The stereochemistry of the oxidation of diamines and of the reduction of diimines in the coordination sphere of ruthenium(II)

Jandrasics, Erik; Kolp, Brunhilde; Wolny, Juliusz A.; Zelewsky, Alex von

doi:10.1016/s0020-1693(97)05938-0

Cited by 12 publications

(6 citation statements)

References 26 publications

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“…The mass spectrometry (MS) analysis showed an intense peak at m / z 728.52 ([M + H] + ), which was also pointed to the dehydrogenative oxidation product Δ-[Ir(pq) 2 (hpro-2H 2 )]. This indicates that the Δ-[Ir(pq) 2 ( l -hpro)] diastereomer is converted to Δ-[Ir(pq) 2 (hpro-2H 2 )] under the reaction conditions, consistent with the previous observations. ,− …”

Section: Resultsmentioning

confidence: 95%

Discrepancy between Proline and Homoproline in Chiral Recognition and Diastereomeric Photoreactivity with Iridium(III) Complexes

Xiong

Peng

Zhang³

et al. 2021

Inorg. Chem.

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The chiral-recognition processes of homoproline (hpro) and [Ir-(pq) 2 (MeCN) 2 ](PF 6 ) (pq is 2-phenylquinoline; MeCN is acetonitrile) are investigated, in favor of formation of the thermodynamically stable diastereomers Λ-[Ir(pq) 2 (D-hpro)] and Δ-[Ir(pq) 2 (L-hpro)]. Moreover, the diastereoselective photoreactions of Δ-[Ir(pq) 2 (D-hpro)] and Δ-[Ir(pq) 2 (L-hpro)] are reported in the presence of O 2 at room temperature. Diastereomer Δ-[Ir(pq) 2 (L-hpro)] is dehydrogenatively oxidized into imino acid complex Δ-[Ir(pq) 2 (hpro-2H 2 )] (hpro-2H 2 is 3,4,5,6-tetrahydropicalinate), while diastereomer Δ-[Ir(pq) 2 (D-hpro)] occurs by interligand C−N cross-coupling and dehydrogenative oxidation reactions, affording three products: Δ-[Ir(pq)(D-pqh)] [pqh is N-(2-phenylquinolin-8-yl)homoproline], Δ-[Ir(pq) 2 (hpro-2H 2 )], and Δ-[Ir(pq) 2 (D-hpro-2H 6 )] [hpro-2H 6 is 2,3,4,5-tetrahydropicalinate]. The C−N cross-coupling and dehydrogenative oxidation reactions are competitive, and the dehydrogenative oxidation reactions are regioselective. By optimization of the photoreaction parameters such as the diastereomeric substrate, solvent, and temperature as well as base, each possible competitive product is selectively controlled. In addition, density functional theory calculations are performed to elucidate the distinctly chiral recognition between proline and hpro with an iridium(III) complex.

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Section: Resultsmentioning

confidence: 95%

Discrepancy between Proline and Homoproline in Chiral Recognition and Diastereomeric Photoreactivity with Iridium(III) Complexes

Xiong

Peng

Zhang³

et al. 2021

Inorg. Chem.

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“…This is much different from the previous report in [Ru(bpy) 2 (dmen)] 2+ , where only the imine complex [Ru(bpy) 2 (dmdiim)] 2+ was reported. 20 The results demonstrate that the primary and secondary diamines are suitable for the coupling with the quinoline ring in situ. Subsequently, we paid our attention to the pq ligand.…”

Section: Synthesis Of Hexadentate Complexes Via the Interligand C−n C...mentioning

confidence: 84%

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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“…In addition, the two carbon atoms in the ethylenediamine backbone can adopt two conformations, λ or δ, Scheme . Based upon NMR findings39, 40 the configuration Δ( S,S )/Λ( R,R ) was assigned to the diastereomer with the highest concentration in solution regardless of the conformation of the ethylenediamine. Our DFT calculations predict that Δ( S,S,λ )/Λ( R,R,δ ) configurations due to the less steric strain are more stable than Δ( R,R,λ )/Λ( S,S,δ ) by 2.2 kcal/mol in the gas phase.…”

Section: Resultsmentioning

confidence: 99%

A theoretical study on the exciton circular dichroism of propeller‐like metal complexes of bipyridine and tripodal tris(2‐pyridylmethyl)amine derivatives

Fan

Ziegler

2010

Chirality

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Time-dependent density functional theory (TD-DFT) has been employed to simulate the circular dichroism (CD) spectra of bipyridyl ruthenium(II) complexes as well as zinc(II) and copper(II) complexes containing tris(2-pyridylmethyl)amine (TPA) derivatives. A qualitative model is used to account for the mechanism by which the bis- and tris-bipyridine complexes (or analogous systems) exhibit exciton CD. The model is further used to predict the sign of the exciton CD bands. The predictions are in agreement with experiment and DFT calculations. A comprehensive analysis is presented of the subtle differences in the CD spectra of this series of related complexes.

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The stereochemistry of the oxidation of diamines and of the reduction of diimines in the coordination sphere of ruthenium(II)

Cited by 12 publications

References 26 publications

Discrepancy between Proline and Homoproline in Chiral Recognition and Diastereomeric Photoreactivity with Iridium(III) Complexes

Discrepancy between Proline and Homoproline in Chiral Recognition and Diastereomeric Photoreactivity with Iridium(III) Complexes

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

A theoretical study on the exciton circular dichroism of propeller‐like metal complexes of bipyridine and tripodal tris(2‐pyridylmethyl)amine derivatives

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