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The Backbone of Success of P,N-Hybrid Ligands: Some Recent Developments. Molecules 2022; 27:molecules27196293. [PMID: 36234830 PMCID: PMC9614609 DOI: 10.3390/molecules27196293] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/21/2022] [Accepted: 09/21/2022] [Indexed: 12/03/2022] Open
Abstract
Organophosphorus ligands are an invaluable family of compounds that continue to underpin important roles in disciplines such as coordination chemistry and catalysis. Their success can routinely be traced back to facile tuneability thus enabling a high degree of control over, for example, electronic and steric properties. Diphosphines, phosphorus compounds bearing two separated PIII donor atoms, are also highly valued and impart their own unique features, for example excellent chelating properties upon metal complexation. In many classical ligands of this type, the backbone connectivity has been based on all carbon spacers only but there is growing interest in embedding other donor atoms such as additional nitrogen (–NH–, –NR–) sites. This review will collate some important examples of ligands in this field, illustrate their role as ligands in coordination chemistry and highlight some of their reactivities and applications. It will be shown that incorporation of a nitrogen-based group can impart unusual reactivities and important catalytic applications.
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Das K, Barman MK, Maji B. Advancements in multifunctional manganese complexes for catalytic hydrogen transfer reactions. Chem Commun (Camb) 2021; 57:8534-8549. [PMID: 34369488 DOI: 10.1039/d1cc02512k] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Catalytic hydrogen transfer reactions have enormous academic and industrial applications for the production of diverse molecular scaffolds. Over the past few decades, precious late transition-metal catalysts were employed for these reactions. The early transition metals have recently gained much attention due to their lower cost, less toxicity, and overall sustainability. In this regard, manganese, which is the third most abundant transition metal in the Earth's crust, has emerged as a viable alternative. However, the key to the success of such manganese-based complexes lies in the multifunctional ligand design and choice of appropriate ancillary ligands, which helps them mimic and, even in some cases, supersede noble metals' activities. The metal-ligand bifunctionality, achieved via deprotonation of the acidic C-H or N-H bonds, is one of the powerful strategies employed for this purpose. Alongside, the ligand hemilability in which a weakly chelating group tunes in between the coordinated and uncoordinated stages could effectively stabilize the reactive intermediates, thereby facilitating substrate activation and catalysis. Redox non-innocent ligands acting as an electron sink, thereby helping the metal center in steps gaining or losing electrons, and non-classical metal-ligand cooperativity has also played a significant role in the ligand design for manganese catalysis. The strategies were not only employed for the chemoselective hydrogenation of different reducible functionalities but also for the C-X (X = C/N) coupling reactions via HT and downstream cascade processes. This article features multifunctional ligand-based manganese complexes, highlighting the importance of ligand design and choice of ancillary ligands for achieving the desired catalytic activity and selectivity for HT reactions. We have also discussed the detailed reaction pathways for metal complexes involving bifunctionality, hemilability, redox activity, and indirect metal-ligand cooperativity. The synthetic utilization of those complexes in different organic transformations has also been detailed.
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Affiliation(s)
- Kuhali Das
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India.
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Elsby MR, Son M, Oh C, Martin J, Baik MH, Baker RT. Mechanistic Study of Metal–Ligand Cooperativity in Mn(II)-Catalyzed Hydroborations: Hemilabile SNS Ligand Enables Metal Hydride-Free Reaction Pathway. ACS Catal 2021. [DOI: 10.1021/acscatal.1c02238] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Matthew R. Elsby
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Mina Son
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) and Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Changjin Oh
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) and Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Jessica Martin
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Mu-Hyun Baik
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) and Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - R. Tom Baker
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
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Ott JC, Isak D, Melder JJ, Wadepohl H, Gade LH. Single or Paired? Structure and Reactivity of PNP-Chromium(II) Hydrides. Inorg Chem 2020; 59:14526-14535. [PMID: 32931701 DOI: 10.1021/acs.inorgchem.0c02315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The preparation and reactivity of a range of novel paramagnetic chromium(II) complexes supported by a carbazole-based PNP pincer ligand is reported. Deprotonation of the ligand precursors R(PNP)H (1R) and subsequent reaction with chromium(II) chloride led to the formation of square-planar chlorido complexes R(PNP)CrCl (2R). Further reaction with various alkylating agents resulted in the isolation of chromium alkyl complexes R(PNP)CrR' (3R-R') which were then hydrogenated to yield two rare examples of paramagnetic chromium(II) hydrides 4iPr and 4tBu. Both compounds were characterized by X-ray diffraction and paramagnetic NMR spectroscopy supported by a comprehensive DFT-supported assignment of the resonances. While the di(tert-butyl)phosphino PNP substituted complex 4tBu was found to exhibit a monomeric square-planar molecular structure, its isopropyl-substituted analog 4iPr forms a dimer, also indicated by a strong antiferromagnetic coupling of the chromium centers. The pronounced reactivity of these compounds toward C═X double bonds was demonstrated by reaction with benzophenone, N,N'-dicyclohexylcarbodiimide, and carbon dioxide, which gave the corresponding insertion products. The alkoxido complex 5iPr, the amidinato complex 6iPr, and the formato compound 7tBu were also characterized by X-ray diffraction.
