New developments in synthetic nitrogen fixation with molybdenum and tungsten phosphine complexes

Dreher, Ameli; Stephan, Gerald; Tuczek, Felix

doi:10.1016/s0898-8838(09)00206-2

Cited by 21 publications

(7 citation statements)

References 72 publications

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“…Here, the RIJCOSX approximation has been used in order to accelerate the calculation. The B3LYP functional has previously been found to reliably reproduce the electronic structures, spectroscopic properties, and reactivities of a large number of Mo–N x H y intermediates, both of the Schrock and Chatt cycles. − Self-consistent-field (SCF) convergence was accelerated using the KDIIS and SOSCF methods. , The spin states of the complexes correspond to those of previous calculations ,, and are specified in Table S1 in the Supporting Information (SI).…”

Section: Computational Detailsmentioning

confidence: 99%

Free Reaction Enthalpy Profile of the Schrock Cycle Derived from Density Functional Theory Calculations on the Full [Mo^HIPTN₃N] Catalyst

et al. 2015

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A series of density functional theory (DFT) calculations on the full [Mo(HIPT)N3N] catalyst are performed to obtain an energy profile of the Schrock cycle. This is a continuation of our earlier investigation of this cycle in which the bulky hexaisopropyterphenyl (HIPT) substituents of the ligand were replaced by hydrogen atoms (Angew. Chem., Int. Ed. 2005, 44, 5639). In an effort to provide a treatment that is as converged as possible from a quantum-chemical point of view, the present study now fully takes the HIPT moieties into account. Moreover, structures and energies are calculated with a near-saturated basis set, leading to models with 280 atoms and 4850 basis functions. Solvent and scalar relativistic effects have been treated using the conductor-like screening model and zeroth-order regular approximation, respectively. Free reaction enthalpies are evaluated using the PBE and B3LYP functionals. A comparison to the available experimental data reveals much better agreement with the experiment than preceding DFT treatments of the Schrock cycle. In particular, free reaction enthalpies of reduction steps and NH3/N2 exchange are now excellently reproduced.

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Section: Computational Detailsmentioning

confidence: 99%

Free Reaction Enthalpy Profile of the Schrock Cycle Derived from Density Functional Theory Calculations on the Full [Mo^HIPTN₃N] Catalyst

et al. 2015

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“…At present, we have not yet obtained detailed information on the reaction pathway; however, we consider that the catalytic reaction system described in the present manuscript did not proceed via path A but the classical Chatt cycle (path B), which involved the formation of diazenide, hydrazide, hydrazidium, nitride, imide, amide, and ammine complexes as key reactive intermediates, leading to ammonia formation (Scheme d).…”

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confidence: 91%

Molybdenum-Catalyzed Ammonia Formation Using Simple Monodentate and Bidentate Phosphines as Auxiliary Ligands

et al. 2019

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“…However, true mimicry of the multielectron reduction process still proves difficult because both cycles explain the sequence of reactions involved in biological dinitrogen reduction, on the one hand, but only a low yield catalytic reaction is observed in one of those systems, on the other hand. − The monometallic model systems of Chatt and Schrock cycles bind N 2 in an end-on manner and therefore lead to only weakly or moderately activated N 2 -intermediates, which might be the crucial factor for the absence of a catalytic reaction. The binding of N 2 in a side-on manner is usually accessed by homonuclear bimetallic complexes.…”

Section: Introductionmentioning

confidence: 99%

High-Pressure Synthesis and Characterization of Li₂Ca₃[N₂]₃—An Uncommon Metallic Diazenide with [N₂]^2–Ions

Schneider

Seibald

Deringer³

et al. 2013

J. Am. Chem. Soc.

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Dinitrogen (N2) ligation is a common and well-characterized structural motif in bioinorganic synthesis. In solid-state chemistry, on the other hand, homonuclear dinitrogen entities as structural building units proved existence only very recently. High-pressure/high-temperature (HP/HT) syntheses have afforded a number of binary diazenides and pernitrides with [N2](2–) and [N2](4–) ions, respectively. Here, we report on the HP/HT synthesis of the first ternary diazenide. Li2Ca3[N2]3 (space group Pmma, no. 51, a = 4.7747(1), b = 13.9792(4), c = 8.0718(4) Å, Z = 4, wRp = 0.08109) was synthesized by controlled thermal decomposition of a stoichiometric mixture of lithium azide and calcium azide in a multianvil device under a pressure of 9 GPa at 1023 K. Powder X-ray diffraction analysis reveals strongly elongated N–N bond lengths of dNN = 1.34(2)–1.35(3) Å exceeding those of previously known, binary diazenides. In fact, the refined N–N distances in Li2Ca3[N2]3 would rather suggest the presence of [N2](3·–) radical ions. Also, characteristic features of the N–N stretching vibration occur at lower wavenumbers (1260–1020 cm(–1)) than in the binary phases, and these assignments are supported by first-principles phonon calculations. Ultimately, the true character of the N2 entity in Li2Ca3[N2]3 is probed by a variety of complementary techniques, including electron diffraction, electron spin resonance spectroscopy (ESR), magnetic and electric conductivity measurements, as well as density-functional theory calculations (DFT). Unequivocally, the title compound is shown to be metallic containing diazenide [N2](2–) units according to the formula (Li(+))2(Ca(2+))3([N2](2–))3·(e(–))2.

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New developments in synthetic nitrogen fixation with molybdenum and tungsten phosphine complexes

Cited by 21 publications

References 72 publications

Free Reaction Enthalpy Profile of the Schrock Cycle Derived from Density Functional Theory Calculations on the Full [Mo^HIPTN₃N] Catalyst

Free Reaction Enthalpy Profile of the Schrock Cycle Derived from Density Functional Theory Calculations on the Full [Mo^HIPTN₃N] Catalyst

Molybdenum-Catalyzed Ammonia Formation Using Simple Monodentate and Bidentate Phosphines as Auxiliary Ligands

High-Pressure Synthesis and Characterization of Li₂Ca₃[N₂]₃—An Uncommon Metallic Diazenide with [N₂]^2–Ions

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New developments in synthetic nitrogen fixation with molybdenum and tungsten phosphine complexes

Cited by 21 publications

References 72 publications

Free Reaction Enthalpy Profile of the Schrock Cycle Derived from Density Functional Theory Calculations on the Full [MoHIPTN3N] Catalyst

Free Reaction Enthalpy Profile of the Schrock Cycle Derived from Density Functional Theory Calculations on the Full [MoHIPTN3N] Catalyst

Molybdenum-Catalyzed Ammonia Formation Using Simple Monodentate and Bidentate Phosphines as Auxiliary Ligands

High-Pressure Synthesis and Characterization of Li2Ca3[N2]3—An Uncommon Metallic Diazenide with [N2]2–Ions

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Free Reaction Enthalpy Profile of the Schrock Cycle Derived from Density Functional Theory Calculations on the Full [Mo^HIPTN₃N] Catalyst

Free Reaction Enthalpy Profile of the Schrock Cycle Derived from Density Functional Theory Calculations on the Full [Mo^HIPTN₃N] Catalyst

High-Pressure Synthesis and Characterization of Li₂Ca₃[N₂]₃—An Uncommon Metallic Diazenide with [N₂]^2–Ions