<i>cis</i>-Oxoruthenium complexes supported by chiral tetradentate amine (N<sub>4</sub>) ligands for hydrocarbon oxidations

Tse, Chun‐Wai; Liu, Yungen; Chow, Toby Wai-Shan; Ma, Chaoqun; Yip, Wing-Ping; Chang, Xiaoyong; Low, Kam‐Hung; Huang, Jie‐Sheng; Che, Chi‐Ming

doi:10.1039/c7sc05224c

Cited by 13 publications

(10 citation statements)

References 108 publications

(64 reference statements)

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“…With the optimal conditions in hand, we further applied this protocol to prepare the new hexadentate ligands which were hard to synthesize using the traditional strategy . First, the primary diamines with various substituents were examined under the optimal conditions (see Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Switching the Photoreactions of Ir(III) Diamine Complexes between C–N Coupling and Dehydrogenation under Visible Light Irradiation

Huang

Zhou

et al. 2022

Inorg. Chem.

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The selective photoreactions under mild conditions play an important role in synthetic chemistry. Herein, efficient and mild protocols for switching the photoreactions of Ir(III)-diamine complexes between the interligand C–N coupling and dehydrogenation are developed in the presence of O2 in EtOH solution. The photoreactions of achiral diamine complexes rac-[Ir(L)2(dm)](PF6) (L is 2-phenylquinoline or 2-(2,4-difluorophenyl)quinoline, dm is 1,2-ethylenediamine, 1,2-diaminopropane, 2-methyl-1,2-diamino-propane, or N,N′-dimethyl-1,2-ethylenediamine) are competitive in the oxidative C–N coupling and dehydrogenation at room temperature, which can be switched into the interligand C–N coupling reaction at 60 °C, affording hexadentate complexes in good to excellent yields, or the dehydrogenative reaction in the presence of a catalytic amount of TEMPO as an additive, affording imine complexes. Mechanism studies reveal that 1O2 is the major reactive oxygen species, and metal aminyl is the key intermediate in the formation of the oxidative C–N coupling and imine products in the photoreaction processes. These will provide a new and practical protocol for the synthesis of multidentate and imine ligands in situ via the postcoordinated strategy under mild conditions.

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Section: Resultsmentioning

confidence: 99%

Switching the Photoreactions of Ir(III) Diamine Complexes between C–N Coupling and Dehydrogenation under Visible Light Irradiation

Huang

Zhou

et al. 2022

Inorg. Chem.

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“…Quinoline is an important structural motif in natural products and functional materials. , In particular, 8-aminoquinolines are important motifs in biological activities, − ligands used in coordination chemistry and catalysis in C–H functionalization . However, the traditional synthesis protocol of 8-aminoquinolines is nitration of quinoline under strongly acidic conditions.…”

Section: Introductionmentioning

confidence: 99%

Visible-Light-Induced Amination of Quinoline at the C8 Position via a Postcoordinated Interligand-Coupling Strategy under Mild Conditions

Peng

Chen

et al. 2021

Inorg. Chem.

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The postcoordinated interligand-coupling strategy provides a useful and complementary protocol for synthesizing polydentate ligands. Herein, diastereoselective photoreactions of Λ-[Ir(pq)2(d-AA)] (Λ-d ) and Λ-[Ir(pq)2(l-AA)] (Λ-l , where pq is 2-phenylquinoline and AA is an amino acid) are reported in the presence of O2 under mild conditions. Diastereomer Λ-d is dehydrogenatively oxidized into an imino acid complex, while diastereomer Λ-l mainly occurs via interligand C–N cross-dehydrogenative coupling between quinoline at the C8 position and AA ligands at room temperature, affording Λ-[Ir(pq)(l-pq-AA)]. Furthermore, the photoreaction of diastereomer Λ-l is temperature-dependent. Mechanistic experiments reveal the ligand–radical intermediates may be involved in the reaction. Density functional theory calculations were used to eluciate the origin of diastereoselectivity and temperature dependence. This will provide a new protocol for the amination of quinoline at the C8 position via the postcoordinated interligand C–N cross-coupling strategy under mild conditions.

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“…As shown in Figure , the Soret band underwent a 4 nm blue-shift, accompanied by a similar blue-shift in the Q-band. Such changes in the UV–vis spectra have been attributed to the generation of oxidatively active Ru IV O species during epoxidation. − …”

Section: Resultsmentioning

confidence: 99%

Cerium(IV) Sulfate as a Cocatalyst for Promoting the Direct Epoxidation of Propylene by Ruthenium Porphyrin with Molecular Oxygen

Zhou

et al. 2020

Ind. Eng. Chem. Res.

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The direct epoxidation of propylene to propylene oxide (PO) using molecular oxygen is difficult to achieve. Liquid-phase aerobic propylene epoxidation has been achieved using metalloporphyrin catalysts, but the efficiency was poor. Herein, the direct aerobic epoxidation of propylene was accomplished using ruthenium porphyrin with Ce(SO 4 ) 2 as a cocatalyst. The propylene conversion and PO selectivity were 33.7% and 82.3%, respectively. The efficiency was approximately 2 times higher than RuTPP (ruthenium mesotetraphenylporphyrin) alone and more than 3 times higher than Ce(SO 4 ) 2 alone. Ce(IV) promoted the formation of allyl radicals and promoted the oxidative cleavage of the CC bond of propylene.

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cis-Oxoruthenium complexes supported by chiral tetradentate amine (N₄) ligands for hydrocarbon oxidations

Abstract: We report the first examples of cis-dioxo ruthenium(vi) complexes supported by chiral N4 ligands and their stoichiometric and catalytic reactivities with alkanes and alkenes.

Cited by 13 publications

References 108 publications

Switching the Photoreactions of Ir(III) Diamine Complexes between C–N Coupling and Dehydrogenation under Visible Light Irradiation

Switching the Photoreactions of Ir(III) Diamine Complexes between C–N Coupling and Dehydrogenation under Visible Light Irradiation

Visible-Light-Induced Amination of Quinoline at the C8 Position via a Postcoordinated Interligand-Coupling Strategy under Mild Conditions

Cerium(IV) Sulfate as a Cocatalyst for Promoting the Direct Epoxidation of Propylene by Ruthenium Porphyrin with Molecular Oxygen

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cis-Oxoruthenium complexes supported by chiral tetradentate amine (N4) ligands for hydrocarbon oxidations

Abstract: We report the first examples of cis-dioxo ruthenium(vi) complexes supported by chiral N4 ligands and their stoichiometric and catalytic reactivities with alkanes and alkenes.

Cited by 13 publications

References 108 publications

Switching the Photoreactions of Ir(III) Diamine Complexes between C–N Coupling and Dehydrogenation under Visible Light Irradiation

Switching the Photoreactions of Ir(III) Diamine Complexes between C–N Coupling and Dehydrogenation under Visible Light Irradiation

Visible-Light-Induced Amination of Quinoline at the C8 Position via a Postcoordinated Interligand-Coupling Strategy under Mild Conditions

Cerium(IV) Sulfate as a Cocatalyst for Promoting the Direct Epoxidation of Propylene by Ruthenium Porphyrin with Molecular Oxygen

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cis-Oxoruthenium complexes supported by chiral tetradentate amine (N₄) ligands for hydrocarbon oxidations