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Affiliation(s)
- Jonas C Ott
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Daniel Isak
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Julian J Melder
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Hubert Wadepohl
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Lutz H Gade
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
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Sharma DM, Punji B. 3 d Transition Metal‐Catalyzed Hydrogenation of Nitriles and Alkynes. Chem Asian J 2020; 15:690-708. [DOI: 10.1002/asia.201901762] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/27/2020] [Indexed: 11/09/2022]
Affiliation(s)
- Dipesh M. Sharma
- Chemical Engineering DivisionCSIR-National Chemical Laboratory (CSIR-NCL) Academy of Scientific and Innovative Research (AcSIR) Dr. Homi Bhabha Road Pune 411 008 India
| | - Benudhar Punji
- Chemical Engineering DivisionCSIR-National Chemical Laboratory (CSIR-NCL) Academy of Scientific and Innovative Research (AcSIR) Dr. Homi Bhabha Road Pune 411 008 India
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Importance of thorough conformational analysis in modelling transition metal-mediated reactions: Case studies on pincer complexes containing phosphine groups. JOURNAL OF SAUDI CHEMICAL SOCIETY 2019. [DOI: 10.1016/j.jscs.2019.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Narro AL, Arman HD, Tonzetich ZJ. Manganese Chemistry of Anionic Pyrrole-Based Pincer Ligands. Organometallics 2019. [DOI: 10.1021/acs.organomet.9b00058] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ana L. Narro
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
| | - Hadi D. Arman
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
| | - Zachary J. Tonzetich
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
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8
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Liu H, Yuan H, Shi X. Synthesis of nickel and palladium complexes with diarylamido-based unsymmetrical pincer ligands and application for norbornene polymerization. Dalton Trans 2019; 48:609-617. [PMID: 30534670 DOI: 10.1039/c8dt04413a] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A set of diarylamido-based unsymmetrical [PNNox] pincer ligands containing a chiral oxazoline ring have been synthesized and their nickel and palladium complexes [(2-PPh2(R1)ArN(R1)Ar-2-(R)oxazoline)MCl] (R1 = 4-H, R = (S)-4-iPr, M = Pd (Pd1); R1 = 4-H, R = (S)-4-Bn, M = Pd (Pd2); R1 = 4-H, R = (S)-4-Ph, M = Pd (Pd3); R1 = 4-Me, R = (S)-4-Bn, M = Pd (Pd4); R1 = 4-Me, R = (S)-4-Ph, M = Pd (Pd5); R1 = 4-H, R = 4-Me2, M = Pd (Pd6); R1 = 4-H, R = Benzo[d]-, M = Pd (Pd7); R1 = 4-H, R = (S)-4-Bn, M = Ni (Ni1); R1 = 4-H, R = (S)-4-Ph, M = Ni (Ni2); R1 = 4-Me, R = (S)-4-Bn, M = Ni (Ni3); R1 = 4-Me, R = (S)-4-Ph, M = Pd (Ni4)) were tested to show high catalytic activities for polymerization of norbornene. After activation of methylaluminoxane (MAO), all the nickel and palladium complexes could catalyze the polymerization of norbornene to yield vinyl-type polymers with activities up to 40.3 × 105 g of PNB (mol of Pd)-1 h-1. The copolymerization of norbornene with functional norbornene comonomers was also investigated by catalyst Pd2, accompanied by decreased catalytic activity and low incorporation of functional comonomers.
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Affiliation(s)
- Hui Liu
- Department of Polymer Materials, College of Materials Science and Engineering, Shanghai University, Materials Building, Nanchen Street 333, Shanghai 200444, China.
