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Bedbur K, Stucke N, Liehrs L, Krahmer J, Tuczek F. Catalytic Ammonia Synthesis Mediated by Molybdenum Complexes with PN 3P Pincer Ligands: Influence of P/N Substituents and Molecular Mechanism. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27227843. [PMID: 36431964 PMCID: PMC9692791 DOI: 10.3390/molecules27227843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 11/08/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022]
Abstract
Three molybdenum trihalogenido complexes supported by different PN3P pincer ligands were synthesized and investigated regarding their activity towards catalytic N2-to-NH3 conversion. The highest yields were obtained with the H-PN3PtBu ligand. The corresponding Mo(V)-nitrido complex also shows good catalytic activity. Experiments regarding the formation of the analogous Mo(IV)-nitrido complex lead to the conclusion that the mechanism of catalytic ammonia formation mediated by the title systems does not involve N-N cleavage of a dinuclear Mo-dinitrogen complex, but follows the classic Chatt cycle.
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2
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Brown J, Ovens J, Richeson D. Elucidating Two Distinct Pathways for Electrocatalytic Hydrogen Production Using Co II Pincer Complexes. CHEMSUSCHEM 2022; 15:e202102542. [PMID: 35041773 DOI: 10.1002/cssc.202102542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/02/2022] [Indexed: 06/14/2023]
Abstract
Hydrogen gas is a sustainable energy source with water as the sole combustion product. As a result, efforts to catalyze H2 production are pertinent and widespread. The electrocatalytic H2 generating capabilities of two CoII complexes, [Co(κ3 -2,6-{Ph2 PNR}2 (NC5 H3 ))Br2 ] with R=H (I) or R=Me (II), were presented for a variety of proton sources including trifluoroacetic acid (TFA), acetic acid (AA), and trifluoroethanol (TFE). Cyclic voltammetry and controlled potential coulometry demonstrated that electrocatalysis from I and II occurred at two different potentials and are associated with different reduction processes. Density functional theory analysis provided insight into the identities of the catalyst and supported two distinct reaction pathways for electrocatalytic proton reduction. Specifically, stronger acids (e. g., AA, TFA) proceeded at -1.31 to -1.45 V through a MI /MIII pathway while sources with higher pKa values (e. g., TFE, H2 O) generated hydrogen at -2.4 V via M0 /MII ligand-assisted metal-centered reduction.
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Affiliation(s)
- Josh Brown
- Department of Chemistry and Biomolecular Sciences Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, ON K1 N 6 N5, Canada
| | - Jeffrey Ovens
- Department of Chemistry and Biomolecular Sciences Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, ON K1 N 6 N5, Canada
| | - Darrin Richeson
- Department of Chemistry and Biomolecular Sciences Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, ON K1 N 6 N5, Canada
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3
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Vielhaber T, Faust K, Topf C. Group 6 Metal Carbonyl Complexes Supported by a Bidentate PN Ligand: Syntheses, Characterization, and Catalytic Hydrogenation Activity. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00612] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Thomas Vielhaber
- Institute of Catalysis (INCA), Johannes Kepler University (JKU), 4040 Linz, Austria
| | - Kirill Faust
- Institute of Catalysis (INCA), Johannes Kepler University (JKU), 4040 Linz, Austria
| | - Christoph Topf
- Institute of Catalysis (INCA), Johannes Kepler University (JKU), 4040 Linz, Austria
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4
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Leischner T, Spannenberg A, Junge K, Beller M. Synthesis of Molybdenum Pincer Complexes and Their Application in the Catalytic Hydrogenation of Nitriles. ChemCatChem 2020. [DOI: 10.1002/cctc.202000736] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Thomas Leischner
- Leibniz Institute for Catalysis Albert-Einstein-Straße 29a 18059 Rostock Germany
| | - Anke Spannenberg
- Leibniz Institute for Catalysis Albert-Einstein-Straße 29a 18059 Rostock Germany
