Principles of Dinitrogen Hydrogenation: Computational Insights

Musaev, Djamaladdin G.; Bobadova‐Parvanova, Petia; Morokuma, Keiji

doi:10.1002/9783527621965.ch4

Cited by 4 publications

(6 citation statements)

References 75 publications

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“…Thus, there is elongation of NN bond length in each N 2 adsorption configuration caused by transfer of electron from metal d states to the antibonding orbitals of N 2 , and the relationship between N 2 unit charge and NN bond length of six chemisorbed N 2 states is shown in Figure b. The activation of N 2 at the isolated Rh 1 Co 3 sites is consistent with the principles of dinitrogen hydrogenation …”

supporting

confidence: 67%

“…The activation of N 2 at the isolated Rh 1 Co 3 sites is consistent with the principles of dinitrogen hydrogenation. 15 H 2 absorbs dissociatively at Rh 1 Co 3 bimetallic sites (Rh site and Co 1 /Co 4 sites) and absorbs molecularly at sites far away from Rh 1 Co 3 bimetallic sites (Co 2 /Co 3 sites) as shown in Figure S3 and Table S2. The results indicate that the isolated Rh active center of Rh 1 Co 3 bimetallic site is efficient for the activation of H 2 to H active species.…”

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confidence: 99%

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Surface Single-Cluster Catalyst for N₂-to-NH₃ Thermal Conversion

et al. 2017

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The ammonia synthesis from N is of vital importance, with imitating biological nitrogen fixation attracted much interest. Herein, we investigate the catalytic mechanisms of N-to-NH thermal conversion on the singly dispersed bimetallic catalyst RhCo/CoO(011), and find that the preferred pathway is an associative mechanism analogous to the biological process, in which alternating hydrogenations of the N occur, with H activation on both metal sites. We propose that the singly dispersed bimetallic MA catalyst, in which the doped metal atom M substitutes an oxygen atom on the oxide surface of metal A, serves as a new surface single-cluster catalyst (SCC) design platform for the biomimetic N-to-NH thermal conversion. The catalytic ability of MA catalyst is attributed to both the charge buffer capacity of doped metal M and the complementary role of synergic metal A in catalysis. Our work provides insights and guidelines for further optimizing the MA catalyst.

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confidence: 67%

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confidence: 99%

Surface Single-Cluster Catalyst for N₂-to-NH₃ Thermal Conversion

et al. 2017

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“…Ta endothermically by 8.4 kcal/mol (see Figure 7). Then 3b C Ta is formed via H 5 Ta but not in 2b C Zr . Whether the hydrogenation occurs or not, the isomerization process in the ditantalum dinitrogen complex is much easier compared to the dizirconium dinitrogen complex in both Sitatype and Chirik-type ligands.…”

Section: Tamentioning

confidence: 99%

“…4b For N 2 to bind with a mononuclear TM, the side-on structure was found to be the only form for late TM complexes and the end-on coordination mode was seen in almost all existing mononuclear TM dinitrogen complexes. 5 The end-on bonding mode is more active in dinitrogen activation via the protonation-and-reduction (Chatt-type) mechanism. In binuclear TM complexes, however, the side-on coordination was predicted to be one of the major factors to convert dinitrogen into ammonia/hydrazine.…”

Section: ■ Introductionmentioning

confidence: 99%

“…(2) availability of HOMO and LUMO with appropriate symmetry; and (3) rigidity of the ligand environment. 5,6,8,9,11 On the other hand, Sita et al and Chirik et al 12 demonstrated with experimental evidence that end-on coordination can be a viable pathway as well for dinitrogen hydrogenation. A detailed study of N 2 hydrogenation triggered by bimetallic complexes with N 2 end-on coordination is still lacking.…”

Section: ■ Introductionmentioning

confidence: 99%

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Homolytic or Heterolytic Dihydrogen Splitting with Ditantalum/Dizirconium Dinitrogen Complexes? A Computational Study