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9
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Thompson CV, Davis I, DeGayner JA, Arman HD, Tonzetich ZJ. Iron Pincer Complexes Incorporating Bipyridine: A Strategy for Stabilization of Reactive Species. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00772] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- C. Vance Thompson
- Department
of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
| | - Ian Davis
- Department
of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
| | - Jordan A. DeGayner
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Hadi D. Arman
- Department
of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
| | - Zachary J. Tonzetich
- Department
of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
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Liu W, Cera G, Oliveira JCA, Shen Z, Ackermann L. MnCl2
-Catalyzed C−H Alkylations with Alkyl Halides. Chemistry 2017; 23:11524-11528. [DOI: 10.1002/chem.201703191] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Indexed: 11/05/2022]
Affiliation(s)
- Weiping Liu
- Institut für Organische und Biomolekulare Chemie; Georg-August-Universität; Tammannstraße 2 37077 Göttingen Germany
| | - Gianpiero Cera
- Institut für Organische und Biomolekulare Chemie; Georg-August-Universität; Tammannstraße 2 37077 Göttingen Germany
| | - João C. A. Oliveira
- Institut für Organische und Biomolekulare Chemie; Georg-August-Universität; Tammannstraße 2 37077 Göttingen Germany
| | - Zhigao Shen
- Institut für Organische und Biomolekulare Chemie; Georg-August-Universität; Tammannstraße 2 37077 Göttingen Germany
| | - Lutz Ackermann
- Institut für Organische und Biomolekulare Chemie; Georg-August-Universität; Tammannstraße 2 37077 Göttingen Germany
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Papa V, Cabrero-Antonino JR, Alberico E, Spanneberg A, Junge K, Junge H, Beller M. Efficient and selective hydrogenation of amides to alcohols and amines using a well-defined manganese-PNN pincer complex. Chem Sci 2017; 8:3576-3585. [PMID: 30155202 PMCID: PMC6092716 DOI: 10.1039/c7sc00138j] [Citation(s) in RCA: 144] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 02/24/2017] [Indexed: 12/23/2022] Open
Abstract
Novel well-defined NNP and PNP manganese pincer complexes have been synthetized and fully characterized. The catalyst Mn-2 containing an imidazolyaminolphosphino ligand shows high activity and selectivity in the hydrogenation of a wide range of secondary and tertiary amides to the corresponding alcohols and amines, under relatively mild conditions. For the first time, more challenging substrates like primary aromatic amides including an actual herbicide can also be hydrogenated using this earth-abundant metal-based pincer catalyst.
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Affiliation(s)
- Veronica Papa
- Leibniz-Institut für Katalyse , e.V. Albert-Einstein Str. 29a , 18059 Rostock , Germany .
| | | | - Elisabetta Alberico
- Leibniz-Institut für Katalyse , e.V. Albert-Einstein Str. 29a , 18059 Rostock , Germany .
- Instituto di Chimica Biomolecolare , Consiglio Nazionale delle Ricerche , Tr. La Crucca 3 , 07100 Sassari , Italy
| | - Anke Spanneberg
- Leibniz-Institut für Katalyse , e.V. Albert-Einstein Str. 29a , 18059 Rostock , Germany .
| | - Kathrin Junge
- Leibniz-Institut für Katalyse , e.V. Albert-Einstein Str. 29a , 18059 Rostock , Germany .
| | - Henrik Junge
- Leibniz-Institut für Katalyse , e.V. Albert-Einstein Str. 29a , 18059 Rostock , Germany .
| | - Matthias Beller
- Leibniz-Institut für Katalyse , e.V. Albert-Einstein Str. 29a , 18059 Rostock , Germany .
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12
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Elangovan S, Neumann J, Sortais JB, Junge K, Darcel C, Beller M. Efficient and selective N-alkylation of amines with alcohols catalysed by manganese pincer complexes. Nat Commun 2016; 7:12641. [PMID: 27708259 PMCID: PMC5059641 DOI: 10.1038/ncomms12641] [Citation(s) in RCA: 429] [Impact Index Per Article: 53.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/20/2016] [Indexed: 12/23/2022] Open
Abstract
Borrowing hydrogen (or hydrogen autotransfer) reactions represent straightforward and sustainable C–N bond-forming processes. In general, precious metal-based catalysts are employed for this effective transformation. In recent years, the use of earth abundant and cheap non-noble metal catalysts for this process attracted considerable attention in the scientific community. Here we show that the selective N-alkylation of amines with alcohols can be catalysed by defined PNP manganese pincer complexes. A variety of substituted anilines are monoalkylated with different (hetero)aromatic and aliphatic alcohols even in the presence of other sensitive reducible functional groups. As a special highlight, we report the chemoselective monomethylation of primary amines using methanol under mild conditions. Hydrogen borrowing is an attractive method for C-N bond formation - avoiding multiple alkylation products and reducing waste - but often is carried out with noble metals. Here the authors show that a manganese catalyst allows the selective N-alkylation of amines with alcohols.