| | - Kathrin Junge
- Leibniz Institute for Catalysis Albert-Einstein-Straße 29a 18059 Rostock Germany
| | - Matthias Beller
- Leibniz Institute for Catalysis Albert-Einstein-Straße 29a 18059 Rostock Germany
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5
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Stucke N, Krahmer J, Näther C, Tuczek F. Molybdenum Complexes Supported by PN3
P Pincer Ligands: Synthesis, Characterization, and Application to Synthetic Nitrogen Fixation. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201801194] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Nadja Stucke
- Institute of Inorganic Chemistry; Christian Albrechts University Kiel; Max-Eyth-Strasse 2 24118 Kiel Germany
| | - Jan Krahmer
- Institute of Inorganic Chemistry; Christian Albrechts University Kiel; Max-Eyth-Strasse 2 24118 Kiel Germany
| | - Christian Näther
- Institute of Inorganic Chemistry; Christian Albrechts University Kiel; Max-Eyth-Strasse 2 24118 Kiel Germany
| | - Felix Tuczek
- Institute of Inorganic Chemistry; Christian Albrechts University Kiel; Max-Eyth-Strasse 2 24118 Kiel Germany
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6
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de Aguiar SRMM, Schröder-Holzhacker C, Pecak J, Stöger B, Kirchner K. Synthesis and characterization of TADDOL-based chiral group six PNP pincer tricarbonyl complexes. MONATSHEFTE FUR CHEMIE 2018; 150:103-109. [PMID: 30662092 PMCID: PMC6320742 DOI: 10.1007/s00706-018-2281-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Accepted: 08/14/2018] [Indexed: 11/27/2022]
Abstract
ABSTRACT The new chiral PNP pincer ligand N 2,N 6-bis((3aR, 8aR)-2,2-dimethyl-4,4,8,8-tetraphenyltetrahydro[1,3]dioxolo[4,5-e][1,3,2]dioxaphosphepin-6-yl)pyridine-2,6-diamine (PNP-TADDOL) was synthesized in 80% isolated yield. Complexes of the type [M(PNP-TADDOL)(CO)3] (M = Cr, Mo, and W) were prepared via a solvothermal approach. This methodology constitutes a fast, simple, and practical synthetic method to obtain complexes of that type in high isolated yields. The X-ray structure of the molybdenum complex is presented. GRAPHICAL ABSTRACT
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Affiliation(s)
- Sara R. M. M. de Aguiar
- Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria
| | | | - Jan Pecak
- Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria
| | - Berthold Stöger
- X-ray Center, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria
| | - Karl Kirchner
- Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria
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7
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Leischner T, Spannenberg A, Junge K, Beller M. Molecular Defined Molybdenum–Pincer Complexes and Their Application in Catalytic Hydrogenations. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00410] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Thomas Leischner
- Leibniz Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Anke Spannenberg
- Leibniz Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Kathrin Junge
- Leibniz Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Matthias Beller
- Leibniz Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock, Germany
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8
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Schlimm A, Stucke N, Flöser BM, Rusch T, Krahmer J, Näther C, Strunskus T, Magnussen OM, Tuczek F. Influence of a Metal Substrate on Small-Molecule Activation Mediated by a Surface-Adsorbed Complex. Chemistry 2018; 24:10732-10744. [DOI: 10.1002/chem.201800911] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/29/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Alexander Schlimm
- Institute of Inorganic Chemistry; Christian Albrechts University Kiel; Max-Eyth-Strasse 2 24118 Kiel Germany
| | - Nadja Stucke
- Institute of Inorganic Chemistry; Christian Albrechts University Kiel; Max-Eyth-Strasse 2 24118 Kiel Germany
| | - Benedikt M. Flöser
- Institute of Inorganic Chemistry; Christian Albrechts University Kiel; Max-Eyth-Strasse 2 24118 Kiel Germany
| | - Talina Rusch
- Institute of Experimental and Applied Physics; Christian Albrechts University Kiel; Leibnizstrasse 19 24118 Kiel Germany
| | - Jan Krahmer
