Thermal and Photochemical Reactions of Azidoruthenium(III) Complexes of Macrocyclic Tertiary Amines and the Structure of the (Phosphoraniminato)ruthenium(III) Complex trans‐[Ru(14‐TMC)(N3)(NPPh3)]+

Ho, Chi Ming; Leung, H.; Wu, Shui Xing; Low, Kam‐Hung; Lin, Zhenyang; Ming, Chi

doi:10.1002/ejic.201100771

Cited by 8 publications

(4 citation statements)

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“…There was no detectable difference between the final pressure after 4 h of photolysis of 1 in CH 2 Cl 2 under a dinitrogen atmosphere either with or without the presence of 100 equiv of acrylamide, a known azide radical scavenger (Figure S7). − We therefore propose that room temperature photolysis does not generate azide radical and that any nitrogen formed in this process is made via the formation of 2 and its bimolecular coupling.…”

Section: Resultsmentioning

confidence: 99%

Formation of the N≡N Triple Bond from Reductive Coupling of a Paramagnetic Diruthenium Nitrido Compound

et al. 2022

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Construction of nitrogen−nitrogen triple bonds via homocoupling of metal nitrides is an important fundamental reaction relevant to a potential Nitrogen Economy.Here, we report that room temperature photolysis of Ru 2 (chp) 4 N 3 (chp − = 2-chloro-6hydroxypyridinate) in CH 2 Cl 2 produces N 2 via reductive coupling of Ru 2 (chp) 4 N nitrido species. Computational analysis reveals that the nitride coupling transition state (TS) features an out-of-plane "zigzag" geometry instead of the anticipated planar zigzag TS. However, with intentional exclusion of dispersion correction, the planar zigzag TS geometry can also be found. Both the out-of-plane and planar zigzag TS geometries feature two important types of orbital interactions: (1) donor−acceptor interactions involving intermolecular donation of a nitride lone pair into an empty Ru−N π* orbital and (2) Ru−N π to Ru−N π* interactions derived from coupling of nitridyl radicals. The relative importance of these two interactions is quantified both at and after the TS. Our analysis shows that both interactions are important for the formation of the N−N σ bond, while radical coupling interactions dominate the formation of N−N π bonds. Comparison is made to isoelectronic Ru 2 -oxo compounds. Formation of an O−O bond via bimolecular oxo coupling is not observed experimentally and is calculated to have a much higher TS energy. The major difference between the nitrido and oxo systems stems from an extremely large driving force, ∼−500 kJ/mol, for N−N coupling vs a more modest driving force for O−O coupling, −40 to −140 kJ/mol.

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Section: Resultsmentioning

confidence: 99%

Formation of the N≡N Triple Bond from Reductive Coupling of a Paramagnetic Diruthenium Nitrido Compound

et al. 2022

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“…72. d MANNIA = trans-[Ru(TMC)(NC–O–OCH 3 –C 6 H 4 )(N 3 )] + , MANNOG = trans-[Ru(TMC)(Ph 3 PN)(N 3 )] + , MANNUM = trans-[Ru(TMC)(NCC 6 H 5 )(N 3 )] + , from ref. 73. e [Ru(N4Py)(N 3 )] + , from ref. 74. f [Ru(o-BQDI)(Me 3 tacn)(N 3 )] + , from ref.…”

Section: Figurementioning

confidence: 99%

“… d MANNIA = trans-[Ru(TMC)(NC–O–OCH 3 –C 6 H 4 )(N 3 )] + , MANNOG = trans-[Ru(TMC)(Ph 3 PN)(N 3 )] + , MANNUM = trans-[Ru(TMC)(NCC 6 H 5 )(N 3 )] + , from ref. 73. …”

Section: Figurementioning

confidence: 99%

Synthesis, characterization and solution behavior of a systematic series of pentapyridyl-supported Ru^II complexes: comparison to bimetallic analogs

Park

Berry

2017

Dalton Trans.

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A series of Ru complexes stabilized with the pentapyridyl ligand PyMe (PyMe = 2,6-bis(1,1-bis(2-pyridyl)ethyl)pyridine) and with an axial X ligand (X = Cl, HO, N, MeCN) were prepared and characterized in the solid state and in non-aqueous solution. The cyclic voltammograms of these complexes in MeCN reflect a reversible substitution of the axial X ligand with MeCN. Irreversible ligand substitution of [(PyMe)RuN] is also observed in propylene carbonate, but only at oxidizing potentials that decompose the azide ligand. The monometallic chloride and azide species are compared with analogous Ru metal-metal bonded complexes, which have been reported to undergo irreversible chloride dissociation upon reduction.