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Affiliation(s)
- Saravanakumar Elangovan
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, Rostock 18059, Germany.,UMR 6226 CNRS-Université de Rennes 1 Institut des Sciences Chimiques de Rennes, Team Organometallics: Materials and Catalysis-Centre for Catalysis and Green Chemistry, campus de Beaulieu, 35042 Rennes, France
| | - Jacob Neumann
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, Rostock 18059, Germany
| | - Jean-Baptiste Sortais
- UMR 6226 CNRS-Université de Rennes 1 Institut des Sciences Chimiques de Rennes, Team Organometallics: Materials and Catalysis-Centre for Catalysis and Green Chemistry, campus de Beaulieu, 35042 Rennes, France
| | - Kathrin Junge
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, Rostock 18059, Germany
| | - Christophe Darcel
- UMR 6226 CNRS-Université de Rennes 1 Institut des Sciences Chimiques de Rennes, Team Organometallics: Materials and Catalysis-Centre for Catalysis and Green Chemistry, campus de Beaulieu, 35042 Rennes, France
| | - Matthias Beller
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, Rostock 18059, Germany
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Elangovan S, Garbe M, Jiao H, Spannenberg A, Junge K, Beller M. Hydrogenation of Esters to Alcohols Catalyzed by Defined Manganese Pincer Complexes. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201607233] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Saravanakumar Elangovan
- Leibniz-Institut für Katalyse e. V. an der Universität Rostock; Albert-Einstein Strasse 29a Rostock 18059 Germany
| | - Marcel Garbe
- Leibniz-Institut für Katalyse e. V. an der Universität Rostock; Albert-Einstein Strasse 29a Rostock 18059 Germany
| | - Haijun Jiao
- Leibniz-Institut für Katalyse e. V. an der Universität Rostock; Albert-Einstein Strasse 29a Rostock 18059 Germany
| | - Anke Spannenberg
- Leibniz-Institut für Katalyse e. V. an der Universität Rostock; Albert-Einstein Strasse 29a Rostock 18059 Germany
| | - Kathrin Junge
- Leibniz-Institut für Katalyse e. V. an der Universität Rostock; Albert-Einstein Strasse 29a Rostock 18059 Germany
| | - Matthias Beller
- Leibniz-Institut für Katalyse e. V. an der Universität Rostock; Albert-Einstein Strasse 29a Rostock 18059 Germany
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Elangovan S, Garbe M, Jiao H, Spannenberg A, Junge K, Beller M. Hydrogenation of Esters to Alcohols Catalyzed by Defined Manganese Pincer Complexes. Angew Chem Int Ed Engl 2016; 55:15364-15368. [PMID: 27690363 DOI: 10.1002/anie.201607233] [Citation(s) in RCA: 219] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Indexed: 12/21/2022]
Abstract
The first manganese-catalyzed hydrogenation of esters to alcohols has been developed. The combination of Mn(CO)5 Br with [HN(CH2 CH2 P(Et)2 )2 ] leads to a mixture of cationic and neutral Mn PNP pincer complexes, which enable the reduction of various ester substrates, including aromatic and aliphatic esters as well as diesters and lactones. Notably, related pincer complexes with isopropyl or cyclohexyl substituents showed very low activity.