- Institute of Inorganic Chemistry; Christian Albrechts University Kiel; Max-Eyth-Strasse 2 24118 Kiel Germany
| | - Christian Näther
- Institute of Inorganic Chemistry; Christian Albrechts University Kiel; Max-Eyth-Strasse 2 24118 Kiel Germany
| | - Thomas Strunskus
- Institute for Materials Science-Multicomponent Materials; Christian Albrechts University Kiel; Kaiserstrasse 2 24143 Kiel Germany
| | - Olaf M. Magnussen
- Institute of Experimental and Applied Physics; Christian Albrechts University Kiel; Leibnizstrasse 19 24118 Kiel Germany
| | - Felix Tuczek
- Institute of Inorganic Chemistry; Christian Albrechts University Kiel; Max-Eyth-Strasse 2 24118 Kiel Germany
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9
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Employing a neutral “PN3P” pincer to access mer-Re(I) tricarbonyl complexes: Autoionization of a halo ligand and the role of an N-R (R = H, Me) substituent. Polyhedron 2018. [DOI: 10.1016/j.poly.2017.08.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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10
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11
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Rao GK, Pell W, Gabidullin B, Korobkov I, Richeson D. Electro- and Photocatalytic Generation of H 2 Using a Distinctive Co II "PN 3 P" Pincer Supported Complex with Water or Saturated Saline as a Hydrogen Source. Chemistry 2017; 23:16763-16767. [PMID: 29044839 DOI: 10.1002/chem.201704882] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Indexed: 12/18/2022]
Abstract
Efficient electrocatalytic production of H2 from mixed water/acetonitrile solutions was achieved using three new CoII complexes supported by the neutral pincer ligand bis(diphenylphosphino)-2,6-di(methylamino)pyridine ("PN3 P"). At -1.9 V vs. Fc/Fc+ , these catalysts showed 96 % Faradaic efficiency with added water or saturated aqueous saline at rates of up to 316 L(mol cat)-1 (cm2 )-1 h-1 using a glassy carbon working electrode. The complex [Co(κ3 -2,6-{Ph2 PNMe}2 (NC5 H3 )Br2 ] (1) was also able to photocatalytically reduce water to hydrogen in the presence of a Ru(bpy)32+ photosensitizer and a reductant.
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Affiliation(s)
- Gyandshwar Kumar Rao
- Department of Chemistry and Biomolecular Science, Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, ON, K1N 6N5, USA
| | - Wendy Pell
- Department of Chemistry and Biomolecular Science, Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, ON, K1N 6N5, USA
| | - Bulat Gabidullin
- Department of Chemistry and Biomolecular Science, Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, ON, K1N 6N5, USA
| | - Ilia Korobkov
- Department of Chemistry and Biomolecular Science, Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, ON, K1N 6N5, USA
| | - Darrin Richeson
- Department of Chemistry and Biomolecular Science, Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, ON, K1N 6N5, USA
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12
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Freitag F, Irrgang T, Kempe R. Cobalt-Catalyzed Alkylation of Secondary Alcohols with Primary Alcohols via Borrowing Hydrogen/Hydrogen Autotransfer. Chemistry 2017; 23:12110-12113. [PMID: 28452422 DOI: 10.1002/chem.201701211] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Indexed: 01/11/2023]
Abstract
Alcohols are promising sustainable starting materials because they can be obtained from abundant and indigestible biomass. The substitution of expensive noble metals in catalysis by earth abundant 3d metals, such as Mn, Fe, or Co, (nonprecious or base metals) is a related key concept with respect to sustainability. Here, we report on the first cobalt-catalyzed alkylation of secondary alcohols with primary alcohols. Easy-to-synthesize and easy-to-activate PN5 P-pincer-ligand-stabilized Co complexes developed in our laboratory mediate the reaction most efficiently. The catalysis is applicable to a broad substrate scope and proceeds under relatively mild conditions. We have even demonstrated the coupling of a variety of purely aliphatic alcohols with a base or nonprecious metal catalyst. Mechanistic studies indicate that the reaction follows the borrowing hydrogen or hydrogen autotransfer concept.
