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Schwarz C, Scharf LT, Scherpf T, Weismann J, Gessner VH. Isolation of the Metalated Ylides [Ph 3 P-C-CN]M (M=Li, Na, K): Influence of the Metal Ion on the Structure and Bonding Situation. Chemistry 2019; 25:2793-2802. [PMID: 30556625 PMCID: PMC6519153 DOI: 10.1002/chem.201805421] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Indexed: 11/24/2022]
Abstract
The isolation and structural characterization of the cyanido-substituted metalated ylides [Ph3 P-C-CN]M (1-M; M=Li, Na, K) are reported with lithium, sodium, and potassium as metal cations. In the solid-state, most different aggregates could be determined depending on the metal and additional Lewis bases. The crown-ether complexes of sodium (1-Na) and potassium (1-K) exhibited different structures, with sodium preferring coordination to the nitrogen end, whereas potassium binds in an unusual η2 -coordination mode to the two central carbon atoms. The formation of the yldiide was accompanied by structural changes leading to shorter C-C and longer C-N bonds. This could be attributed to the delocalization of the free electron pairs at the carbon atom into the antibonding orbitals of the CN moiety, which was confirmed by IR spectroscopy and computational studies. Detailed density functional theory calculations show that the changes in the structure and the bonding situation were most pronounced in the lithium compounds due to the higher covalency.
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Weber P, Scherpf T, Rodstein I, Lichte D, Scharf LT, Gooßen LJ, Gessner VH. Ein hochaktives, Ylid‐funktionalisiertes Phosphan für die palladiumkatalysierte Aminierung von Arylchloriden. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201810696] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Weber P, Scherpf T, Rodstein I, Lichte D, Scharf LT, Gooßen LJ, Gessner VH. A Highly Active Ylide-Functionalized Phosphine for Palladium-Catalyzed Aminations of Aryl Chlorides. Angew Chem Int Ed Engl 2019; 58:3203-3207. [PMID: 30451339 DOI: 10.1002/anie.201810696] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Indexed: 11/10/2022]
Abstract
Ylide-functionalized phosphine ligands (YPhos) were rationally designed to fit the requirements of Buchwald-Hartwig aminations at room temperature. This ligand class combines a strong electron-donating ability comparable to NHC ligands with high steric demand similar to biaryl phosphines. The active Pd species are stabilized by agostic C-H⋅⋅⋅Pd rather than by Pd-arene interactions. The practical advantage of YPhos ligands arises from their easy and scalable synthesis from widely available, inexpensive starting materials. Benchmark studies showed that YPhos-Pd complexes are superior to the best-known phosphine ligands in room-temperature aminations of aryl chlorides. The utility of the catalysts was demonstrated by the synthesis of various arylamines in high yields within short reaction times.
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Schwarz C, Handelmann J, Baier DM, Ouissa A, Gessner VH. Mono- and diylide-substituted phosphines (YPhos): impact of the ligand properties on the catalytic activity in gold(i)-catalysed hydroaminations. Catal Sci Technol 2019. [DOI: 10.1039/c9cy01861a] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The monoylide-phosphines show a linear correlation between their donor strength and their activity in gold-catalysed hydroaminations, while steric congestions leads to lower activities of the diylide congeners despite their higher donor properties.