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Affiliation(s)
- Saravanakumar Elangovan
- Leibniz-Institut für Katalyse e. V. an der Universität Rostock, Albert-Einstein Strasse 29a, Rostock, 18059, Germany
| | - Marcel Garbe
- Leibniz-Institut für Katalyse e. V. an der Universität Rostock, Albert-Einstein Strasse 29a, Rostock, 18059, Germany
| | - Haijun Jiao
- Leibniz-Institut für Katalyse e. V. an der Universität Rostock, Albert-Einstein Strasse 29a, Rostock, 18059, Germany
| | - Anke Spannenberg
- Leibniz-Institut für Katalyse e. V. an der Universität Rostock, Albert-Einstein Strasse 29a, Rostock, 18059, Germany
| | - Kathrin Junge
- Leibniz-Institut für Katalyse e. V. an der Universität Rostock, Albert-Einstein Strasse 29a, Rostock, 18059, Germany
| | - Matthias Beller
- Leibniz-Institut für Katalyse e. V. an der Universität Rostock, Albert-Einstein Strasse 29a, Rostock, 18059, Germany
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Tondreau AM, Boncella JM. The synthesis of PNP-supported low-spin nitro manganese(I) carbonyl complexes. Polyhedron 2016. [DOI: 10.1016/j.poly.2016.04.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Elangovan S, Topf C, Fischer S, Jiao H, Spannenberg A, Baumann W, Ludwig R, Junge K, Beller M. Selective Catalytic Hydrogenations of Nitriles, Ketones, and Aldehydes by Well-Defined Manganese Pincer Complexes. J Am Chem Soc 2016; 138:8809-14. [PMID: 27219853 DOI: 10.1021/jacs.6b03709] [Citation(s) in RCA: 387] [Impact Index Per Article: 48.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hydrogenations constitute fundamental processes in organic chemistry and allow for atom-efficient and clean functional group transformations. In fact, the selective reduction of nitriles, ketones, and aldehydes with molecular hydrogen permits access to a green synthesis of valuable amines and alcohols. Despite more than a century of developments in homogeneous and heterogeneous catalysis, efforts toward the creation of new useful and broadly applicable catalyst systems are ongoing. Recently, Earth-abundant metals have attracted significant interest in this area. In the present study, we describe for the first time specific molecular-defined manganese complexes that allow for the hydrogenation of various polar functional groups. Under optimal conditions, we achieve good functional group tolerance, and industrially important substrates, e.g., for the flavor and fragrance industry, are selectively reduced.
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Affiliation(s)
| | - Christoph Topf
- Leibniz-Institut für Katalyse e.V. , Albert Einstein Straße 29a, 18059 Rostock, Germany
| | - Steffen Fischer
- Institut für Chemie, Universität Rostock , Dr.-Lorenz-Weg 1, 18059 Rostock, Germany
| | - Haijun Jiao
- Leibniz-Institut für Katalyse e.V. , Albert Einstein Straße 29a, 18059 Rostock, Germany
| | - Anke Spannenberg
- Leibniz-Institut für Katalyse e.V. , Albert Einstein Straße 29a, 18059 Rostock, Germany
| | - Wolfgang Baumann
- Leibniz-Institut für Katalyse e.V. , Albert Einstein Straße 29a, 18059 Rostock, Germany
| | - Ralf Ludwig
- Institut für Chemie, Universität Rostock , Dr.-Lorenz-Weg 1, 18059 Rostock, Germany
| | - Kathrin Junge
- Leibniz-Institut für Katalyse e.V. , Albert Einstein Straße 29a, 18059 Rostock, Germany
| | - Matthias Beller
- Leibniz-Institut für Katalyse e.V. , Albert Einstein Straße 29a, 18059 Rostock, Germany
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Tondreau AM, Boncella JM. 1,2-Addition of Formic or Oxalic Acid to –N{CH2CH2(PiPr2)}2-Supported Mn(I) Dicarbonyl Complexes and the Manganese-Mediated Decomposition of Formic Acid. Organometallics 2016. [DOI: 10.1021/acs.organomet.6b00274] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Aaron M. Tondreau
- Chemistry Division, Los Alamos National Laboratory, MS J514, Los Alamos, New Mexico 87545, United States
| | - James M. Boncella