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Affiliation(s)
- Frederik Freitag
- Anorganische Chemie II-Katalysatordesign, Universität Bayreuth, 95540, Bayreuth, Germany
| | - Torsten Irrgang
- Anorganische Chemie II-Katalysatordesign, Universität Bayreuth, 95540, Bayreuth, Germany
| | - Rhett Kempe
- Anorganische Chemie II-Katalysatordesign, Universität Bayreuth, 95540, Bayreuth, Germany
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13
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de Aguiar SRMM, Stöger B, Pittenauer E, Allmaier G, Veiros LF, Kirchner K. Structural diversity of halocarbonyl molybdenum and tungsten PNP pincer complexes through ligand modifications. Dalton Trans 2016; 45:13834-45. [PMID: 27513832 PMCID: PMC5048400 DOI: 10.1039/c6dt02251k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 07/18/2016] [Indexed: 11/21/2022]
Abstract
This work presents a comparative study of a series of halocarbonyl Mo(ii) and W(ii) complexes of the types [M(PNP)(CO)3X]X and [M(PNP)(CO)2X2] (M = Mo, W; X = I, Br), featuring PNP pincer ligands based on a 2,6-diaminopyridine scaffold. The complexes were prepared and fully characterized. The syntheses of these complexes were accomplished by treatment of [M(PNP)(CO)3] with stoichiometric amounts of I2 and Br2, respectively. The modification of the 2,6-diaminopyridine scaffold by introducing NMe and NPh instead of NH spacers with concomitant modification of the phosphine moieties changed the steric and electronic properties of the PNP ligand significantly. While in the case of NH linkers exclusively cationic seven-coordinate complexes of the type [M(PNP)(CO)3X](+) were obtained with NMe and NPh spacers neutral seven-coordinate complexes of the type [M(PNP)(CO)2X2] were afforded. In the case of the latter, when the reaction is performed in the presence of CO also [M(PNP)(CO)3X](+) complexes are formed which slowly lose CO to give [M(PNP)(CO)2X2]. The halocarbonyl tungsten chemistry parallels that of molybdenum. The only exception is molybdenum in conjunction with the PNP(Me)-iPr ligand, where the coordinatively unsaturated complex [Mo(PNP(Me)-iPr)(CO)X2] is formed. DFT mechanistic studies reveal that the seven-coordinate complexes should be the thermodynamic as well as the kinetic products. Since [Mo(PNP(Me)-iPr)(CO)X2] is the observed product it suggests that the reaction follows an alternative path. Structures of representative complexes were determined by X-ray single crystal analyses.
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Affiliation(s)
- Sara R. M. M. de Aguiar
- Institute of Applied Synthetic Chemistry , Vienna University of Technology , Getreidemarkt 9 , A-1060 Vienna , Austria .
| | - Berthold Stöger
- Institute of Chemical Technologies and Analytics , Vienna University of Technology , Getreidemarkt 9 , A-1060 Vienna , Austria
| | - Ernst Pittenauer
- Institute of Chemical Technologies and Analytics , Vienna University of Technology , Getreidemarkt 9 , A-1060 Vienna , Austria
| | - Günter Allmaier
- Institute of Chemical Technologies and Analytics , Vienna University of Technology , Getreidemarkt 9 , A-1060 Vienna , Austria
| | - Luis F. Veiros
- Centro de Química Estrutural , Instituto Superior Técnico , Universidade de Lisboa , Av. Rovisco Pais No. 1 , 1049-001 Lisboa , Portugal
| | - Karl Kirchner
- Institute of Applied Synthetic Chemistry , Vienna University of Technology , Getreidemarkt 9 , A-1060 Vienna , Austria .
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14
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Deibl N, Kempe R. General and Mild Cobalt-Catalyzed C-Alkylation of Unactivated Amides and Esters with Alcohols. J Am Chem Soc 2016; 138:10786-9. [PMID: 27490682 DOI: 10.1021/jacs.6b06448] [Citation(s) in RCA: 172] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The borrowing hydrogen or hydrogen autotransfer methodology is an elegant and sustainable or green concept to construct carbon-carbon bonds. In this concept, alcohols, which can be obtained from barely used and indigestible biomass, such as lignocellulose, are employed as alkylating reagents. An especially challenging alkylation is that of unactivated esters and amides. Only noble metal catalysts based on iridium and ruthenium have been used to accomplish these reactions. Herein, we report on the first base metal-catalyzed α-alkylation of unactivated amides and esters by alcohols. Cobalt complexes stabilized with pincer ligands, recently developed in our laboratory, catalyze these reactions very efficiently. The precatalysts can be synthesized easily from commercially available starting materials on a multigram scale and are self-activating under the basic reaction conditions. This Co catalyst class is also able to mediate alkylation reactions of both esters and amides. In addition, we apply the methodology to synthesize ketones and to convert alcohols into aldehydes elongated by two carbon atoms.