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Scherpf T, Schwarz C, Scharf LT, Zur JA, Helbig A, Gessner VH. Cover Picture: Ylide-Functionalized Phosphines: Strong Donor Ligands for Homogeneous Catalysis (Angew. Chem. Int. Ed. 39/2018). Angew Chem Int Ed Engl 2018. [DOI: 10.1002/anie.201808282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Scherpf T, Schwarz C, Scharf LT, Zur JA, Helbig A, Gessner VH. Titelbild: Ylide-Functionalized Phosphines: Strong Donor Ligands for Homogeneous Catalysis (Angew. Chem. 39/2018). Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201808282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Scherpf T, Schwarz C, Scharf LT, Zur JA, Helbig A, Gessner VH. Ylide-Functionalized Phosphines: Strong Donor Ligands for Homogeneous Catalysis. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201805372] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Scherpf T, Schwarz C, Scharf LT, Zur JA, Helbig A, Gessner VH. Ylide-Functionalized Phosphines: Strong Donor Ligands for Homogeneous Catalysis. Angew Chem Int Ed Engl 2018; 57:12859-12864. [PMID: 29862622 PMCID: PMC6174943 DOI: 10.1002/anie.201805372] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Indexed: 12/25/2022]
Abstract
Phosphines are important ligands in homogenous catalysis and have been crucial for many advances, such as in cross‐coupling, hydrofunctionalization, or hydrogenation reactions. Herein we report the synthesis and application of a novel class of phosphines bearing ylide substituents. These phosphines are easily accessible via different synthetic routes from commercially available starting materials. Owing to the extra donation from the ylide group to the phosphorus center the ligands are unusually electron‐rich and can thus function as strong electron donors. The donor capacity surpasses that of commonly used phosphines and carbenes and can easily be tuned by changing the substitution pattern at the ylidic carbon atom. The huge potential of ylide‐functionalized phosphines in catalysis is demonstrated by their use in gold catalysis. Excellent performance at low catalyst loadings under mild reaction conditions is thus seen in different types of transformations.
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Scharf LT, Weismann J, Feichtner KS, Lindl F, Gessner VH. Versatile Modes of Cooperative B−H Bond Activation Reactions in Ruthenium-Carbene Complexes: Addition, Ring-Opening and Insertion. Chemistry 2018; 24:3439-3443. [DOI: 10.1002/chem.201800248] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Indexed: 12/30/2022]
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Feichtner KS, Gessner VH. Cooperative bond activation reactions with carbene complexes. Chem Commun (Camb) 2018; 54:6540-6553. [DOI: 10.1039/c8cc02198h] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This review highlights the recent advances in the application of carbene complexes in bond activation reactions via metal–ligand cooperation.
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Scharf LT, Gessner VH. Metalated Ylides: A New Class of Strong Donor Ligands with Unique Electronic Properties. Inorg Chem 2017; 56:8599-8607. [PMID: 28240888 PMCID: PMC5549244 DOI: 10.1021/acs.inorgchem.7b00099] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Indexed: 11/29/2022]
Abstract
The development and design of new ligand systems with special donor properties has been essential for crucial advances made in main-group-element and transition-metal chemistry over the years. This Forum Article focuses on metalated ylides as novel ligand systems. These anionic congeners of bisylides possess likewise two lone pairs of electrons at the central carbon atom and can thus function as X,L-type ligands with strong donor abilities. This article highlights recent efforts in the isolation and application of metalated ylides with a focus on work from this laboratory. We summarize structural and electronic properties and their use in organic synthesis as well as main-group-element and transition-metal chemistry.
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Molitor S, Gessner VH. Alkali Metal Chlorine and Bromine Carbenoids: Their Thermal Stability and Structural Properties. Chemistry 2017; 23:12372-12379. [PMID: 28597985 DOI: 10.1002/chem.201701911] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Indexed: 01/14/2023]
Abstract
The synthesis and structures of a series of M/X carbenoids of the type [Ph2 P(S)]2 CMX with M=Li, Na, and K and X=Cl and Br are reported, amongst the first isolated Na/Br and K/Br carbenoids. NMR spectroscopic as well as crystallographic studies showed distinct differences between the lithium carbenoids and their heavier congeners. In the solid state, all carbenoids showed no direct metal-carbon interaction, but an interaction between the metal and the halogen atom. This contact is only very weak in the case of the Li/Br carbenoid, but much more pronounced in the corresponding potassium and sodium compounds. Nevertheless, these interactions did not significantly influence the stability of the carbenoids by weakening the C-X bond and facilitating the MX elimination. As such all compounds were found to be stable up to approximately 60 °C in solution. Hence, M-X interactions-albeit being an essential feature for the structure formation of carbenoids-are not the only criterion determining the stability of such compounds. In the present systems, the stabilization by the thiophosphinoyl moieties is more important than the metal/halogen combination.
