Browse
Submit Data
Databases
API
Help

Dataset Information

18 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

An iridium(iii/iv/v) redox series featuring a terminal imido complex with triplet ground state.

ABSTRACT: The iridium(iii/iv/v) imido redox series [Ir(NtBu){N(CHCHPtBu₂)₂}]^0/+/2+ was synthesized and examined spectroscopically, magnetically, crystallographically and computationally. The monocationic iridium(iv) imide exhibits an electronic doublet ground state with considerable 'imidyl' character as a result of covalent Ir-NtBu bonding. Reduction gives the neutral imide [Ir(NtBu){N(CHCHPtBu₂)₂}] as the first example of an iridium complex with a triplet ground state. Its reactivity with respect to nitrene transfer to selected electrophiles (CO₂) and nucleophiles (PMe₃), respectively, is reported.

SUBMITTER: Kinauer M

PROVIDER: S-EPMC5944377 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

An iridium(iii/iv/v) redox series featuring a terminal imido complex with triplet ground state.

Kinauer Markus M Diefenbach Martin M Bamberger Heiko H Demeshko Serhiy S Reijerse Edward J EJ Volkmann Christian C Würtele Christian C van Slageren Joris J de Bruin Bas B Holthausen Max C MC Schneider Sven S

Chemical science 20180417 18

The iridium(iii/iv/v) imido redox series [Ir(NtBu){N(CHCHPtBu2)2}]0/+/2+ was synthesized and examined spectroscopically, magnetically, crystallographically and computationally. The monocationic iridium(iv) imide exhibits an electronic doublet ground state with considerable 'imidyl' character as a result of covalent Ir-NtBu bonding. Reduction gives the neutral imide [Ir(NtBu){N(CHCHPtBu2)2}] as the first exa ...[more]

PMID: 29780564

Similar Datasets

A Pair of Cobalt(III/IV) Terminal Imido Complexes.

Project description:The reaction of the cobalt(I) complex [(TIMMNmes )CoI ](BPh4 ) (2) (TIMMNmes =tris-[2-(3-mesitylimidazolin-2-ylidene)methyl]amine) with 1-adamantylazide yields the cobalt(III) imido complex [(TIMMNmes )CoIII (NAd)](BPh4 ) (3) with concomitant release of dinitrogen. The N-anchor in diamagnetic 3 features an unusual, planar tertiary amine, which results from repulsive electrostatic interaction with the filled d(z2 )-orbital of the cobalt ion and negative hyperconjugation with the neighboring methylene groups. One-electron oxidation of 3 with [FeCp2 ](OTf) provides access to the rare, high-valent cobalt(IV) imido complex [(TIMMNmes )CoIV (NAd)](OTf)2 (4). Despite a half-life of less than 1 h at room temperature, 4 could be isolated at low temperatures in analytically pure form. Single-crystal X-ray diffractometry and EPR spectroscopy corroborate the molecular structure and the d5 low-spin, S= 1/2 , electron configuration. A computational analysis of 4 suggests high covalency within the CoIV =NAd bond with non-negligible spin density located at the imido moiety, which translates into substantial triplet nitrene character.

| S-EPMC8362208 | biostudies-literature

Cubane-type Co4S4 clusters: synthesis, redox series, and magnetic ground states.

Project description:The recent demonstration that the carbene cluster [Fe(4)S(4)(Pr(i)(2)NHCMe(2))(4)] (9) is an accurate structural and electronic analogue of the fully reduced cluster of the iron protein of Azotobacter vinelandii nitrogenase, including a common S = 4 ground state, raises the issue of the existence and magnetism of other [M(4)S(4)L(4)](z) clusters, none of which are known with transition metals other than iron. The system CoCl(2)/Pr(i)(3)P/(Me(3)Si)(2)S/THF assembles [Co(4)S(4)(PPr(i)(3))(4)] (3), which is converted to [Co(4)S(4)(Pr(i)(2)NHCMe(2))(4)] (5) upon reaction with carbene. The clusters support the redox series [3](1-/0/1+) and [5](0/1+/2+); monocations (4, 6) have been isolated by chemical oxidation. Redox potentials and substitution reactions indicate that the carbene is the more effective electron donor to tetrahedral Fe(II) and Co(II) sites. Clusters 3-6 have the same overall cubane-type geometry as 9. Neutral clusters 3 and 5 have an S = 3 ground state. As with the S = 4 state of 9 with local spins S(Fe) = 2, the septet spin state can be described in terms of the coupling of three parallel and one antiparallel spins S(Co) = 3/2. The octanuclear clusters [Co(8)S(8)(PPr(i)(3))(6)](0,1+) were isolated as minor byproducts of the formation and chemical oxidation of 3. The clusters exhibit a rhomb-bridged noncubane (RBNC) structure, whereas clusters with the Fe(8)S(8) core possess edge-bridged double-cubane (EBDC) stereochemistry. There are two structural solutions for the M(8)S(8) core in the form of topological isomers whose stability may depend on valence electron count. A conceptual model for the RBNC <--> EBDC interconversion is presented. (Pr(i)(2)NHCMe(2) = C(11)H(20)N(2) = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene).

| S-EPMC3170832 | biostudies-literature

Redox Non-Innocent Behavior of a Terminal Iridium Hydrazido(2-) Triple Bond.