- Chemistry Division, Los Alamos National Laboratory, MS J514, Los Alamos, New Mexico 87545, United States
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Batke S, Kothe T, Haas M, Wadepohl H, Ballmann J. Diamidophosphines with six-membered chelates and their coordination chemistry with group 4 metals: development of a trimethylene-methane-tethered [PN2]-type "molecular claw". Dalton Trans 2016; 45:3528-40. [PMID: 26804587 DOI: 10.1039/c5dt04911c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The coordination chemistry of the phosphine-tethered diamidophosphine ligands PhP(CH2CH2CH2NHPh)2 (pr[NPN]H2) and PhP(1,2-CH2-C6H4-NHSiMe3)2 (bn[NPN]H2) featuring six-membered N–C3–P chelates was explored with group 4 metals, which allowed for the consecutive development of a new trimethylene-methane-tethered [PN2] scaffold. In the case of the propylene-linked system pr[NPN]H2, access to the sparingly soluble dibenzyl derivative pr[NPN]ZrBn2 (3-Zr) was gained, while thermally sensitive zirconium and hafnium diiodo complexes bn[NPN]MI2 (5-M, M = Zr, Hf) were isolated in the case of the benzylene-linked derivative bn[NPN]H2. Despite the related phosphine-tethered backbone architectures of both of these ligands, their group 4 complexes were found to exhibit either C1-symmetric (bn[NPN]MX2) or averaged CS-symmetric (pr[NPN]MX2) structures in solution. To restrain the overall flexibility of these systems and thereby control the properties of the resulting complexes without disrupting the six-membered chelates, the new trimethylene-methane-tethered N,N′-di-(tert-butyl)-substituted [PN2]H2 protioligand was designed. This tripodal ligand system was prepared on a gram scale and its CS-symmetric dichloro complexes [PN2]MCl2 (6-M, M = Ti, Zr, Hf) were isolated subsequently. The benzene-soluble dibenzyl derivative [PN2]ZrBn2 (7-Zr) was synthesised as well and characterised by X-ray diffraction. These results are discussed not only in conjunction with the known [NPN]-coordinated group 4 complexes incorporating five-membered chelates, but also in the context of “molecular claws” that are related to the new [PN2] tripod.
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Affiliation(s)
- S Batke
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany.
| | - T Kothe
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany.
| | - M Haas
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany.
| | - H Wadepohl
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany.
| | - J Ballmann
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany.
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Liang LC, Chou KW, Su WJ, Chen HS, Hsu YL. Homo- and Heteropolynuclear Clusters of Phosphine Triphenolates. Inorg Chem 2015; 54:11526-34. [PMID: 26587884 DOI: 10.1021/acs.inorgchem.5b02208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synthesis and structural characterization of a series of homo- and heteropolynuclear clusters constructed with a potentially tetradentate phosphine triphenolate ligand are presented. Treatment of tris(3,5-di-tert-butyl-2-hydroxyphenyl)phosphine (H3[O3P]) with 3 equiv of nBuLi in diethyl ether at -35 °C affords hexanuclear Li6[O3P]2(OEt2)2 (1) as colorless crystals. In situ lithiation of H3[O3P] with 3 equiv of nBuLi in THF at -35 °C followed by metathetical reactions with MnCl2 or NiCl2(DME) gives crystals of forest green pentanuclear MnLi4[O3P]2(THF)3 (2) or dark brown tetranuclear Ni2Li2[O3P]2(THF)2 (3), respectively. Alkane elimination of ZnR2 (R = Me, Et) with H3[O3P] in THF at 25 °C generates high yields of colorless crystalline trinuclear Zn3[O3P]2(THF)2 (4). The cluster structures of 1-4 were all determined by single crystal X-ray diffraction studies. These molecules represent the first examples of metal complexes supported by phosphine triphenolate derivatives. The cluster 2 contains a paramagnetic core of high spin Mn(II) (S = 5/2) as indicated by solution and solid state magnetic susceptibility measurements.