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Feichtner KS, Scherpf T, Gessner VH. Cooperative Bond Activation Reactions with Ruthenium Carbene Complex PhSO2(Ph2PNSiMe3)C═Ru(p-cymene): Ru═C and N–Si Bond Reactivity. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00254] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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64
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Scharf LT, Andrada DM, Frenking G, Gessner VH. The Bonding Situation in Metalated Ylides. Chemistry 2017; 23:4422-4434. [PMID: 28121371 PMCID: PMC5396261 DOI: 10.1002/chem.201605997] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Indexed: 11/07/2022]
Abstract
Quantum chemical calculations have been carried out to study the electronic structure of metalated ylides particularly in comparison to their neutral analogues, the bisylides. A series of compounds of the general composition Ph3 P-C-L with L being either a neutral or an anionic ligand were analyzed and the impact of the nature of the substituent L and the total charge on the electronics and bonding situation was studied. The charge at the carbon atom as well as the dissociation energies, bond lengths, and Wiberg bond indices strongly depend on the nature of L. Here, not only the charge of the ligand but also the position of the charge within the ligand backbone plays an important role. Independent of the substitution pattern, the NBO analysis reveals the preference of unsymmetrical bonding situations (P=C-L or P-C=L) for almost all compounds. However, Lewis structures with two lone-pair orbitals at the central carbon atom are equally valid for the description of the bonding situation. This is confirmed by the pronounced lone-pair character of the frontier orbitals. Energy decomposition analysis mostly reveals the preference of several bonding situations, mostly with dative and ylidic electron-sharing bonds (e.g., P→C- -L). In general, the anionic systems show a higher preference of the ylidic bonding situations compared to the neutral analogues. However, in most of the cases different resonance structures have to be considered for the description of the "real" bonding situation.
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Scherpf T, Feichtner K, Gessner VH. Using Ylide Functionalization to Stabilize Boron Cations. Angew Chem Int Ed Engl 2017; 56:3275-3279. [PMID: 28185370 PMCID: PMC5363341 DOI: 10.1002/anie.201611677] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/26/2017] [Indexed: 11/17/2022]
Abstract
The metalated ylide YNa [Y=(Ph3 PCSO2 Tol)- ] was employed as X,L-donor ligand for the preparation of a series of boron cations. Treatment of the bis-ylide functionalized borane Y2 BH with different trityl salts or B(C6 F5 )3 for hydride abstraction readily results in the formation of the bis-ylide functionalized boron cation [Y-B-Y]+ (2). The high donor capacity of the ylide ligands allowed the isolation of the cationic species and its characterization in solution as well as in solid state. DFT calculations demonstrate that the cation is efficiently stabilized through electrostatic effects as well as π-donation from the ylide ligands, which results in its high stability. Despite the high stability of 2 [Y-B-Y]+ serves as viable source for the preparation of further borenium cations of type Y2 B+ ←LB by addition of Lewis bases such as amines and amides. Primary and secondary amines react to tris(amino)boranes via N-H activation across the B-C bond.
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Molitor S, Gessner VH. Synthesis, structure and thermal stability of a crown ether complexed K/Cl carbenoid. Inorganica Chim Acta 2017. [DOI: 10.1016/j.ica.2016.11.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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67
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Molitor S, Feichtner KS, Gessner VH. Back Cover: Taming Metal/Fluorine Carbenoids (Chem. Eur. J. 11/2017). Chemistry 2017. [DOI: 10.1002/chem.201605713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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68
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Scherpf T, Feichtner KS, Gessner VH. Using Ylide Functionalization to Stabilize Boron Cations. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611677] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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69
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Molitor S, Feichtner KS, Gessner VH. Taming Metal/Fluorine Carbenoids. Chemistry 2017; 23:2527-2531. [PMID: 27906492 DOI: 10.1002/chem.201605592] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Indexed: 12/18/2022]
Abstract
Although Li/Cl carbenoids are versatile reagents in organic synthesis, the controlled handling of the extremely reactive and labile M/F carbenoids remains a challenge. We now show that even these compounds can be stabilized and isolated in solid state, as well as in solution. Particularly the sodium and potassium compounds exhibit a remarkable stability, thus allowing the first isolation of a room-temperature-stable fluorine carbenoid. Spectroscopic, as well as DFT studies confirmed the pronounced carbenoid character, showing M-F-C interactions with elongated C-F bonds. The different stabilities of the carbenoids was found to originate from the different strength of the M-F interaction. Hence, the lithium compounds are considerably more reactive than their heavier congeners. Reactivity studies showed that the nature of the metal also influences the reactivity, resulting in different selectivity in the addition to thioketones.