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Affiliation(s)
- Nicklas Deibl
- Inorganic Chemistry II, Catalyst Design, Universität Bayreuth , 95440 Bayreuth, Germany
| | - Rhett Kempe
- Inorganic Chemistry II, Catalyst Design, Universität Bayreuth , 95440 Bayreuth, Germany
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15
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Rao GK, Pell W, Korobkov I, Richeson D. Electrocatalytic reduction of CO2 using Mn complexes with unconventional coordination environments. Chem Commun (Camb) 2016; 52:8010-3. [PMID: 27264057 DOI: 10.1039/c6cc03827a] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New complexes, Mn{κ(3)-[2,6-{Ph2PNMe}2(NC5H3)]}(CO)3(+)Br(-) (1(+)Br(-)) and MnBr{κ(2)-(Ph2P)NMe(NC5H4)}(CO)3 (2), are reported and present new ligand environments for CO2 electrocatalytic reduction to CO. Compound 1(+) presents a unique metal geometry for CO production (96%) in the absence of added water while 2 required addition of water and generated both CO and H2 products.
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Affiliation(s)
- Gyandshwar Kumar Rao
- Department of Chemistry and Biomolecular Sciences and the Center for Catalysis and Research Innovation, University of Ottawa, 10 Marie Curie, Ottawa, ON K1N6N5, Canada.
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16
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Mota Merelo de Aguiar SR, Stöger B, Weil M, Kirchner K. Tetrakis(μ2-diphenylphosphinato-κ2O,O′)tetra-μ3-oxido-tetraoxidohexamolybdenum(V). IUCRDATA 2016. [DOI: 10.1107/s2414314616000365] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The molecule of the title compound, [Mo4(μ2-C12H10OP2)4(μ3-O)4O4], exhibits point group symmetry 2 with the twofold rotation axis passing through two opposite P atoms. Each MoVatom is bridged by three O atoms resulting in an Mo4O4heterocubane core. In the crystal, weak C—H...O interactions may help to consolidate packing of the molecules.
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17
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Mastalir M, de Aguiar SRMM, Glatz M, Stöger B, Kirchner K. A Convenient Solvothermal Synthesis of Group 6 PNP Pincer Tricarbonyl Complexes. Organometallics 2016. [DOI: 10.1021/acs.organomet.5b00940] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Matthias Mastalir
- Institute of Applied
Synthetic Chemistry and ‡Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
| | - Sara R. M. M. de Aguiar
- Institute of Applied
Synthetic Chemistry and ‡Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
| | - Mathias Glatz
- Institute of Applied
Synthetic Chemistry and ‡Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
| | - Berthold Stöger
- Institute of Applied
Synthetic Chemistry and ‡Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
| | - Karl Kirchner
- Institute of Applied
Synthetic Chemistry and ‡Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
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18
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Rao GK, Gorelsky SI, Korobkov I, Richeson D. Coinage metal complexes supported by a "PN(3)P" scaffold. Dalton Trans 2015; 44:19153-62. [PMID: 26485392 DOI: 10.1039/c5dt03515e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A series of monovalent group 11 complexes, [2,6-{Ph2PNMe}2(NC5H3)]CuBr 1, [2,6-{Ph2PNMe}2(NC5H3)]CuOTf 2, [2,6-{Ph2PNMe}2(NC5H3)]AgOTf 3, and [2,6-{Ph2PNMe}2(NC5H3)](AuCl)24, supported by a neutral PN(3)P ligand have been synthesized and characterized by multinuclear NMR and single crystal X-ray diffraction studies. The variation of the coordination properties were analyzed and electronic structure calculations have been carried out to provide insight on the bonding details in these complexes. The Cu(I) complexes displayed an unusual coordination geometry with a tridentate pincer ligand and an overall four coordinate trigonal pyramidal geometry. In contrast the Ag(I) analogue displayed a bidentate κ(2)-P,P' ligation leaving the pyridyl-N atom uncoordinated and yielding a pyramidalized trigonal planar geometry around Ag. The bimetallic Au(I) complex completed the series and displayed a monodentate P-bonded ligand and a linear coordination geometry.