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Affiliation(s)
- Lan-Chang Liang
- Department of Chemistry and Center for Nanoscience & Nanotechnology, National Sun Yat-sen University , Kaohsiung 80424, Taiwan.,Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , Kaohsiung 80708, Taiwan
| | - Kuan-Wei Chou
- Department of Chemistry and Center for Nanoscience & Nanotechnology, National Sun Yat-sen University , Kaohsiung 80424, Taiwan
| | - Wei-Jia Su
- Department of Chemistry and Center for Nanoscience & Nanotechnology, National Sun Yat-sen University , Kaohsiung 80424, Taiwan
| | - Han-Sheng Chen
- Department of Chemistry and Center for Nanoscience & Nanotechnology, National Sun Yat-sen University , Kaohsiung 80424, Taiwan
| | - Yu-Lin Hsu
- Department of Chemistry and Center for Nanoscience & Nanotechnology, National Sun Yat-sen University , Kaohsiung 80424, Taiwan
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Hewage JS, Wanniarachchi S, Morin TJ, Liddle BJ, Banaszynski M, Lindeman SV, Bennett B, Gardinier JR. Homoleptic nickel(II) complexes of redox-tunable pincer-type ligands. Inorg Chem 2014; 53:10070-84. [PMID: 25222027 PMCID: PMC5047063 DOI: 10.1021/ic500657e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Different synthetic methods have been developed to prepare eight new redox-active pincer-type ligands, H(X,Y), that have pyrazol-1-yl flanking donors attached to an ortho-position of each ring of a diarylamine anchor and that have different groups, X and Y, at the para-aryl positions. Together with four previously known H(X,Y) ligands, a series of 12 Ni(X,Y)2 complexes were prepared in high yields by a simple one-pot reaction. Six of the 12 derivatives were characterized by single-crystal X-ray diffraction, which showed tetragonally distorted hexacoordinate nickel(II) centers. The nickel(II) complexes exhibit two quasi-reversible one-electron oxidation waves in their cyclic voltammograms, with half-wave potentials that varied over a remarkable 700 mV range with the average of the Hammett σ(p) parameters of the para-aryl X, Y groups. The one- and two-electron oxidized derivatives [Ni(Me,Me)2](BF4)n (n = 1, 2) were prepared synthetically, were characterized by X-band EPR, electronic spectroscopy, and single-crystal X-ray diffraction (for n = 2), and were studied computationally by DFT methods. The dioxidized complex, [Ni(Me,Me)2](BF4)2, is an S = 2 species, with nickel(II) bound to two ligand radicals. The mono-oxidized complex [Ni(Me,Me)2](BF4), prepared by comproportionation, is best described as nickel(II) with one ligand centered radical. Neither the mono- nor the dioxidized derivative shows any substantial electronic coupling between the metal and their bound ligand radicals because of the orthogonal nature of their magnetic orbitals. On the other hand, weak electronic communication occurs between ligands in the mono-oxidized complex as evident from the intervalence charge transfer (IVCT) transition found in the near-IR absorption spectrum. Band shape analysis of the IVCT transition allowed comparisons of the strength of the electronic interaction with that in the related, previously known, Robin-Day class II mixed valence complex, [Ga(Me,Me)2](2+).
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Affiliation(s)
- Jeewantha S. Hewage
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
| | - Sarath Wanniarachchi
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
| | - Tyler J. Morin
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
| | - Brendan J. Liddle
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
| | - Megan Banaszynski
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
| | - Sergey V. Lindeman
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
| | - Brian Bennett
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, United States
| | - James R. Gardinier
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
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Smith DA, Herbert DE, Walensky JR, Ozerov OV. Monomeric Rhodium(II) Complexes Supported by a Diarylamido/Bis(phosphine) PNP Pincer Ligand and Their Reactivity Toward Dihydrogen. Organometallics 2013. [DOI: 10.1021/om300760j] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Dan A. Smith
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77842, United States
| | - David E. Herbert
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77842, United States
| | - Justin R. Walensky
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Oleg V. Ozerov
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77842, United States
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22
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Ivanova A, Romanova J, Tadjer A, Baumgarten M. Magnetostructural correlation for rational design of Mn(II) hybrid-spin complexes. J Phys Chem A 2013; 117:670-8. [PMID: 23256643 DOI: 10.1021/jp312258j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The magnetic properties of a series of manganese(II) diacetylacetonate and dihexafluoroacetylacetonate hybrid-spin complexes with neutral pyridine-based organic radicals were characterized theoretically by DFT calculations. Three stable radicals, in which a radical group is bound in either para or meta position with respect to the pyridine nitrogen atom, were considered. The correct stable structures and multiplets of the complexes were obtained by full geometry optimization starting from an ideal structure. A total of three important geometry descriptors of the complexes were monitored and related to their magnetic characteristics. These structural parameters are (i) the torsion angle governing the conjugation of the organic radical m-PyNO (anti versus gauche), (ii) the coordination geometry of the acetyl acetonate ligands around the metal ion (square versus rhombic), and (iii) the relative orientation of the organic radical with respect to the acetyl acetonate plane (parallel versus perpendicular). It was found that the magnetic properties are not sensitive to the orientation of the radicals with respect to the equatorial plane but do depend on the conformation of the organic radicals. Even a spin switch between the ferromagnetic (S = (7)/(2)) and antiferromagnetic (S = (3)/(2)) ground state was found to be feasible for one of the complexes upon variation of the organic radical geometry, namely, the dihedral angle between the organic radical moiety and the pyridine ring. The pattern of molecular orbital overlap was determined to be the key factor governing the exchange coupling in the modeled systems. Bonding π-type overlap provides antiferromagnetic coupling in all complexes of the para radicals. In the meta analogues, the spins are coupled through the σ orbitals. A low-spin ground state occurs whenever a continuous σ-overlap pathway is present in the complex. Ferromagnetic interaction requires σ-π orthogonality of the pyridine atomic orbitals and/or π-antibonding Mn-pyridine natural orbital overlap. Using an estimate of the donor-acceptor energy stabilization, the affinity of a given Mn(II) d-orbital to mix with the sp(2) orbital from pyridine can be predicted.