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Gessner VH. Stability and reactivity control of carbenoids: recent advances and perspectives. Chem Commun (Camb) 2016; 52:12011-12023. [PMID: 27498609 DOI: 10.1039/c6cc05524a] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Metal carbenoids such as lithium or Simmons-Smith-type reagents are widely used in organic synthesis, particularly in cyclopropanation and homologation reactions. These reagents are often highly reactive and thermally labile, thus limiting their isolation and hampering the development of new synthetic applications. Recent years however, have shown that by means of systematic stabilization a control of reactivity and the development of new applications is possible. This feature article documents recent developments in the control of carbenoid reactivity and stability and highlights structural and electronic properties as well as applications in main group element and transition metal chemistry.
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Weismann J, Scharf LT, Gessner VH. Cooperative P–H Bond Activation with Ruthenium and Iridium Carbene Complexes. Organometallics 2016. [DOI: 10.1021/acs.organomet.6b00408] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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72
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Molitor S, Gessner VH. Innenrücktitelbild: Alkali Metal Carbenoids: A Case of Higher Stability of the Heavier Congeners (Angew. Chem. 27/2016). Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201603827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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73
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Molitor S, Gessner VH. Inside Back Cover: Alkali Metal Carbenoids: A Case of Higher Stability of the Heavier Congeners (Angew. Chem. Int. Ed. 27/2016). Angew Chem Int Ed Engl 2016. [DOI: 10.1002/anie.201603827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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74
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Molitor S, Gessner VH. Alkali Metal Carbenoids: A Case of Higher Stability of the Heavier Congeners. Angew Chem Int Ed Engl 2016; 55:7712-6. [PMID: 27100278 DOI: 10.1002/anie.201601356] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Indexed: 11/12/2022]
Abstract
As a result of the increased polarity of the metal-carbon bond when going down the group of the periodic table, the heavier alkali metal organyl compounds are generally more reactive and less stable than their lithium congeners. We now report a reverse trend for alkali metal carbenoids. Simple substitution of lithium by the heavier metals (Na, K) results in a significant stabilization of these usually highly reactive compounds. This allows their isolation and handling at room temperature and the first structure elucidation of sodium and potassium carbenoids. The control of stability was used to control reactivity and selectivity. Hence, the Na and K carbenoids act as selective carbene-transfer reagents, whereas the more labile lithium systems give rise to product mixtures. Additional fine tuning of the M-C interaction by means of crown ether addition further allows for control of the stability and reactivity.
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Molitor S, Gessner VH. Alkali Metal Carbenoids: A Case of Higher Stability of the Heavier Congeners. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201601356] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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76
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Weismann J, Waterman R, Gessner VH. Metal-Ligand Cooperativity in a Methandiide-Derived Iridium Carbene Complex. Chemistry 2016; 22:3846-55. [DOI: 10.1002/chem.201503936] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Indexed: 11/09/2022]
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77
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Molitor S, Mahler C, Gessner VH. Synthesis and solid-state structures of gold(i) complexes of diphosphines. NEW J CHEM 2016. [DOI: 10.1039/c6nj00786d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of diphosphine bis(gold) complexes were synthesised and the importance of aurophilic interactions for their structure formation was studied.
