Group 4 Transition Metal–Dinitrogen Complexes

Seino, Hidetake; Kajita, Yuji

doi:10.1002/9783527344260.ch2

Cited by 6 publications

(1 citation statement)

References 150 publications

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“…One of the most successful applications of bulky bis(amido) ligands is olefin polymerizations . For example, titanium complexes bearing a bis(amido) ligand with 2,6-disubstituted phenyl groups are used for the polymerization of various α-olefins. , Moreover, group 4 transition-metal complexes with multidentate poly(amido) ligands catalyze the hydroamination of alkynes, allenes, and alkenes. ,,,,, Recently, the reduction of dinitrogen to ammonia has been accomplished using a titanium catalyst carrying a tris(amido)amine ligand, albeit that several dinitrogen-coordinated complexes of group 4 transition metals have been known for more than two decades …”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structures, and Solution Dynamics of Titanium and Zirconium Complexes Carrying a Bis(indolyl) and Two Diethylamido Ligands

et al. 2019

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Indolyl is the anionic species obtained from the deprotonation of the N–H group of indole. Group 4 transition-metal complexes that carry indolyl-based polydentate ligands represent promising homogeneous catalysts for, e.g., olefin polymerization, hydroamination, and nitrogen-fixation reactions due to the weak π-donation and electron-withdrawing properties, as well as the low basicity of indolyl. In this study, we systematically investigated the synthesis and structures of titanium and zirconium complexes that carry deprotonated 2,2′-bis(indolyl)methane ligands (henceforth: bis(indolyl) ligands) and two diethylamido ligands. We found that the coordination geometry of the indolyl nitrogen atom in such bis(indolyl) ligands is affected by the steric impact of the substituents attached to the central aromatic ring. Moreover, we examined the dynamics of such bis(indolyl) ligands in solution for the corresponding zirconium complexes, and the mechanism was discussed in conjunction with DFT calculations. The results of this study suggest that bis(indolyl) ligands may also serve as coordinatively flexible ancillary ligands, and indicate the feasibility of an expansion from bis(indolyl) to bis(indolyl)-donor ligands.

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Section: Introductionmentioning

confidence: 99%

Synthesis, Structures, and Solution Dynamics of Titanium and Zirconium Complexes Carrying a Bis(indolyl) and Two Diethylamido Ligands

et al. 2019

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Dinitrogen Binding at a Trititanium Chloride Complex and Its Conversion to Ammonia under Ambient Conditions

et al. 2022

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Reaction of [TiCp*Cl 3 ] (Cp* = η 5 -C 5 Me 5 ) with one equivalent of magnesium in tetrahydrofuran at room temperature affords the paramagnetic trinuclear complex [{TiCp*(μ-Cl)} 3 (μ 3 -Cl)], which reacts with dinitrogen under ambient conditions to give the diamagnetic derivative [{TiCp*(μ-Cl)} 3 (μ 3 -η 1 : η 2 : η 2 -N 2 )] and the titanium(III) dimer [{TiCp*Cl(μ-Cl)} 2 ]. The structure of the trinuclear mixed-valence complexes has been studied by experimental and theoretical methods and the latter compound represents the first well-defined example of the μ 3 -η 1 : η 2 : η 2 coordination mode of the dinitrogen molecule. The reaction of [{TiCp*(μ-Cl)} 3 (μ 3η 1 : η 2 : η 2 -N 2 )] with excess HCl in tetrahydrofuran results in clean NH 4 Cl formation with regeneration of the starting material [TiCp*Cl 3 ]. Therefore, a cyclic ammonia synthesis under ambient conditions can be envisioned by alternating N 2 /HCl atmospheres in a [TiCp*Cl 3 ]/Mg(excess) reaction mixture in tetrahydrofuran.

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Dinitrogen Binding at a Trititanium Chloride Complex and Its Conversion to Ammonia under Ambient Conditions

et al. 2022

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Reaction of [TiCp*Cl3] (Cp*=η5‐C5Me5) with one equivalent of magnesium in tetrahydrofuran at room temperature affords the paramagnetic trinuclear complex [{TiCp*(μ‐Cl)}3(μ3‐Cl)], which reacts with dinitrogen under ambient conditions to give the diamagnetic derivative [{TiCp*(μ‐Cl)}3(μ3‐η1 : η2 : η2‐N2)] and the titanium(III) dimer [{TiCp*Cl(μ‐Cl)}2]. The structure of the trinuclear mixed‐valence complexes has been studied by experimental and theoretical methods and the latter compound represents the first well‐defined example of the μ3‐η1 : η2 : η2 coordination mode of the dinitrogen molecule. The reaction of [{TiCp*(μ‐Cl)}3(μ3‐η1 : η2 : η2‐N2)] with excess HCl in tetrahydrofuran results in clean NH4Cl formation with regeneration of the starting material [TiCp*Cl3]. Therefore, a cyclic ammonia synthesis under ambient conditions can be envisioned by alternating N2/HCl atmospheres in a [TiCp*Cl3]/Mg(excess) reaction mixture in tetrahydrofuran.

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Group 4 Transition Metal–Dinitrogen Complexes

Cited by 6 publications

References 150 publications

Synthesis, Structures, and Solution Dynamics of Titanium and Zirconium Complexes Carrying a Bis(indolyl) and Two Diethylamido Ligands

Synthesis, Structures, and Solution Dynamics of Titanium and Zirconium Complexes Carrying a Bis(indolyl) and Two Diethylamido Ligands

Dinitrogen Binding at a Trititanium Chloride Complex and Its Conversion to Ammonia under Ambient Conditions

Dinitrogen Binding at a Trititanium Chloride Complex and Its Conversion to Ammonia under Ambient Conditions

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