and Department of Chemistry, University of Girona, Campus de Montilivi, 17003 Girona, Catalonia, Spain
| | - Alberto Hernán-Gómez
- Departamento
de Química Orgánica y Química Inorgánica,
Instituto de Investigación Química “Andrés
M. del Río” (IQAR), Universidad
de Alcalá, Campus
Universitario, E-28805 Alcalá de Henares, Madrid, Spain
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2
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Ballmann GM, Gentner TX, Kennedy AR, Hevia E, Mulvey RE. Heavy Alkali Metal Manganate Complexes: Synthesis, Structures and Solvent-Induced Dissociation Effects. Chemistry 2022; 28:e202201716. [PMID: 35775467 PMCID: PMC9804227 DOI: 10.1002/chem.202201716] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Indexed: 01/05/2023]
Abstract
Rare examples of heavier alkali metal manganates [{(AM)Mn(CH2 SiMe3 )(N'Ar )2 }∞ ] (AM=K, Rb, or Cs) [N'Ar =N(SiMe3 )(Dipp), where Dipp=2,6-iPr2 -C6 H3 ] have been synthesised with the Rb and Cs examples crystallographically characterised. These heaviest manganates crystallise as polymeric zig-zag chains propagated by AM⋅⋅⋅π-arene interactions. Key to their preparation is to avoid Lewis base donor solvents. In contrast, using multidentate nitrogen donors encourages ligand scrambling leading to redistribution of these bimetallic manganate compounds into their corresponding homometallic species as witnessed for the complete Li - Cs series. Adding to the few known crystallographically characterised unsolvated and solvated rubidium and caesium s-block metal amides, six new derivatives ([{AM(N'Ar )}∞ ], [{AM(N'Ar )⋅TMEDA}∞ ], and [{AM(N'Ar )⋅PMDETA}∞ ] where AM=Rb or Cs) have been structurally authenticated. Utilising monodentate diethyl ether as a donor, it was also possible to isolate and crystallographically characterise sodium manganate [(Et2 O)2 Na(n Bu)Mn[(N'Ar )2 ], a monomeric, dinuclear structure prevented from aggregating by two blocking ether ligands bound to sodium.
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Affiliation(s)
- Gerd M. Ballmann
- WestCHEMDepartment of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Thomas X. Gentner
- WestCHEMDepartment of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Alan R. Kennedy
- WestCHEMDepartment of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Eva Hevia
- Department für Chemie und BiochemieUniversität BernFreiestrasse 33012BernSwitzerland
| | - Robert E. Mulvey
- WestCHEMDepartment of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
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Götz T, Falk A, Bauer JO. Molecular Scissors for Tailor-Made Modification of Siloxane Scaffolds. Chemistry 2022; 28:e202103531. [PMID: 34761842 PMCID: PMC9299477 DOI: 10.1002/chem.202103531] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Indexed: 01/07/2023]
Abstract
The controlled design of functional oligosiloxanes is an important topic in current research. A consecutive Si-O-Si bond cleavage/formation using siloxanes that are substituted with 1,2-diaminobenzene derivatives acting as molecular scissors is presented. The method allows to cut at certain positions of a siloxane scaffold forming a cyclic diaminosilane or -siloxane intermediate and then to introduce new functional siloxy units. The procedure could be extended to a direct one-step cleavage of chlorooligosiloxanes. Both siloxane formation and cleavage proceed with good to excellent yields, high regioselectivity, and great variability of the siloxy units. Control of the selectivity is achieved by the choice of the amino substituent. Insight into the mechanism was provided by low temperature NMR studies and the isolation of a lithiated intermediate.