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Molitor S, Schwarz C, Gessner VH. Mono- and Bis-Cyclometalated Palladium Complexes: Synthesis, Characterization, and Catalytic Activity. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00903] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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79
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Feichtner KS, Englert S, Gessner VH. Preparation and Isolation of a Chiral Methandiide and Its Application as Cooperative Ligand in Bond Activation. Chemistry 2015; 22:506-10. [DOI: 10.1002/chem.201504724] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Indexed: 01/12/2023]
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80
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Weismann J, Gessner VH. Catalytic Transfer Hydrogenation with a Methandiide‐Based Carbene Complex: An Experimental and Computational Study. Chemistry 2015; 21:16103-12. [DOI: 10.1002/chem.201502116] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Indexed: 11/10/2022]
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81
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Scherpf T, Wirth R, Molitor S, Feichtner KS, Gessner VH. Das Bindeglied zwischen Bisyliden und Methandiiden: Isolierung, Reaktivität und elektronische Struktur eines Yldiids. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201501818] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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82
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Scherpf T, Wirth R, Molitor S, Feichtner KS, Gessner VH. Bridging the Gap between Bisylides and Methandiides: Isolation, Reactivity, and Electronic Structure of an Yldiide. Angew Chem Int Ed Engl 2015; 54:8542-6. [DOI: 10.1002/anie.201501818] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 04/09/2015] [Indexed: 11/11/2022]
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83
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Gessner VH, Becker J, Feichtner K. Carbene Complexes Based on Dilithium Methandiides. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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84
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Gessner VH, Becker J, Feichtner K. Carbene Complexes Based on Dilithium Methandiides (Eur. J. Inorg. Chem. 11/2015). Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201590041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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85
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Gessner VH, Becker J, Feichtner KS. Carbene Complexes Based on Dilithium Methandiides. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500051] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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86
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Weismann J, Gessner VH. Si–H activation by means of metal ligand cooperation in a methandiide derived carbene complex. Chem Commun (Camb) 2015; 51:14909-12. [DOI: 10.1039/c5cc05201g] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Si–H bond activation of a series of silanes by means of metal ligand cooperation is reported.
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Molitor S, Becker J, Gessner VH. Selective dehydrocoupling of phosphines by lithium chloride carbenoids. J Am Chem Soc 2014; 136:15517-20. [PMID: 25322474 DOI: 10.1021/ja509381w] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The development of a simple, transition-metal-free approach for the formation of phosphorus-phosphorus bonds through dehydrocoupling of phosphines is presented. The reaction is mediated by electronically stabilized lithium chloride carbenoids and affords a variety of different diphosphines under mild reaction conditions. The developed protocol is simple and highly efficient and allows the isolation of novel functionalized diphosphines in high yields.
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Becker J, Modl T, Gessner VH. Methandiide as a Non-Innocent Ligand in Carbene Complexes: From the Electronic Structure to Bond Activation Reactions and Cooperative Catalysis. Chemistry 2014; 20:11295-9. [DOI: 10.1002/chem.201404131] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Indexed: 11/06/2022]
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89
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Molitor S, Feichtner KS, Kupper C, Gessner VH. Substitution effects on the formation of T-shaped palladium carbene and thioketone complexes from Li/Cl carbenoids. Chemistry 2014; 20:10752-62. [PMID: 24664573 DOI: 10.1002/chem.201304927] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Indexed: 11/05/2022]
Abstract
The preparation of palladium thioketone and T-shaped carbene complexes by treatment of thiophosphoryl substituted Li/Cl carbenoids with a Pd(0) precursor is reported. Depending on the steric demand, the anion-stabilizing ability of the silyl moiety (by negative hyperconjugation effects) and the remaining negative charge at the carbenic carbon atom, isolation of a three-coordinate, T-shaped palladium carbene complex is possible. In contrast, insufficient charge stabilization results in the transfer of the sulfur of the thiophosphoryl moiety and thus in the formation of a thioketone complex. While the thioketones are stable compounds the carbene complexes are revealed to be highly reactive and decompose under elimination of Pd metal. Computational studies revealed that both complexes are formed by a substitution mechanism. While the ketone turned out to be the thermodynamically favored product, the carbene is kinetically favored and thus preferentially formed at low reaction temperatures.
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90
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Gessner VH. Diphen-yl[(phenyl-sulfan-yl)meth-yl]-λ(5)-phosphane-thione. Acta Crystallogr Sect E Struct Rep Online 2014; 70:o374. [PMID: 24765055 PMCID: PMC3998441 DOI: 10.1107/s1600536814004292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 02/25/2014] [Indexed: 12/04/2022]
Abstract
The title compound, C19H17PS2, results from the direct deprotonation of diphenylmethylphosphine sulfide and subsequent reaction with diphenyl disulfide. The C—P and C—S bond lengths of 1.8242 (18) and 1.8009 (18) Å, respectively, of the central P—C—S linkage are comparable to those found in the sulfonyl analogue, but are considerably longer than those reported for the dimetallated sulfonyl compound. The dihedral angle between the benzene rings of the diphenylmethyl moiety is 69.46 (7)°. No distinct intermolecular interactions are present in the crystal structure.