Lei

Liu

2015

Organometallics

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Transition metal complexes play a key role in creating efficient molecular catalysis processes leading to the ammonia production from earth-abundant dinitrogen. It is indispensable to examine the mechanism and influence of transition metal complexes on dinitrogen hydrogenation. In this paper, the mechanism of the dinitrogen hydrogenation triggered by bimetallic complexes [L 2 M] 2 (μ-η 2 :η 2 -N 2 ) (M = Ta and Zr, L = Sita-type or Chirik-type ligand) is investigated by density functional theory calculation. Our results show that the side-on ditantalum dinitrogen complex with Sita-type ligands favors the pathway of homolytic dihydrogen splitting when hydrogenation products are generated. However, the dihydrogen splitting switches to the heterolytic pathway as the dominant mechanism when Zr is the metal center. The ditantalum dinitrogen complex undergoes hydrogenation much easier from the side-on coordination mode than the side-on-end-on mode with Sita-type or Chirik-type ligands. With these findings from the computational study, this work identifies that different metal centers and coligands (Sita-type or Chirik-type) in different binding modes (side-on-end-on or side-on bridged) dictate the pathway of dihydrogen cleavage triggered by the bimetallic complexes. This work should provide insights on factors impacting the dinitrogen hydrogenation process and shed light on designing new transition metals and ligands for dinitrogen hydrogenation catalysts in the future.

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Bis(cyclopentadienyl) Titanium Dinitrogen Chemistry: Synthesis and Characterization of a Side-on Bound Haptomer

et al. 2007

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The titanocene dinitrogen complex [(η 5 -C 5 H 2 -1,2,4-Me 3 ) 2 Ti] 2 (µ 2 ,η 2 ,η 2 -N 2 ) (1-N 2 ) has been prepared both by dihydrogen reductive elimination from the in situ generated monohydride derivative and by alkali metal reduction of the corresponding monoiodide. In the solid state, 1-N 2 contains a side-on bound N 2 ligand with an N-N bond length of 1.216(3) Å, consistent with a significant contribution from a two-electron-reduced diazenido ([N 2 ] 2-) fragment. Attempts to maintain side-on coordination of the N 2 ligand but increase the wedge dihedral by introducing isopropyl or tert-butyl substituents induced a change in hapticity to end-on and a less activated bridging dinitrogen ligand. The ansa-titanocene dinitrogen complexes rac-[Me 2 Si(η 5 -C 5 H 2 -2-SiMe 3 -4-t Bu) 2 Ti] 2 (µ 2 ,η 1 ,η 1 -N 2 ) (4-N 2 ) and [Me 2 Si(η 5 -C 5 Me 4 )(η 5 -C 5 H 3 -3-t Bu)Ti] 2 (µ 2 ,η 1 ,η 1 -N 2 ) (5-N 2 ) have also been prepared and crystallographically characterized and shown to have weakly activated, end-on dinitrogen ligands. The latter example coordinates two additional equivalents of N 2 upon cooling under a dinitrogen atmosphere in pentane solution.

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Principles of Dinitrogen Hydrogenation: Computational Insights

Cited by 4 publications

References 75 publications

Surface Single-Cluster Catalyst for N₂-to-NH₃ Thermal Conversion

Surface Single-Cluster Catalyst for N₂-to-NH₃ Thermal Conversion

Homolytic or Heterolytic Dihydrogen Splitting with Ditantalum/Dizirconium Dinitrogen Complexes? A Computational Study

Bis(cyclopentadienyl) Titanium Dinitrogen Chemistry: Synthesis and Characterization of a Side-on Bound Haptomer

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Principles of Dinitrogen Hydrogenation: Computational Insights

Cited by 4 publications

References 75 publications

Surface Single-Cluster Catalyst for N2-to-NH3 Thermal Conversion

Surface Single-Cluster Catalyst for N2-to-NH3 Thermal Conversion

Homolytic or Heterolytic Dihydrogen Splitting with Ditantalum/Dizirconium Dinitrogen Complexes? A Computational Study

Bis(cyclopentadienyl) Titanium Dinitrogen Chemistry: Synthesis and Characterization of a Side-on Bound Haptomer

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Surface Single-Cluster Catalyst for N₂-to-NH₃ Thermal Conversion

Surface Single-Cluster Catalyst for N₂-to-NH₃ Thermal Conversion