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Affiliation(s)
- Tobias Götz
- Institut für Anorganische Chemie, Fakultät für Chemie und PharmazieUniversität RegensburgUniversitätsstraße 31D-93053RegensburgGermany
| | - Alexander Falk
- Institut für Anorganische Chemie, Fakultät für Chemie und PharmazieUniversität RegensburgUniversitätsstraße 31D-93053RegensburgGermany
| | - Jonathan O. Bauer
- Institut für Anorganische Chemie, Fakultät für Chemie und PharmazieUniversität RegensburgUniversitätsstraße 31D-93053RegensburgGermany
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4
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Duraisamy R, Liebing P, Harmgarth N, Lorenz V, Hilfert L, Busse S, Engelhardt F, Edelmann FT. The Manifold Structural Chemistry of Alkali Metal Enediamide Complexes. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201900559] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ramesh Duraisamy
- Chemisches Institut der Otto‐von‐Guericke‐Universität Magdeburg Universitätsplatz 2 D‐39106 Magdeburg Germany
| | - Phil Liebing
- Chemisches Institut der Otto‐von‐Guericke‐Universität Magdeburg Universitätsplatz 2 D‐39106 Magdeburg Germany
| | - Nicole Harmgarth
- Chemisches Institut der Otto‐von‐Guericke‐Universität Magdeburg Universitätsplatz 2 D‐39106 Magdeburg Germany
| | - Volker Lorenz
- Chemisches Institut der Otto‐von‐Guericke‐Universität Magdeburg Universitätsplatz 2 D‐39106 Magdeburg Germany
| | - Liane Hilfert
- Chemisches Institut der Otto‐von‐Guericke‐Universität Magdeburg Universitätsplatz 2 D‐39106 Magdeburg Germany
| | - Sabine Busse
- Chemisches Institut der Otto‐von‐Guericke‐Universität Magdeburg Universitätsplatz 2 D‐39106 Magdeburg Germany
| | - Felix Engelhardt
- Chemisches Institut der Otto‐von‐Guericke‐Universität Magdeburg Universitätsplatz 2 D‐39106 Magdeburg Germany
| | - Frank T. Edelmann
- Chemisches Institut der Otto‐von‐Guericke‐Universität Magdeburg Universitätsplatz 2 D‐39106 Magdeburg Germany
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5
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6
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Haeri HH, Duraisamy R, Harmgarth N, Liebing P, Lorenz V, Hinderberger D, Edelmann FT. Electronic and Geometric Structures of Paramagnetic Diazadiene Complexes of Lithium and Sodium. ChemistryOpen 2018; 7:701-708. [PMID: 30202705 PMCID: PMC6123648 DOI: 10.1002/open.201800114] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Indexed: 11/08/2022] Open
Abstract
The electronic and molecular structures of the lithium and sodium complexes of 1,4-bis(2,6-diisopropylphenyl)-2,3-dimethyl-1,4-diazabutadiene (Me2DADDipp) were fully characterized by using a multi-frequency electron paramagnetic resonance (EPR) spectroscopy approach and crystallography, together with density functional theory (DFT) calculations. EPR measurements, using T1 relaxation-time-filtered pulse EPR spectroscopy, revealed the diagonal elements of the A and g tensors for the metal and ligand sites. It was found that the central metals in the lithium complexes had sizable contributions to the SOMO, whereas this contribution was less strongly observed for the sodium complex. Such strong contributions were attributed to structural specifications (e.g. geometrical data and atomic size) rather than electronic effects.
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Affiliation(s)
- Haleh H. Haeri
- Institute of ChemistryMartin Luther University Halle-WittenbergVon-Danckelmann-Platz 406120HalleGermany
| | - Ramesh Duraisamy
- Institute of ChemistryOtto-von-Guericke UniversityMagdeburg39106Germany
| | - Nicole Harmgarth
- Institute of ChemistryOtto-von-Guericke UniversityMagdeburg39106Germany
| | - Phil Liebing
- Laboratory for Inorganic ChemistryETH ZürichVladimir-Prelog-Weg 28093ZürichSwitzerland
| | - Volker Lorenz
- Institute of ChemistryOtto-von-Guericke UniversityMagdeburg39106Germany
| | - Dariush Hinderberger
- Institute of ChemistryMartin Luther University Halle-WittenbergVon-Danckelmann-Platz 406120HalleGermany
