1
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Eberle L, Ballmann J. Synthesis of Collidine from Dinitrogen via a Tungsten Nitride. J Am Chem Soc 2024; 146:7979-7984. [PMID: 38489245 DOI: 10.1021/jacs.4c02226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
The synthesis of pyridines from dinitrogen in homogeneous solution is known to be challenging considering that an N2 cleavage step needs to be combined with two N-C coupling steps. Herein, a tungsten complex bearing a tailor-made 2,2'-(tBu2As)2-substituted tolane ligand scaffold was shown to split N2 to afford the corresponding tungsten nitride, which is not the case for the corresponding (iPr2As)2-substituted derivative. The former nitride was then reacted with 2,4,6-trimethylpyrylium triflate, which led to the formation of a tungsten oxo complex, along with collidine. Over the course of this reaction, the O atom of the pyrylium starting material was replaced with an N atom via a hitherto unprecedented skeletal editing process.
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Affiliation(s)
- Lukas Eberle
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, D-69120 Heidelberg Germany
| | - Joachim Ballmann
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, D-69120 Heidelberg Germany
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2
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Eberle L, Lindenthal S, Ballmann J. To Split or Not to Split: [AsCCAs]-Coordinated Mo, W, and Re Complexes and Their Reactivity toward Molecular Dinitrogen. Inorg Chem 2024; 63:3682-3691. [PMID: 38359784 DOI: 10.1021/acs.inorgchem.3c03244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Molybdenum, tungsten, and rhenium halides bearing a 2,2'-(iPr2As)2-substituted diphenylacetylene ([AsCCAs], 1-As) were prepared and reduced under an atmosphere of dinitrogen in order to activate the latter substrate. In the case of molybdenum, a diiodo (2-As) and a triiodo molybdenum precursor (5) were equally suited for reductive N2 splitting, which led to the isolation of [AsCCAs]Mo≡N(I) (3-As) in each case. For tungsten, [AsCCAs]WCl3 (6) was reduced under N2 to afford {[AsCCAs]WCl2}2(N2) (7), which is best described as a dinuclear π8δ4-configured μ-(η1: η1)-N2-bridged dimer. Attempts to reductively cleave the N2 unit in 7 did not lead to the expected tungsten nitride (8), which had to be prepared independently via the treatment of 7 with sodium azide. To arrive at a π10δ4-configured N2-bridged dimer in a tetragonally distorted ligand environment, [AsCCAs]ReCl3 (9) was reduced in the presence of N2. As expected, a μ-(η1: η1)-N2-bridged dirhenium species, namely, {[AsCCAs]ReCl2}2(N2) (10), was formed, but found to very quickly decompose (presumably via loss of N2), not only under reduced pressure, but also upon irradiation or heating. Hence, an alternative synthetic route to the originally envisioned nitride, [AsCCAs]Re≡N(Cl)2 (11), was developed. While all the aforementioned nitrides (3-As, 8, and 11) were found to be fairly robust, significantly different stabilities were noticed for {[AsCCAs]MCl2}2(N2) (7 for M = W, 10 for M = Re), which is ascribed to the electronically different MN2M cores (π8δ4 for 7 vs π10δ4 for 10) in these μ-(η1: η1)-N2-bridged dimers.
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Affiliation(s)
- Lukas Eberle
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, Heidelberg D-69120, Germany
| | - Sebastian Lindenthal
- Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, Heidelberg D-69120, Germany
| | - Joachim Ballmann
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, Heidelberg D-69120, Germany
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3
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Kimber P, Goddard P, Wright IA, Plasser F. The role of excited-state character, structural relaxation, and symmetry breaking in enabling delayed fluorescence activity in push-pull chromophores. Phys Chem Chem Phys 2021; 23:26135-26150. [PMID: 34792045 DOI: 10.1039/d1cp03792g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Thermally activated delayed fluorescence (TADF) is a current promising route for generating highly efficient light-emitting devices. However, the design process of new chromophores is hampered by the complicated underlying photophysics. In this work, four closely related donor-π-acceptor-π-donor systems are investigated, two of which were synthesised previously, with the aim of elucidating their varying effectiveness for TADF. We outline that the frontier orbitals are insufficient for discriminating between the molecules. Subsequently, a detailed analysis of the excited states at a correlated ab initio level highlights the presence of a number of closely spaced singlet and triplet states of varying character. Results from five density functionals are compared against this reference revealing dramatic changes in, both, excited state energies and wavefunctions following variations in the amount of Hartree-Fock exchange included. Excited-state minima are optimised in solution showing the crucial role of structural variations and symmetry breaking for producing a strongly emissive S1 state. The adiabatic singlet-triplet gaps thus obtained depend strongly on the range separation parameter used in the hybrid density functional calculations. More generally, this work highlights intricate differences present between singlet and triplet excited state wavefunctions and the challenges in describing them accurately.
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Affiliation(s)
- Patrick Kimber
- Department of Chemistry, Loughborough University, Loughborough, LE11 3TU, UK.
| | - Pooja Goddard
- Department of Chemistry, Loughborough University, Loughborough, LE11 3TU, UK.
| | - Iain A Wright
- Department of Chemistry, Loughborough University, Loughborough, LE11 3TU, UK.
| | - Felix Plasser
- Department of Chemistry, Loughborough University, Loughborough, LE11 3TU, UK.