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Affiliation(s)
- Gyandshwar Kumar Rao
- Center for Catalysis Research and Innovation and Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
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19
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Rösler S, Ertl M, Irrgang T, Kempe R. Cobalt-Catalyzed Alkylation of Aromatic Amines by Alcohols. Angew Chem Int Ed Engl 2015; 54:15046-50. [DOI: 10.1002/anie.201507955] [Citation(s) in RCA: 253] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Indexed: 12/13/2022]
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Rösler S, Ertl M, Irrgang T, Kempe R. Cobalt-katalysierte Alkylierung von aromatischen Aminen durch Alkohole. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201507955] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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21
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de Aguiar SRMM, Öztopcu Ö, Stöger B, Mereiter K, Veiros LF, Pittenauer E, Allmaier G, Kirchner K. Synthesis and reactivity of coordinatively unsaturated halocarbonyl molybdenum PNP pincer complexes. Dalton Trans 2015; 43:14669-79. [PMID: 25142749 DOI: 10.1039/c4dt01932f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the present study a series of six-coordinate neutral 16e halocarbonyl Mo(ii) complexes of the type [Mo(PNP(Me)-iPr)(CO)X2] (X = I, Br, Cl), featuring the PNP pincer ligand N,N'-bis(diisopropylphosphino)-N,N'-dimethyl-2,6-diaminopyridine (PNP(Me)-iPr), were prepared and fully characterized. The synthesis of these complexes was accomplished by different methodologies depending on the halide ligands. For X = I and Br, [Mo(PNP(Me)-iPr)(CO)I2] and [Mo(PNP(Me)-iPr)(CO)Br2] were obtained by reacting [Mo(PNP(Me)-iPr)(CO)3] with stoichiometric amounts of I2 and Br2, respectively. In the case of X = Cl, [Mo(PNP(Me)-iPr)(CO)Cl2] was afforded by the reaction of [Mo(CO)4(μ-Cl)Cl]2 with 1 equiv. of PNP(Me)-iPr. The equivalent procedure also worked for X = Br. The modification of the 2,6-diaminopyridine scaffold by introducing NMe instead of NH spacers between the aromatic pyridine ring and the phosphine moieties changed the steric properties of the PNP-iPr ligand significantly. While in the present case exclusively neutral six-coordinate complexes of the type [Mo(PNP(Me)-iPr)(CO)X2] were obtained, with the parent PNP-iPr ligand, i.e. featuring NH spacers, cationic seven-coordinate complexes of the type [Mo(PNP-iPr)(CO)3X]X were afforded. Upon treatment of [Mo(PNP(Me)-iPr)(CO)X2] (X = Br, Cl) with Ag(+) in CH3CN, the cationic complexes [Mo(PNP(Me)-iPr)(CO)(CH3CN)X](+) were formed. Halide abstraction from [Mo(PNP(Me)-iPr)(CO)Cl2] in THF-CH2Cl2 afforded [Mo(PNP(Me)-iPr)(CO)(THF)Cl](+). In keeping with the facile synthesis of monocationic complexes preliminary ESI-MS and DFT/B3LYP studies revealed that one halide ligand in complexes [Mo(PNP(Me)-iPr)(CO)X2] is labile forming cationic fragments [Mo(PNP(Me)-iPr)(CO)X](+) which react with molecular oxygen in parallel pathways to yield mono and dioxo Mo(iv) and Mo(vi) species. Structures of representative complexes were determined by X-ray single crystal analyses.
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Affiliation(s)
- Sara R M M de Aguiar
- Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria.
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Glatz M, Bichler B, Mastalir M, Stöger B, Weil M, Mereiter K, Pittenauer E, Allmaier G, Veiros LF, Kirchner K. Iron(ii) complexes featuring κ3- and κ2-bound PNP pincer ligands – the significance of sterics. Dalton Trans 2015; 44:281-94. [PMID: 25376759 DOI: 10.1039/c4dt02866j] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of octahedral Fe(ii) complexes of the type [Fe(κ3-P,N,P-PNP)(κ2-P,N-PNP)X]+ (X = Cl, Br) where PNP pincer ligands are coordinated both in a κ3-P,N,P- and κ2-P,N-fashion was prepared and characterized.