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7
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Leconte N, Moutet J, Constantin T, Molton F, Philouze C, Thomas F. Coordination Chemistry of the Redox Non-Innocent Ligand Bis(2-amino-3,5-di-tert
-butylphenyl)amine with Group 10 Metal Ions (Ni, Pd, Pt). Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201701448] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Nicolas Leconte
- Département de Chimie Moléculaire, UMR-5250; Université Grenoble Alpes; BP 53 38041 Grenoble Cedex 9 France
| | - Jules Moutet
- Département de Chimie Moléculaire, UMR-5250; Université Grenoble Alpes; BP 53 38041 Grenoble Cedex 9 France
| | - Thibaut Constantin
- Département de Chimie Moléculaire, UMR-5250; Université Grenoble Alpes; BP 53 38041 Grenoble Cedex 9 France
| | - Florian Molton
- Département de Chimie Moléculaire, UMR-5250; Université Grenoble Alpes; BP 53 38041 Grenoble Cedex 9 France
| | - Christian Philouze
- Département de Chimie Moléculaire, UMR-5250; Université Grenoble Alpes; BP 53 38041 Grenoble Cedex 9 France
| | - Fabrice Thomas
- Département de Chimie Moléculaire, UMR-5250; Université Grenoble Alpes; BP 53 38041 Grenoble Cedex 9 France
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8
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Ziemann S, Krieck S, Görls H, Westerhausen M. 1,2-Bis(anilido)ethane Complexes of Calcium and Potassium: Synthesis, Structures, and Catalytic Activity. Organometallics 2018. [DOI: 10.1021/acs.organomet.7b00890] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Steffen Ziemann
- 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
| | - Matthias Westerhausen
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, D-07743 Jena, Germany
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9
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Moutet J, Philouze C, du Moulinet d'Hardemare A, Leconte N, Thomas F. Ni(II) Complexes of the Redox-Active Bis(2-aminophenyl)dipyrrin: Structural, Spectroscopic, and Theoretical Characterization of Three Members of an Electron Transfer Series. Inorg Chem 2017; 56:6380-6392. [PMID: 28513171 DOI: 10.1021/acs.inorgchem.7b00433] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The sterically hindered bis(2-aminophenyl)dipyrrin ligand H3NL was prepared. X-ray diffraction discloses a bifurcated hydrogen bonding network involving the dipyrrin and one aniline ring. The reaction of H3NL with one equivalent of nickel(II) in the air produces a paramagnetic neutral complex, which absorbs intensively in the Vis-NIR region. Its electron paramagnetic resonance spectrum displays resonances at g1 = 2.033, g2 = 2.008, and g3 = 1.962 that are reminiscent of an (S = 1/2) system having a predominant organic radical character. Both the structural investigation (X-ray diffraction) and density functional theory calculations on [NiII(NL•)] points to an unprecedented mixed "pyrrolyl-anilinyl" radical character. The neutral complex [NiII(NL•)] exhibits both a reversible oxidation wave at -0.28 V vs Fc+/Fc and a reversible reduction wave at -0.91 V. The anion was found to be highly air-sensitive, but could be prepared by reduction with cobaltocene and structurally characterized. It comprises a Ni(II) ion coordinated to a closed-shell trianionic ligand and hence can be formulated as [NiII(NL)]-. The cation was generated by reacting [NiII(NL•)] with one equivalent of silver hexafluoroantimonate. By X-ray diffraction we established that it contains an oxidized, closed-shell ligand coordinated to a nickel(II) ion. We found that a reliable hallmark for both the oxidation state of the ligand and the extent of delocalization within the series is the bond connecting the dipyrrin and the aniline, which ranges between 1.391 Å (cation) and 1.449 Å (anion). The cation and anion exhibit a rich Vis-NIR spectrum, despite their nonradical nature. The low energy bands correspond to ligand-based electronic excitations. Hence, the HOMO-LUMO gap is small, and the redox processes in the electron transfer series are exclusively ligand-centered.
