Selective Dehydrogenation of Amines with Respect to Coordination Geometry:  Different Oxidation Products of Tricyano[bis(2-pyridylmethyl)amine]ferrate(II) between mer- and fac-Isomers

Goto, Masafumi; Koga, Norimitsu; Ohse, Yasuhiko; Kudoh, Yuka; Kukihara, Michiko; Okuno, Yoshinori; Kurosaki, Hiromasa

doi:10.1021/ic035289a

Cited by 19 publications

(35 citation statements)

References 32 publications

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“…In 1983, Keene et al reported that Δ-[Ru(bpy) 2 ( R -Meampy)] 2+ and Λ-[Ru(bpy) 2 ( S -Meampy)] 2+ [Meampy is 2-(1-aminoethy1)pyridine] diastereomers have different oxidation rates under chemo- and electro-oxidation conditions . Twenty years later, Kurosaki et al found that only the mer -[Fe(2-DPA)(CN) 3 ] − [2-DPA is bis(2-pyridylmethyl)amine] isomer was oxidized into the imine complex in the presence of ammonium peroxodisulflate as an oxidant . Inspired by these findings, we have observed the photoreaction of Δ-[Ir(pq) 2 ( d -pro)] and Δ-[Ir(pq) 2 ( l -pro)] diastereomers and found the oxidation dehydrogenation rate of Δ-[Ir(pq) 2 ( l -pro)] is ∼60 times faster than that of Δ-[Ir(pq) 2 ( d -pro)] .…”

Section: Results and Discussionmentioning

confidence: 66%

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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Section: Results and Discussionmentioning

confidence: 66%

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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“…On the basis of the previous findings that the photoreactions of AA complexes are diastereoselective at room temperature, ,,− the diastereomeric complexes of hpro were prepared by the reaction of enantiopure Δ-[Ir(pq) 2 (MeCN) 2 ](PF 6 ) with d -hpro or l -hpro. The photoreactivity of Δ-[Ir(pq) 2 ( l -hpro)] was indeed observed using EtOH as the solvent in the presence of an O 2 atmosphere at 30 °C, as shown in Scheme .…”

Section: Resultsmentioning

confidence: 99%

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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“…also found only the mer ‐[Fe II (2‐ DPA)(CN) 3 ] – (2‐DPA is bis(2‐pyridylmethyl)amine) isomer was oxidized into imine complex in the presence of (NH 4 ) 2 S 2 O 8 as an oxidant, while the fac ‐[Fe II (2‐DPA)(CN) 3 ] – was converted into fac ‐[Fe III (2‐DPA)(CN) 3 ] under the identical conditions, indicating the geometrical isomerism also significantly influences the oxidative reaction. [ 13 ] Inspired by these findings, we have turned our attention to Ir(III) amino acid (AA) complexes and found that the diastereomers have distinguishable photophysical properties and photoreactivity. [ 14 ] The oxidative dehydrogenation rate of Δ‐[Ir(pq) 2 ( L ‐pro)] ( Δ‐ L , where pq is 2‐phenylquinoline and pro is proline) diastereomer is significantly faster than that of Δ‐[Ir(pq) 2 ( D ‐pro)] ( Δ‐ D ) diastereomer in the presence of O 2 with a blue light irradiation.…”

Section: Background and Originality Contentmentioning

confidence: 99%

Diastereoselective Photoreaction of Ir(III) Amine Complexes for Generation of New Multidentate Ligands in situ via a Postcoordinated Interligand‐Coupling Strategy

Chen

Yao

et al. 2021

Chin. J. Chem.

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Main observation and conclusion The diastereoselective photoreactions of Ir(III)‐amine and Ir(III)‐diamine complexes are observed in the presence of O2. The Ʌ‐[Ir(pq)2(R‐mapy)](PF6) (pq is 2‐phenylquinoline and mapy is 2‐(1‐aminoethyl)pyridine) diastereomer is dehydrogenatively oxidized into imine complex Ʌ‐[Ir(pq)2(mapy‐2H)](PF6) at room temperature, while the Ʌ‐[Ir(pq)2(S‐mapy)](PF6) diastereomer occurs interligand C—N cross‐coupling reaction at 60 °C, affording a new tetradentate complex Ʌ‐[Ir(pq)(S‐pqpe)] (PF6) (pqpe is 2‐phenyl‐N‐(1‐pyridin‐2‐yl)ethyl‐quinolin‐8‐amine). The identical cases are also observed in diamine complexes Ʌ‐[Ir(pq)2(R,R‐chda)](PF6) (chda is 1,2‐diaminocyclohexane), Ʌ‐[Ir(pq)2(R,S‐chda)](PF6), and Ʌ‐[Ir(pq)2(S,S‐chda)](PF6), where the R configuration ligand is dehydrogenatively oxidized into imine, while the S configuration is retentive and the bound nitrogen atom is coupling to the C8 of pq ligand, affording Ʌ‐[Ir(pq)2(chdi)](PF6) (chdi is 1,2‐diiminocyclohexane), Ʌ‐[Ir(pq)(S‐pqchim)](PF6) (pqchim is N‐(2‐iminocyclohexyl)‐2‐phenyl‐ quinolin‐8‐amine), and Ʌ‐[Ir(S,S‐pqchda)](PF6) (pqchda is N',N”‐bis(2‐phenylquinolin‐8‐yl)cyclohexane‐1,2‐diamine), respectively. These provide a new and useful protocol for the synthesis of multidentate ligands in situ via the postcoordinated interligand‐coupling strategy under mild conditions.

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Selective Dehydrogenation of Amines with Respect to Coordination Geometry: Different Oxidation Products of Tricyano[bis(2-pyridylmethyl)amine]ferrate(II) between mer- and fac-Isomers

Cited by 19 publications

References 32 publications

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

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

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

Diastereoselective Photoreaction of Ir(III) Amine Complexes for Generation of New Multidentate Ligands in situ via a Postcoordinated Interligand‐Coupling Strategy

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