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Crumpton AE, Heilmann A, Aldridge S. Modulating Hydrogen Shuttling in Ammonia by Neutral and Cationic Boron-Containing Frustrated Lewis Pairs (FLPs). Angew Chem Int Ed Engl 2024:e202406440. [PMID: 38818696 DOI: 10.1002/anie.202406440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 05/27/2024] [Accepted: 05/28/2024] [Indexed: 06/01/2024]
Abstract
Xanthene-backbone FLPs featuring secondary borane functions -B(ArX)H (where ArX=C6F5 (ArF) or C6Cl5 (ArCl)) have been targeted through reactions of the dihydroboranes Me2S ⋅ BArXH2 with [4,5-xanth(PR2)Li]2 (R=Ph, iPr), and investigated in the synthesis of related cationic systems via hydride abstraction. The reactivity of these systems (both cationic and charge neutral) with ammonia have been probed, with a view to probing the potential for proton shuttling via N-H bond 'activation.' We find that in the case of four-coordinate boron systems (cationic or change neutral), the N-H linkage remains intact, supported by a NH⋅⋅⋅P hydrogen bond which is worth up to 17 kcal mol-1 thermodynamically, and enabled by planarization of the flexible xanthene scaffold. For cationic three coordinate systems, N-to-P proton transfer is viable, driven by the ability of the boron centre to stabilise the [NH2]- conjugate base through N-to-B π bonding. This proton transfer can be shown to be reversible in the presence of excess ammonia, depending on the nature of the B-bound ArX group. It is viable in the case of C6F5 substituents, but is prevented by the more sterically encumbering and secondary donor-stabilising capabilities of the C6Cl5 substituent.
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Affiliation(s)
- Agamemnon E Crumpton
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Andreas Heilmann
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Simon Aldridge
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
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Wang Y, Xie Y, Threlkeld HL, Wei P, Schaefer HF, Robinson GH. Labile Imidazolium Cyclopentadienides. Organometallics 2019. [DOI: 10.1021/acs.organomet.9b00589] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yuzhong Wang
- Department of Chemistry and the Center for Computational Chemistry, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Yaoming Xie
- Department of Chemistry and the Center for Computational Chemistry, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Holli L. Threlkeld
- Department of Chemistry and the Center for Computational Chemistry, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Pingrong Wei
- Department of Chemistry and the Center for Computational Chemistry, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Henry F. Schaefer
- Department of Chemistry and the Center for Computational Chemistry, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Gregory H. Robinson
- Department of Chemistry and the Center for Computational Chemistry, The University of Georgia, Athens, Georgia 30602-2556, United States
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Richter J, Liebing P, Edelmann FT. Early transition metal and lanthanide metallocenes bearing dihydroazulenide ligands. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2017.06.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bachmann S, Gernert B, Stalke D. Solution structures of alkali metal cyclopentadienides in THF estimated by ECC-DOSY NMR-spectroscopy (incl. software). Chem Commun (Camb) 2018; 52:12861-12864. [PMID: 27731871 DOI: 10.1039/c6cc07273a] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In this paper we present the aggregational motifs of the widely used alkali-metal cyclopentadienides (CpLi, CpNa, CpK, CpRb, CpCs) in THF-d8 solution estimated by ECC-DOSY NMR spectroscopy. They form monomeric contact ion pairs (CIPs) in THF-d8 solution, whereas in NH3 solvent-separated ion pairs (SSIPs) are observed. The applicability of ECC-DOSY is further advanced by introducing ECC-MW estimation software.
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Affiliation(s)
- Sebastian Bachmann
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstraße 4, D-37077, Göttingen, Germany.
| | - Björn Gernert
- Institut für Betriebssysteme und Rechnerverbund, TU Braunschweig, Mühlenpfordstraße 23, Braunschweig, D-38106, Germany
| | - Dietmar Stalke
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstraße 4, D-37077, Göttingen, Germany.