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91
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Becker J, Gessner VH. Synthesis and Electronic Structure of Carbene Complexes Based on a Sulfonyl-Substituted Dilithio Methandiide. Organometallics 2014. [DOI: 10.1021/om5001277] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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92
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Becker J, Gessner VH. On the structure and ambiphilicity of a sulfonyl substituted α-chloro lithium base. Dalton Trans 2014; 43:4320-5. [DOI: 10.1039/c3dt52800f] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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93
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Feichtner KS, Gessner VH. Synthesis and stability of Li/Cl carbenoids based on bis(iminophosphoryl)methanes. Dalton Trans 2014; 43:14399-408. [DOI: 10.1039/c4dt01466a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bis(iminophosphoryl) substituted Li/Cl carbenoids – accessable via different preparation methods – show high thermal stabilities, which however depend on the N-substituent.
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94
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Kupper C, Molitor S, Gessner VH. Structure, Bonding, and Reactivity of Room-Temperature-Stable Lithium Chloride Carbenoids. Organometallics 2013. [DOI: 10.1021/om4010862] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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95
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Gessner VH, Meier F, Uhrich D, Kaupp M. Synthesis and bonding in carbene complexes of an unsymmetrical dilithio methandiide: a combined experimental and theoretical study. Chemistry 2013; 19:16729-39. [PMID: 24150833 DOI: 10.1002/chem.201303115] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Indexed: 11/10/2022]
Abstract
Herein, we report the preparation of a new unsymmetrical, bis(thiophosphinoyl)-substituted dilithio methandiide and its application for the synthesis of zirconium- and palladium-carbene complexes. These complexes were found to exhibit remarkably shielded (13)C NMR shifts, which are much more highfield-shifted than those of "normal" carbene complexes. DFT calculations were performed to determine the origin of these observations and to distinguish the electronic structure of these and related carbene complexes compared with the classical Fischer and Schrock-type complexes. Various methods show that these systems are best described as highly polarized Schrock-type complexes, in which the metal-carbon bond possesses more electrostatic contributions than in the prototype Schrock systems, or even as "masked" methandiides. As such, geminal dianions represent a kind of "extreme" Schrock-type ligands favoring the ionic resonance structure M(+)-CR2(-) as often used in textbooks to explain the nucleophilic nature of Schrock complexes.
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96
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Molitor S, Gessner VH. Reactivity of Stabilized Li/Cl Carbenoids towards Lewis Base Adducts of BH3: BH Bond Activation versus Carbene Dimerization. Chemistry 2013; 19:11858-62. [DOI: 10.1002/chem.201302612] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Revised: 07/05/2013] [Indexed: 11/08/2022]
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97
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Götz K, Gessner VH, Unkelbach C, Kaupp M, Strohmann C. Understanding Structure Formation in Organolithium Compounds: An Experimental and Quantum-Chemical Approach. Z Anorg Allg Chem 2013. [DOI: 10.1002/zaac.201200495] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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98
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Braunschweig H, Dewhurst RD, Gessner VH. Transition metal borylene complexes. Chem Soc Rev 2013; 42:3197-208. [DOI: 10.1039/c3cs35510a] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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99
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Eckert PK, Vieira IDS, Gessner VH, Börner J, Strohmann C, Herres-Pawlis S. Simple is best: Diamine zinc complexes as unexpected catalysts in lactide polymerisation. Polyhedron 2013. [DOI: 10.1016/j.poly.2012.09.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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100
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Hartung A, Seufert F, Berges C, Gessner VH, Holzgrabe U. One-pot Ugi/Aza-Michael synthesis of highly substituted 2,5-diketopiperazines with anti-proliferative properties. Molecules 2012; 17:14685-99. [PMID: 23519247 PMCID: PMC6268348 DOI: 10.3390/molecules171214685] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 12/01/2012] [Accepted: 12/06/2012] [Indexed: 11/17/2022] Open
Abstract
The well-known Ugi reaction of aldehydes with amines, carboxylic acids and isocyanides leads to the formation of acyclic α-acylaminocarboxamides. Replacement of the carboxylic acid derivatives with β-acyl substituted acrylic acids gives access to highly substituted 2,5-diketopiperazines in one single reaction-step without additives or complex reaction procedures. The obtained diketopiperazines show anti-proliferative effects on activated T cells and represent therefore potential candidates for targeting unwanted T cell-mediated immune responses.
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