(η4-Cycloocta-1,5-diene)(2-pyridinethiolato N-oxide-κO,κS)iridium(I)

Theron, M.; Purcell, Walter; Basson, S. S.

doi:10.1107/s0108270195008729

Cited by 3 publications

(3 citation statements)

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“…This leads to two short Ir–C olefin ( trans to chloride) and two longer Ir–C olefin ( trans to NHC) bond distances due to the differences in trans influence of the halogeno and the NHC ligands. The Ir–C COD distances range from 2.087(9) to 2.197(6) Å, and these values fall in the range reported for related IR-cod complexes. − The Ir–Cl1 bond length is also close to values reported for this separation in the literature. , (Table ). The two chloride ligands and the two nitrogen atoms from the phenanthroline (phen) donor form an approximately square-planar polyhedron around the palladium atom of 6 , which lies 0.008(2) Å out of the least-squares plane defined by the atoms N3, N4, Cl2, and Cl3.…”

Section: Resultssupporting

confidence: 74%

Heterobimetallic Complexes Bridged by Imidazol{[4,5-f][1,10]-phenanthrolin}-2-ylidene: Synthesis and Catalytic Activity in Tandem Reactions

et al. 2019

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A series of monometallic complexes obtained by metalation of the phenanthrolin donor in 1, 3-dibutyl-1H-imidazol[4,5-f ][1,10]phenanthrolin}ium hexafluorophospate 1 (M = Pd 2, Ru 3, Ir 4) have been prepared. Subsequently, the imidazolium moiety of complexes 2−4 was metalated with M′, leading to the heterobimetallic phenanthroline/NHC complexes (M/M′ = Pd/Rh 5, Pd/Ir 6, Pd/ Ru 7, Ru/Pd 8, Ir/Pd 9) and the homobimetallic complex (M/M′ = Ir/Ir 10). The new complexes were characterized by elemental analysis, FTIR, UV−vis, and NMR spectroscopy. The molecular structures of the heterobimetallic complexes 5 and 6 were determined by X-ray diffraction studies. The catalytic activity of the heterobimetallic complexes 5−9 were tested in selected tandem reactions (dehalogenation/transfer hydrogenation and Suzuki−Miyaura coupling/transfer hydrogenation). It was found that the M/M′ heterobimetallic complexes display higher catalytic activities when compared to equimolar mixtures of the mononuclear complexes M and M′, thus indicating that an increase in the number of metal atoms in one complex leads to an increased activity in the tandem reactions.

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Section: Resultssupporting

confidence: 74%

Heterobimetallic Complexes Bridged by Imidazol{[4,5-f][1,10]-phenanthrolin}-2-ylidene: Synthesis and Catalytic Activity in Tandem Reactions

et al. 2019

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“…The growth of crystals of 5 was accomplished by preparing a saturated solution of the complex in pentane and storing in a glovebox freezer at −25 °C. Structural characterization of 5 represents a rare example of an iridium complex with a bound N -oxide (Figure ). , The iridium–oxygen bond length of the coordinated N -oxide is 2.111 Å, which is comparable to the rhodium–oxygen bond length of a coordinated pyridine N -oxide (2.080 Å) in a [Rh(cycloocta-1,5-diene)(μ-pyridinyl N -oxide)] 2 dimer (the analogous distances in the two reported square-planar Ir(I) complexes were 2.031 and 2.030 Å) . The octahedral geometry of 5 and the seven-membered metallacycle with a coordinated N -oxide are unique for iridium.…”

Section: Resultsmentioning

confidence: 92%

Oxygen Atom Transfer to a Half-Sandwich Iridium Complex: Clean Oxidation Yielding a Molecular Product