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Affiliation(s)
- Jules Moutet
- Département de Chimie Moléculaire - Chimie Inorganique Redox (CIRE) - UMR CNRS 5250, Université Grenoble Alpes , B. P. 53, 38041 Grenoble cedex 9, France
| | - Christian Philouze
- Département de Chimie Moléculaire - Chimie Inorganique Redox (CIRE) - UMR CNRS 5250, Université Grenoble Alpes , B. P. 53, 38041 Grenoble cedex 9, France
| | - Amaury du Moulinet d'Hardemare
- Département de Chimie Moléculaire - Chimie Inorganique Redox (CIRE) - UMR CNRS 5250, Université Grenoble Alpes , B. P. 53, 38041 Grenoble cedex 9, France
| | - Nicolas Leconte
- Département de Chimie Moléculaire - Chimie Inorganique Redox (CIRE) - UMR CNRS 5250, Université Grenoble Alpes , B. P. 53, 38041 Grenoble cedex 9, France
| | - Fabrice Thomas
- Département de Chimie Moléculaire - Chimie Inorganique Redox (CIRE) - UMR CNRS 5250, Université Grenoble Alpes , B. P. 53, 38041 Grenoble cedex 9, France
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10
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Zhong F, Yang X, Shen L, Zhao Y, Ma H, Wu B, Yang XJ. Multinuclear Alkali Metal Complexes of a Triphenylene-Based Hexamine and the Transmetalation to Tris(N-heterocyclic tetrylenes) (Ge, Sn, Pb). Inorg Chem 2016; 55:9112-20. [DOI: 10.1021/acs.inorgchem.6b01743] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Fei Zhong
- Key Laboratory of Synthetic and Natural
Functional Molecule Chemistry of the Ministry of Education, College
of Chemistry and Materials Science, Northwest University, Xi’an 710069, China
| | - Xiaodong Yang
- Key Laboratory of Synthetic and Natural
Functional Molecule Chemistry of the Ministry of Education, College
of Chemistry and Materials Science, Northwest University, Xi’an 710069, China
| | - Lingyi Shen
- Key Laboratory of Synthetic and Natural
Functional Molecule Chemistry of the Ministry of Education, College
of Chemistry and Materials Science, Northwest University, Xi’an 710069, China
| | - Yanxia Zhao
- Key Laboratory of Synthetic and Natural
Functional Molecule Chemistry of the Ministry of Education, College
of Chemistry and Materials Science, Northwest University, Xi’an 710069, China
| | - Hongwei Ma
- Analysis
and Testing Center, Beijing Institute of Technology, Beijing 102488, China
| | - Biao Wu
- Key Laboratory of Synthetic and Natural
Functional Molecule Chemistry of the Ministry of Education, College
of Chemistry and Materials Science, Northwest University, Xi’an 710069, China
| | - Xiao-Juan Yang
- Key Laboratory of Synthetic and Natural
Functional Molecule Chemistry of the Ministry of Education, College
of Chemistry and Materials Science, Northwest University, Xi’an 710069, China
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11
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Bera S, Mondal S, Maity S, Weyhermüller T, Ghosh P. Radical and Non-Radical States of the [Os(PIQ)] Core (PIQ = 9,10-Phenanthreneiminoquinone): Iminosemiquinone to Iminoquinone Conversion Promoted o-Metalation Reaction. Inorg Chem 2016; 55:4746-56. [DOI: 10.1021/acs.inorgchem.6b00040] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sachinath Bera
- Department
of Chemistry, R. K. Mission Residential College, Narendrapur, Kolkata 103, India
| | - Sandip Mondal
- Department
of Chemistry, R. K. Mission Residential College, Narendrapur, Kolkata 103, India
| | - Suvendu Maity
- Department
of Chemistry, R. K. Mission Residential College, Narendrapur, Kolkata 103, India
| | - Thomas Weyhermüller
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim, Germany
| | - Prasanta Ghosh
- Department
of Chemistry, R. K. Mission Residential College, Narendrapur, Kolkata 103, India
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12
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Martinez-Ariza G, Ayaz M, Roberts SA, Rabanal-León WA, Arratia-Pérez R, Hulme C. The Synthesis of Stable, Complex Organocesium Tetramic Acids through the Ugi Reaction and Cesium-Carbonate-Promoted Cascades. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201504377] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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13
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Ziemann S, Krieck S, Görls H, Westerhausen M. Potassium and Mixed Lithium/Potassium Complexes of Deprotonated 1,2-Bis(neopentylamino)benzene. Z Anorg Allg Chem 2015. [DOI: 10.1002/zaac.201500521] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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14