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Affiliation(s)
- Mathias Glatz
- Institute of Applied Synthetic Chemistry
- Vienna University of Technology
- A-1060 Vienna
- Austria
| | - Bernhard Bichler
- Institute of Applied Synthetic Chemistry
- Vienna University of Technology
- A-1060 Vienna
- Austria
| | - Matthias Mastalir
- Institute of Applied Synthetic Chemistry
- Vienna University of Technology
- A-1060 Vienna
- Austria
| | - Berthold Stöger
- Institute of Chemical Technologies and Analytics
- Vienna University of Technology
- A-1060 Vienna
- Austria
| | - Matthias Weil
- Institute of Chemical Technologies and Analytics
- Vienna University of Technology
- A-1060 Vienna
- Austria
| | - Kurt Mereiter
- Institute of Chemical Technologies and Analytics
- Vienna University of Technology
- A-1060 Vienna
- Austria
| | - Ernst Pittenauer
- Institute of Chemical Technologies and Analytics
- Vienna University of Technology
- A-1060 Vienna
- Austria
| | - Günter Allmaier
- Institute of Chemical Technologies and Analytics
- Vienna University of Technology
- A-1060 Vienna
- Austria
| | - Luis F. Veiros
- Centro de Química Estrutural
- Instituto Superior Técnico
- Universidade de Lisboa
- 1049-001 Lisboa
- Portugal
| | - Karl Kirchner
- Institute of Applied Synthetic Chemistry
- Vienna University of Technology
- A-1060 Vienna
- Austria
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Murugesan S, Stöger B, Carvalho MD, Ferreira L, Pittenauer E, Allmaier G, Veiros LF, Kirchner K. Synthesis and Reactivity of Four- and Five-Coordinate Low-Spin Cobalt(II) PCP Pincer Complexes and Some Nickel(II) Analogues. Organometallics 2014; 33:6132-6140. [PMID: 27642210 PMCID: PMC5021385 DOI: 10.1021/om5007769] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Indexed: 11/29/2022]
Abstract
Anhydrous CoCl2 or [NiCl2(DME)] reacts with the ligand PCPMe-iPr (1) in the presence of nBuLi to afford the 15e and 16e square planar complexes [Co(PCPMe-iPr)Cl] (2) and [Ni(PCPMe-iPr)Cl] (3), respectively. Complex 2 is a paramagnetic d7 low-spin complex, which is a useful precursor for a series of Co(I), Co(II), and Co(III) PCP complexes. Complex 2 reacts readily with CO and pyridine to afford the five-coordinate square-pyramidal 17e complexes [Co(PCPMe-iPr)(CO)Cl] (4) and [Co(PCPMe-iPr)(py)Cl] (5), respectively, while in the presence of Ag+ and CO the cationic complex [Co(PCPMe-iPr)(CO)2]+ (6) is afforded. The effective magnetic moments μeff of all Co(II) complexes were derived from the temperature dependence of the inverse molar magnetic susceptibility by SQUID measurements and are in the range 1.9 to 2.4 μB. This is consistent with a d7 low-spin configuration with some degree of spin-orbit coupling. Oxidation of 2 with CuCl2 affords the paramagnetic Co(III) PCP complex [Co(PCPMe-iPr)Cl2] (7), while the synthesis of the diamagnetic Co(I) complex [Co(PCPMe-iPr)(CO)2] (8) was achieved by stirring 2 in toluene with KC8 in the presence of CO. Finally, the cationic 16e Ni(II) PCP complex [Ni(PCPMe-iPr)(CO)]+ (10) was obtained by reacting complex 3 with 1 equiv of AgSbF6 in the presence of CO. The reactivity of CO addition to Co(I), Co(II), and Ni(II) PCP square planar complexes of the type [M(PCPMe-iPr)(CO)] n (n = +1, 0) was investigated by DFT calculations, showing that formation of the Co species, 6 and 8, is thermodynamically favorable, while Ni(II) maintains the 16e configuration since CO addition is unfavorable in this case. X-ray structures of most complexes are provided and discussed. A structural feature of interest is that the apical CO ligand in 4 deviates significantly from linearity, with a Co-C-O angle of 170.0(1)°. The DFT-calculated value is 172°, clearly showing that this is not a packing but an electronic effect.