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4
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Yamout LS, Ataya M, Hasanayn F, Holland PL, Miller AJM, Goldman AS. Understanding Terminal versus Bridging End-on N 2 Coordination in Transition Metal Complexes. J Am Chem Soc 2021; 143:9744-9757. [PMID: 34180663 DOI: 10.1021/jacs.1c01146] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Terminal and bridging end-on coordination of N2 to transition metal complexes offer possibilities for distinct pathways in ammonia synthesis and N2 functionalization. Here we elucidate the fundamental factors controlling the two binding modes and determining which is favored for a given metal-ligand system, using both quantitative density functional theory (DFT) and qualitative molecular orbital (MO) analyses. The Gibbs free energy for converting two terminal MN2 complexes into a bridging MNNM complex and a free N2 molecule (2ΔGeq°) is examined through systematic variations of the metal and ligands; values of ΔGeq° range between +9.1 and -24.0 kcal/mol per M-N2 bond. We propose a model that accounts for these broad variations by assigning a fixed π-bond order (BOπ) to the triatomic terminal MNN moiety that is equal to that of the free N2 molecule, and a variable BOπ to the bridging complexes based on the character (bonding or antibonding) and occupancy of the π-MOs in the tetratomic MNNM core. When the conversion from terminal to bridging coordination and free N2 is associated with an increase in the number of π-bonds (ΔBOeqπ > 0), the bridging mode is greatly favored; this condition is satisfied when each metal provides 1, 2, or 3 electrons to the π-MOs of the MNNM core. When each metal in the bridging complex provides 4 electrons to the MNNM π-MOs, ΔBOeqπ = 0; the equilibrium in this case is approximately ergoneutral and the direction can be shifted by dispersion interactions.
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Affiliation(s)
- Lynn S Yamout
- Department of Chemistry, American University of Beirut, Beirut 1107 2020, Lebanon
| | - Mohamad Ataya
- Department of Chemistry, American University of Beirut, Beirut 1107 2020, Lebanon
| | - Faraj Hasanayn
- Department of Chemistry, American University of Beirut, Beirut 1107 2020, Lebanon
| | - Patrick L Holland
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Alexander J M Miller
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Alan S Goldman
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, United States
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5
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Schluschaß B, Borter JH, Rupp S, Demeshko S, Herwig C, Limberg C, Maciulis NA, Schneider J, Würtele C, Krewald V, Schwarzer D, Schneider S. Cyanate Formation via Photolytic Splitting of Dinitrogen. JACS AU 2021; 1:879-894. [PMID: 34240082 PMCID: PMC8243327 DOI: 10.1021/jacsau.1c00117] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Indexed: 05/05/2023]
Abstract
Light-driven N2 cleavage into molecular nitrides is an attractive strategy for synthetic nitrogen fixation. However, suitable platforms are rare. Furthermore, the development of catalytic protocols via this elementary step suffers from poor understanding of N-N photosplitting within dinitrogen complexes, as well as of the thermochemical and kinetic framework for coupled follow-up chemistry. We here present a tungsten pincer platform, which undergoes fully reversible, thermal N2 splitting and reverse nitride coupling, allowing for experimental derivation of thermodynamic and kinetic parameters of the N-N cleavage step. Selective N-N splitting was also obtained photolytically. DFT computations allocate the productive excitations within the {WNNW} core. Transient absorption spectroscopy shows ultrafast repopulation of the electronic ground state. Comparison with ground-state kinetics and resonance Raman data support a pathway for N-N photosplitting via a nonstatistically vibrationally excited ground state that benefits from vibronically coupled structural distortion of the core. Nitride carbonylation and release are demonstrated within a full synthetic cycle for trimethylsilylcyanate formation directly from N2 and CO.
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Affiliation(s)
- Bastian Schluschaß
- University
of Göttingen, Institute for Inorganic
Chemistry, Tammannstraße
4, 37077 Göttingen, Germany
| | - Jan-Hendrik Borter
- Department
of Dynamics at Surfaces, Max Planck Institute
for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Severine Rupp
- Theoretische
Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 4, 64287 Darmstadt, Germany
| | - Serhiy Demeshko
- University
of Göttingen, Institute for Inorganic
Chemistry, Tammannstraße
4, 37077 Göttingen, Germany
| | - Christian Herwig
- Institut
für Chemie, Humboldt Universität
zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Christian Limberg
- Institut
für Chemie, Humboldt Universität
zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Nicholas A. Maciulis
- Department
of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405-7102, United States
| | - Jessica Schneider
- University
of Göttingen, Institute for Inorganic
Chemistry, Tammannstraße
4, 37077 Göttingen, Germany
| | - Christian Würtele
- University
of Göttingen, Institute for Inorganic
Chemistry, Tammannstraße
4, 37077 Göttingen, Germany
| | - Vera Krewald
- Theoretische
Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 4, 64287 Darmstadt, Germany
| | - Dirk Schwarzer
- Department
of Dynamics at Surfaces, Max Planck Institute
for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Sven Schneider
- University
of Göttingen, Institute for Inorganic
Chemistry, Tammannstraße
4, 37077 Göttingen, Germany
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6
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Forrest SJK, Schluschaß B, Yuzik-Klimova EY, Schneider S. Nitrogen Fixation via Splitting into Nitrido Complexes. Chem Rev 2021; 121:6522-6587. [DOI: 10.1021/acs.chemrev.0c00958] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sebastian J. K. Forrest
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Bastian Schluschaß
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | | | - Sven Schneider
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
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