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Martinez‐Ariza G, Ayaz M, Roberts SA, Rabanal‐León WA, Arratia‐Pérez R, Hulme C. The Synthesis of Stable, Complex Organocesium Tetramic Acids through the Ugi Reaction and Cesium‐Carbonate‐Promoted Cascades. Angew Chem Int Ed Engl 2015; 54:11672-6. [DOI: 10.1002/anie.201504377] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 07/16/2015] [Indexed: 11/07/2022]
Affiliation(s)
- Guillermo Martinez‐Ariza
- Department of Pharmacology and Toxicology, The University of Arizona, BSW Room #351, 1041 E. Lowell St., Tucson, AZ 85721 (USA)
| | - Muhammad Ayaz
- Department of Pharmacology and Toxicology, The University of Arizona, BSW Room #351, 1041 E. Lowell St., Tucson, AZ 85721 (USA)
| | - Sue A. Roberts
- Department of Chemistry and Biochemistry, The University of Arizona (USA)
| | - Walter A. Rabanal‐León
- Universidad Andrés Bello, Facultad de Ciencias Exactas, Ph.D. Program in Molecular Physical Chemistry, Relativistic Molecular Physics (ReMoPhys) Group, Av. República 275, Santiago 8370146 (Chile)
| | - Ramiro Arratia‐Pérez
- Universidad Andrés Bello, Facultad de Ciencias Exactas, Ph.D. Program in Molecular Physical Chemistry, Relativistic Molecular Physics (ReMoPhys) Group, Av. República 275, Santiago 8370146 (Chile)
| | - Christopher Hulme
- Department of Pharmacology and Toxicology, The University of Arizona, BSW Room #351, 1041 E. Lowell St., Tucson, AZ 85721 (USA)
- Department of Chemistry and Biochemistry, The University of Arizona (USA)
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15
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Das A, Ghosh P, Plebst S, Schwederski B, Mobin SM, Kaim W, Lahiri GK. Ancillary Ligand Control of Electronic Structure in o-Benzoquinonediimine-Ruthenium Complex Redox Series: Structures, Electron Paramagnetic Resonance (EPR), and Ultraviolet−Visible−Near-Infrared (UV-vis-NIR) Spectroelectrochemistry. Inorg Chem 2015; 54:3376-86. [DOI: 10.1021/ic503070j] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ankita Das
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Prabir Ghosh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sebastian Plebst
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany
| | - Brigitte Schwederski
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany
| | - Shaikh M. Mobin
- Discipline of Chemistry,
School of Basic Sciences, Indian Institute of Technology Indore, Indore 452017, India
| | - Wolfgang Kaim
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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16
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Xu H, Muto K, Yamaguchi J, Zhao C, Itami K, Musaev DG. Key mechanistic features of Ni-catalyzed C-H/C-O biaryl coupling of azoles and naphthalen-2-yl pivalates. J Am Chem Soc 2014; 136:14834-44. [PMID: 25259782 DOI: 10.1021/ja5071174] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The mechanism of the Ni-dcype-catalyzed C-H/C-O coupling of benzoxazole and naphthalen-2-yl pivalate was studied. Special attention was devoted to the base effect in the C-O oxidative addition and C-H activation steps as well as the C-H substrate effect in the C-H activation step. No base effect in the C(aryl)-O oxidative addition to Ni-dcype was found, but the nature of the base and C-H substrate plays a crucial role in the following C-H activation. In the absence of base, the azole C-H activation initiated by the C-O oxidative addition product Ni(dcype)(Naph)(PivO), 1B, proceeds via ΔG = 34.7 kcal/mol barrier. Addition of Cs2CO3 base to the reaction mixture forms the Ni(dcype)(Naph)[PivOCs·CsCO3], 3_Cs_clus, cluster complex rather than undergoing PivO(-) → CsCO3(-) ligand exchange. Coordination of azole to the resulting 3_Cs_clus complex forms intermediate with a weak Cs-heteroatom(azole) bond, the existence of which increases acidity of the activated C-H bond and reduces C-H activation barrier. This conclusion from computation is consistent with experiments showing that the addition of Cs2CO3 to the reaction mixture of 1B and benzoxazole increases yield of C-H/C-O coupling from 32% to 67% and makes the reaction faster by 3-fold. This emerging mechanistic knowledge was validated by further exploring base and C-H substrate effects via replacing Cs2CO3 with K2CO3 and benzoxazole (1a) with 1H-benzo[d]imidazole (1b) or quinazoline (1c). We proposed the modified catalytic cycle for the Ni(cod)(dcype)-catalyzed C-H/C-O coupling of benzoxazole and naphthalen-2-yl pivalate.
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Affiliation(s)
- Huiying Xu
- Cherry L. Emerson Center for Scientific Computation, Emory University , 1515 Dickey Drive, Atlanta, Georgia 30322, United States
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