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“…Phosphinimines are an underutilized class of ligands for late-transition metals that are beginning to receive more and more attention, especially as chelating donors for catalytic applications . Monodentate phosphinimines, however, are quite rare on ruthenium, whereas monodentate phosphinimide complexes are a bit more common. − Moreover, while phosphinimides have been utilized in early transition-metal-based alkyne metathesis, to the best of our knowledge, phosphinimines and phosphinimides have not been used in ruthenium-based OM catalysts. What makes these ligands so intriguing is their unique electronic structure; they can act as both strong σ- and π-donors due to their ylide-like structure. , Therefore, it was thought that phosphinimines and/or phosphinimides would be well suited for stabilizing high oxidation state, coordinatively unsaturated ruthenium carbene complexes that are common intermediates during OM.…”

Section: Introductionmentioning

confidence: 99%

Ruthenium Phosphinimine Complex as a Fast-Initiating Olefin Metathesis Catalyst with Competing Catalytic Cycles

2022

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A ruthenium-based olefin metathesis (OM) catalyst bearing a monodentate triphenylphosphinimine ligand, Ru1, was synthesized, characterized, and its activity for the homocoupling of terminal alkenes was investigated. Utilizing 1-hexene as a model substrate, the empirical rate law for Ru1 was found to be first-order in alkene and complex (indicating that both species were involved in the rate-limiting step), with a rate constant of 0.697 ± 0.050 M–1 s–1. Moreover, the experimentally determined activation parameters ΔS ⧧ and ΔH ⧧ (−48.7 ± 5.1 eu and 3.19 ± 0.15 kcal/mol, respectively) were consistent with an associative or associative interchange ligand substitution reaction. When considering the ΔG ⧧ (298 K) value of 17.7 kcal/mol, Ru1 ranked among the fastest initiating ruthenium-based OM catalysts reported in the literature. Density functional theory (DFT) calculations were also performed to explore potential catalytic mechanisms. Two pathways were considered: a traditional mechanism where the phosphinimine ligand de-coordinated and an alternative mechanism where the phosphine donor de-coordinated. Although the energy differences between the two pathways were typically fairly small (1.4–3.5 kcal/mol), the alternative pathway with phosphine de-coordination was energetically more favorable. It is anticipated, however, that both cycles are working in tandem during the catalytic reaction. In addition to kinetic studies, the stability of Ru1 was explored using 1-hexene as a model substrate. The phosphinimine catalyst was found to be mildly oxygen-sensitive and moisture-tolerant. Furthermore, Ru1 was determined to be prone to bimolecular decomposition, through the crystallographic characterization of a key degradation product. There was also strong evidence for NH exchange between the tricyclohexylphosphine and triphenylphosphinimine moieties. Lastly, the substrate scope of Ru1 in regard to α-olefins was explored. Catalytic efficiency dropped with more electron-deficient alkenes, as well as with increasing steric bulk on the substrate, which was consistent with the proposed catalytic mechanism.

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Thermal and Photochemical Reactions of Azidoruthenium(III) Complexes of Macrocyclic Tertiary Amines and the Structure of the (Phosphoraniminato)ruthenium(III) Complex trans‐[Ru(14‐TMC)(N₃)(NPPh₃)]⁺

Abstract: The bis(azido)ruthenium (III) complexes, trans-[Ru(L)

Cited by 8 publications

References 35 publications

Formation of the N≡N Triple Bond from Reductive Coupling of a Paramagnetic Diruthenium Nitrido Compound

Formation of the N≡N Triple Bond from Reductive Coupling of a Paramagnetic Diruthenium Nitrido Compound

Synthesis, characterization and solution behavior of a systematic series of pentapyridyl-supported Ru^II complexes: comparison to bimetallic analogs

Ruthenium Phosphinimine Complex as a Fast-Initiating Olefin Metathesis Catalyst with Competing Catalytic Cycles

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Thermal and Photochemical Reactions of Azidoruthenium(III) Complexes of Macrocyclic Tertiary Amines and the Structure of the (Phosphoraniminato)ruthenium(III) Complex trans‐[Ru(14‐TMC)(N3)(NPPh3)]+

Abstract: The bis(azido)ruthenium (III) complexes, trans-[Ru(L)

Cited by 8 publications

References 35 publications

Formation of the N≡N Triple Bond from Reductive Coupling of a Paramagnetic Diruthenium Nitrido Compound

Formation of the N≡N Triple Bond from Reductive Coupling of a Paramagnetic Diruthenium Nitrido Compound

Synthesis, characterization and solution behavior of a systematic series of pentapyridyl-supported RuII complexes: comparison to bimetallic analogs

Ruthenium Phosphinimine Complex as a Fast-Initiating Olefin Metathesis Catalyst with Competing Catalytic Cycles

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Product

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Thermal and Photochemical Reactions of Azidoruthenium(III) Complexes of Macrocyclic Tertiary Amines and the Structure of the (Phosphoraniminato)ruthenium(III) Complex trans‐[Ru(14‐TMC)(N₃)(NPPh₃)]⁺

Synthesis, characterization and solution behavior of a systematic series of pentapyridyl-supported Ru^II complexes: comparison to bimetallic analogs