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Affiliation(s)
- Anela Ivanova
- Department of Physical Chemistry, Faculty of Chemistry and Pharmacy, University of Sofia, 1 James Bourchier Avenue, 1164 Sofia, Bulgaria.
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23
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Harford PJ, Wheatley AEH. Alkali/coinage metals – organolithium, organocuprate chemistry. ORGANOMETALLIC CHEMISTRY 2012. [DOI: 10.1039/9781849734868-00091] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Part 1 of this chapter reviews coordination compounds of the alkali metals that contain a carbon-metal bond, looking firstly at organolithiums involving simple silanes. The use of aryl, alkynyl and N-donor ligands is also discussed. Compounds of the coinage metals - copper, silver and gold - are discussed in Part 2 of the review. Discussion is broken down by metal, with copper being considered first. Compounds containing, among others, alkene, amido and phosphido ligands are discussed, along with the significant amount of work on carbene complexes. This interest in carbene complexes is also noted within the silver and gold sections that follow, with a large number of new compounds being described. Polymeric chains and networks containing silver centres have attracted considerable interest and are described, along with the luminescent properties of a selection of novel gold species. This part of the review is completed by coverage of mixed-coinage metal structures, where the systems are found to display luminescent properties. Here again, the compounds discussed contain at least one carbon-metal bond.
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Affiliation(s)
- Philip J. Harford
- Department of Chemistry University of Cambridge, Lensfield Road, Cambridge, CB2 1EW U.K
| | - Andrew E. H. Wheatley
- Department of Chemistry University of Cambridge, Lensfield Road, Cambridge, CB2 1EW U.K
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24
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DeMott JC, Surawatanawong P, Barnett SM, Chen CH, Foxman BM, Ozerov OV. Experimental and computational exploration of the dynamic behavior of (PNP)BF2, a boron compound supported by an amido/bis(phosphine) pincer ligand. Dalton Trans 2011; 40:11562-70. [PMID: 21956286 DOI: 10.1039/c1dt11172h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The diarylamido/bis(phosphine) PNP pincer ligand (2-(i)Pr(2)P-4-MeC(6)H(3))(2)N has been evaluated as a scaffold for supporting a BF(2) fragment. Compound (PNP)BF(2) (6) was prepared by simple metathesis of (PNP)Li (5) with Me(2)SBF(3). NMR spectra of 6 in solution are of apparent C(2) symmetry, suggestive of a symmetric environment about boron. However, a combination of X-ray structural studies, low-temperature NMR investigations, and DFT calculations consistently establish that the ground state of this molecule contains a classical four-coordinate boron with a PNBF(2) coordination environment, with one phosphine donor in PNP remaining "free". Fortuitous formation of a single crystal of (PNP)BF(2)·HBF(4) (7), in which the "free" phosphine is protonated, furnished another structure containing the same PNBF(2) environment about boron for comparison and the two PNBF(2) environments in 6 and 7 are virtually identical. DFT studies on several other diarylamido/bis(phosphine) pincer (PNP)BF(2) systems were carried out and all displayed a similar four coordinate PNBF(2) environment in the ground state structures. The symmetric appearance of the room-temperature NMR spectra is explained by the rapid interconversion between two degenerate four-coordinate, C(1)-symmetric ground-state forms. Lineshape analysis of the (1)H and (19)F NMR spectra over a temperature range of 180-243 K yielded the activation parameters ΔH(‡) = 8.1(3) kcal mol(-1) and ΔS(‡) = -6.0(15) eu, which are broadly consistent with the calculated values. Calculations indicate that the exchange of phosphine donors at the boron center proceeds by an intrinsically dissociative mechanism.
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Affiliation(s)
- Jessica C DeMott
- Department of Chemistry, Texas A&M University, College Station, TX 77843-3255, USA
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