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Neufeld R, Michel R, Herbst-Irmer R, Schöne R, Stalke D. Introducing a Hydrogen-Bond Donor into a Weakly Nucleophilic Brønsted Base: Alkali Metal Hexamethyldisilazides (MHMDS, M=Li, Na, K, Rb and Cs) with Ammonia. Chemistry 2016; 22:12340-6. [PMID: 27457218 DOI: 10.1002/chem.201600833] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 05/25/2016] [Indexed: 11/08/2022]
Abstract
Alkali metal 1,1,1,3,3,3-hexamethyldisilazide (MHMDSs) are one of the most utilised weakly nucleophilic Brønsted bases in synthetic chemistry and especially in natural product synthesis. Like lithium organics, they aggregate depending on the employed donor solvents. Thus, they show different reactivity and selectivity as a function of their aggregation and solvation state. To date, monomeric LiHMDS with monodentate donor bases was only characterised in solution. Since the first preparation of LiHMDS in 1959 by Wannagat and Niederprüm, all efforts to crystallise monomeric LiHMDS in the absence of chelating ligands failed. Herein, we present ammonia adducts of LiHMDS, NaHMDS, KHMDS, RbHMDS and CsHMDS with unprecedented aggregation motifs: 1) The hitherto missing monomeric key compound in the LiHMDS aggregation architectures. Monomeric crystal structures of trisolvated LiHMDS (1) and NaHMDS (2), showing unique intermolecular hydrogen bonds, 2) the unprecedented tetrasolvated KHMDS (3) and RbHMDS (4) dimers and 3) the disolvated CsHMDS (5) dimer with very close intermolecular Si-CH3 ⋅⋅⋅Cs s-block "agostic" interactions have been prepared and characterised by single-crystal X-ray structure analysis.
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Affiliation(s)
- Roman Neufeld
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, 37077, Göttingen, Germany
| | - Reent Michel
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, 37077, Göttingen, Germany
| | - Regine Herbst-Irmer
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, 37077, Göttingen, Germany
| | - Ralf Schöne
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, 37077, Göttingen, Germany
| | - Dietmar Stalke
- Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, 37077, Göttingen, Germany.
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Kotyk CM, MacDonald MR, Ziller JW, Evans WJ. Reactivity of the Ln2+ Complexes [K(2.2.2-cryptand)][(C5H4SiMe3)3Ln]: Reduction of Naphthalene and Biphenyl. Organometallics 2015. [DOI: 10.1021/om501063h] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Christopher M. Kotyk
- Department
of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Matthew R. MacDonald
- Department
of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Joseph W. Ziller
- Department
of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - William J. Evans
- Department
of Chemistry, University of California, Irvine, California 92697-2025, United States
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Reich HJ. Role of Organolithium Aggregates and Mixed Aggregates in Organolithium Mechanisms. Chem Rev 2013; 113:7130-78. [DOI: 10.1021/cr400187u] [Citation(s) in RCA: 248] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Hans J. Reich
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, United States
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Hey J, Andrada DM, Michel R, Mata RA, Stalke D. Ein kleiner Klavierstuhl-Komplex, geformt durch starke intermolekulare Wechselwirkungen. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201304498] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Hey J, Andrada DM, Michel R, Mata RA, Stalke D. Strong Intermolecular Interactions Shaping a Small Piano-Stool Complex. Angew Chem Int Ed Engl 2013; 52:10365-9. [DOI: 10.1002/anie.201304498] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Indexed: 11/10/2022]
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Michel R, Nack T, Neufeld R, Dieterich JM, Mata RA, Stalke D. The Layered Structure of [Na(NH3)4][Indenide] Containing a Square-Planar Na(NH3)4+Cation. Angew Chem Int Ed Engl 2012; 52:734-8. [DOI: 10.1002/anie.201207082] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Indexed: 11/10/2022]
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Michel R, Nack T, Neufeld R, Dieterich JM, Mata RA, Stalke D. Schichtstruktur von [Na(NH3)4][Indenid] mit quadratisch-planarem Na(NH3)4+-Kation. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201207082] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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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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Tay BY, Wang C, Stubbs LP, Jacob C, van Meurs M. Deuterated dimethyl sulfoxide as a good NMR solvent for the characterization of alkali metal cyclopentadienides, amides, alkoxides and phenoxides. J Organomet Chem 2011. [DOI: 10.1016/j.jorganchem.2011.07.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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