et al. 2014

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The oxidation of [Ir(Cp*)(phpy)(NCAr(F))][B(Ar(F))4] (1; Cp* = η(5)-pentamethylcyclopentadienyl, phpy = 2-phenylene-κC(1')-pyridine-κN, NCAr(F) = 3,5-bis(trifluoromethyl)benzonitrile, B(Ar(F))4 = tetrakis[3,5-bis(trifluoromethyl)phenyl]borate) with the oxygen atom transfer (OAT) reagent 2-tert-butylsulfonyliodosobenzene (sPhIO) yielded a single, molecular product at -40 °C. New Ir(Cp*) complexes with bidentate ligands derived by oxidation of phpy were synthesized to model possible products resulting from oxygen atom insertion into the iridium-carbon and/or iridium-nitrogen bonds of phpy. These new ligands were either cleaved from iridium by water or formed unreactive, phenoxide-bridged iridium dimers. The reactivity of these molecules suggested possible decomposition pathways of Ir(Cp*)-based water oxidation catalysts with bidentate ligands that are susceptible to oxidation. Monitoring the [Ir(Cp*)(phpy)(NCAr(F))](+) oxidation reaction by low-temperature NMR techniques revealed that the reaction involved two separate OAT events. An intermediate was detected, synthesized independently with trapping ligands, and characterized. The first oxidation step involves direct attack of the sPhIO oxidant on the carbon of the coordinated nitrile ligand. Oxygen atom transfer to carbon, followed by insertion into the iridium-carbon bond of phpy, formed a coordinated organic amide. A second oxygen atom transfer generated an unidentified iridium species (the "oxidized complex"). In the presence of triphenylphosphine, the "oxidized complex" proved capable of transferring one oxygen atom to phosphine, generating phosphine oxide and forming an Ir-PPh3 adduct in 92% yield. The final Ir-PPh3 product was fully characterized.

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“…However, cyclometallated Ir(III) complexes containing external N-oxide groups on heterocyclic ligands have not been extensively structurally characterized, with one reported example describing a TEMPO radical [12]. More commonly, Ir(III) complexes involving a heterocyclic N-oxide ligand coordinate via the oxygen atom of the N-oxide group [13][14][15][16][17][18][19]. The tendency to coordinate the oxygen atom of a heterocyclic N-oxide group is generally favored in most transition metal complexes [20][21][22][23], largely due to the hardness of the N-oxide as a donor.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Crystallographic Characterization of Heteroleptic Ir(III) Complexes Containing the N-oxide Functional Group and Crystallographic Characterization of Ir(III) N-oxide Precursors

Stumbo,

Hodge,

Williams

et al. 2024

Crystals

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The N-oxide functional group has been exploited for synthetic strategies and drug design, and it has been utilized in imaging agents. Herein, we present rare examples of neutral heteroleptic cyclometallated Ir(III) compounds that contain an uncoordinated N-oxide functional group. These species, along with others described within, were verified by NMR, EA, HRMS, and single-crystal X-ray analysis. N-oxide-containing Ir(III) species were prepared selectively in high yields > 66% from chloro-bridged Ir(III) dimers with Acipimox, a picolinate-type ligand containing the N-oxide functional group. Non-N-oxide analogs were synthesized in a similar fashion (yields > 77%). Electrochemical comparison (cyclic voltammetry) indicates that the presence of an N-oxide functional group anodically shifts the reduction potential, suggesting that the N-oxide is acting as an electron-withdrawing group in these species. Crystallographic studies were pursued to examine the coordination behavior of these N-oxides compared to their non-oxidized congeners. The Ir(III) complexes with Acipimox indeed leave the N-oxide uncoordinated and exposed on the complexes. The uncoordinated N-oxide group is influential in directing the packing structures of these complexes directly through C-H···O and O···π interactions at the N-oxide. The crystallographic characterization of cationic Ir(III) compounds with uncoordinated nitrogen atoms is also presented. The C-H···N interactions between these complexes form a variety of dimers, finite chains, and continuous chains. Future work will focus on functionalizing the cationic Ir(III) species into their corresponding N-oxide derivatives and rigorously characterizing how the N-oxide functional group impacts the optical properties of transition metal compounds in both cationic and neutral complexes.

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(η4-Cycloocta-1,5-diene)(2-pyridinethiolato N-oxide-κO,κS)iridium(I)

Cited by 3 publications

References 4 publications

Heterobimetallic Complexes Bridged by Imidazol{[4,5-f][1,10]-phenanthrolin}-2-ylidene: Synthesis and Catalytic Activity in Tandem Reactions

Heterobimetallic Complexes Bridged by Imidazol{[4,5-f][1,10]-phenanthrolin}-2-ylidene: Synthesis and Catalytic Activity in Tandem Reactions

Oxygen Atom Transfer to a Half-Sandwich Iridium Complex: Clean Oxidation Yielding a Molecular Product

Synthesis and Crystallographic Characterization of Heteroleptic Ir(III) Complexes Containing the N-oxide Functional Group and Crystallographic Characterization of Ir(III) N-oxide Precursors

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