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Affiliation(s)
- Sathiyamoorthy Murugesan
- Institute
of Applied Synthetic Chemistry and Institute of Chemical Technologies
and Analytics, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
| | - Berthold Stöger
- Institute
of Applied Synthetic Chemistry and Institute of Chemical Technologies
and Analytics, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
| | - Maria Deus Carvalho
- Centro de Química e Bioquímica/DQB and Centro de Física
da Matéria
Condensada, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Liliana
P. Ferreira
- Centro de Química e Bioquímica/DQB and Centro de Física
da Matéria
Condensada, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
- Department
of Physics, University of Coimbra, 3004-516 Coimbra, Portugal
| | - Ernst Pittenauer
- Institute
of Applied Synthetic Chemistry and Institute of Chemical Technologies
and Analytics, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
| | - Günter Allmaier
- Institute
of Applied Synthetic Chemistry and Institute of Chemical Technologies
and Analytics, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
| | - Luis F. Veiros
- Centro de
Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais No. 1, 1049-001 Lisboa, Portugal
| | - Karl Kirchner
- Institute
of Applied Synthetic Chemistry and Institute of Chemical Technologies
and Analytics, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
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Four- and five-coordinate high-spin iron(II) complexes bearing bidentate soft/hard SN ligands based on 2-aminopyridine. Polyhedron 2014. [DOI: 10.1016/j.poly.2014.05.052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Holzhacker C, Calhorda MJ, Gil A, Carvalho MD, Ferreira LP, Stöger B, Mereiter K, Weil M, Müller D, Weinberger P, Pittenauer E, Allmaier G, Kirchner K. Six-coordinate high-spin iron(ii) complexes with bidentate PN ligands based on 2-aminopyridine - new Fe(ii) spin crossover systems. Dalton Trans 2014; 43:11152-64. [PMID: 24695811 DOI: 10.1039/c4dt00186a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Several new octahedral iron(ii) complexes of the type [Fe(PN(R)-Ph)2X2] (X = Cl, Br; R = H, Me) containing bidentate PN(R)-Ph (R = H, Me) (1a,b) ligands based on 2-aminopyridine were prepared. (57)Fe Mössbauer spectroscopy and magnetization studies confirmed in all cases their high spin nature at room temperature with magnetic moments very close to 4.9μB reflecting the expected four unpaired d-electrons in all these compounds. While in the case of the PN(H)-Ph ligand an S = 2 to S = 0 spin crossover was observed at low temperatures, complexes with the N-methylated analog PN(Me)-Ph retain an S = 2 spin state also at low temperatures. Thus, [Fe(PN(H)-Ph)2X2] (2a,3a) and [Fe(PN(Me)-Ph)2X2] (2b,3b) adopt different geometries. In the first case a cis-Cl,P,N-arrangement seems to be most likely, as supported by various experimental data derived from (57)Fe Mössbauer spectroscopy, SQUID magnetometry, UV/Vis, Raman, and ESI-MS as well as DFT and TDDFT calculations, while in the case of the PN(Me)-Ph ligand a trans-Cl,P,N-configuration is adopted. The latter is also confirmed by X-ray crystallography. In contrast to [Fe(PN(Me)-Ph)2X2] (2b,3b), [Fe(PN(H)-Ph)2X2] (2a,3a) is labile and undergoes rearrangement reactions. In CH3OH, the diamagnetic dicationic complex [Fe(PN(H)-Ph)3](2+) (5) is formed via the intermediacy of cis-P,N-[Fe(κ(2)-P,N-PN(H)-Ph)2(κ(1)-P-PN(H)-Ph)(X)](+) (4a,b) where one PN ligand is coordinated in a κ(1)-P-fashion. In CH3CN the diamagnetic dicationic complex cis-N,P,N-[Fe(PN(H)-Ph)2(CH3CN)2](2+) (6) is formed as a major isomer where the two halide ligands are replaced by CH3CN.
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Affiliation(s)
- Christian Holzhacker
- Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria.
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