Project description:The synthesis of the first terminal Group 9 hydrazido(2-) complex, Cp*IrN(TMP) (6) (TMP=2,2,6,6-tetramethylpiperidine) is reported. Electronic structure and X-ray diffraction analysis indicate that this complex contains an Ir-N triple bond, similar to Bergman's seminal Cp*Ir(Nt Bu) imido complex. However, in sharp contrast to Bergman's imido, 6 displays remarkable redox non-innocent reactivity owing to the presence of the Nβ lone pair. Treatment of 6 with MeI results in electron transfer from Nβ to Ir prior to oxidative addition of MeI to the iridium center. This behavior opens the possibility of carrying out facile oxidative reactions at a formally IrIII metal center through a hydrazido(2-)/isodiazene valence tautomerization.

| S-EPMC5392362 | biostudies-literature

A full set of iridium(iv) pyridine-alkoxide stereoisomers: highly geometry-dependent redox properties.

Project description:We introduce and characterize the complete set of possible isomers of IrIV(pyalk)2Cl2 (pyalk = 2-(pyridin-2-yl)propan-2-oate), providing valuable insights on the properties of Ir(iv) species. The pyridine alkoxide ligand strongly stabilizes high oxidation states, essential to accessing the catalytically relevant Ir(iv) state, and results in robust complexes that can be handled under ambient conditions, even permitting chromatographic separation. The redox properties are isomer-dependent, spanning a 300 mV range, rationalized with ligand-field theory and DFT calculations. The reported complexes exhibit very high kinetic inertness against isomerization, despite highly disparate predicted thermodynamic stabilities, presenting a unique opportunity to study all five possible isomeric complexes with the same ligand set.

| S-EPMC5364517 | biostudies-literature

Carbon-hydrogen bond activation, C-N bond coupling, and cycloaddition reactivity of a three-coordinate nickel complex featuring a terminal imido ligand.

Project description:The three-coordinate imidos (dtbpe)Ni?NR (dtbpe = (t)Bu2PCH2CH2P(t)Bu2, R = 2,6-(i)Pr2C6H3, 2,4,6-Me3C6H2 (Mes), and 1-adamantyl (Ad)), which contain a legitimate Ni-N double bond as well as basic imido nitrogen based on theoretical analysis, readily deprotonate HC?CPh to form the amide acetylide species (dtbpe)Ni{NH(Ar)}(C?CPh). In the case of R = 2,6-(i)Pr2C6H3, reductive carbonylation results in formation of the (dtbpe)Ni(CO)2 along with the N-C coupled product keteneimine PhCH?C?N(2,6- (i)Pr2C6H3). Given the ability of the Ni?N bond to have biradical character as suggested by theoretical analysis, H atom abstraction can also occur in (dtbpe)Ni?N{2,6-(i)Pr2C6H3} when this species is treated with HSn((n)Bu)3. Likewise, the microscopic reverse reaction--conversion of the Ni(I) anilide (dtbpe)Ni{NH(2,6-(i)Pr2C6H3)} to the imido (dtbpe)Ni?N{2,6-(i)Pr2C6H3}--is promoted when using the radical Mes*O(•) (Mes* = 2,4,6-(t)Bu3C6H2). Reactivity studies involving the imido complexes, in particular (dtbpe)Ni?N{2,6-(i)Pr2C6H3}, are also reported with small, unsaturated molecules such as diphenylketene, benzylisocyanate, benzaldehyde, and carbon dioxide, including the formation of C-N and N-N bonds by coupling reactions. In addition to NMR spectroscopic data and combustion analysis, we also report structural studies for all the cycloaddition reactions involving the imido (dtbpe)Ni?N{2,6-(i)Pr2C6H3}.

| S-EPMC4269405 | biostudies-literature

Synthesis and characterization of an f-block terminal parent imido [U?NH] complex: a masked uranium(IV) nitride.

Project description:Deprotonation of [U(Tren(TIPS))(NH2)] (1) [Tren(TIPS) = N(CH2CH2NSiPr(i)3)3] with organoalkali metal reagents MR (M = Li, R = Bu(t); M = Na-Cs, R = CH2C6H5) afforded the imido-bridged dimers [{U(Tren(TIPS))(?-N[H]M)}2] [M = Li-Cs (2a-e)]. Treatment of 2c (M = K) with 2 equiv of 15-crown-5 ether (15C5) afforded the uranium terminal parent imido complex [U(Tren(TIPS))(NH)][K(15C5)2] (3c), which can also be viewed as a masked uranium(IV) nitride. The uranium-imido linkage was found to be essentially linear, and theoretical calculations suggested ?(2)?(4) polarized U-N multiple bonding. Attempts to oxidize 3c to afford the neutral uranium terminal parent imido complex [U(Tren(TIPS))(NH)] (4) resulted in spontaneous disproportionation to give 1 and the uranium-nitride complex [U(Tren(TIPS))(N)] (5); this reaction is a new way to prepare the terminal uranium-nitride linkage and was calculated to be exothermic by -3.25 kcal mol(-1).

| S-EPMC4353020 | biostudies-literature

Thermally and Magnetically Robust Triplet Ground State Diradical.

Project description:High spin ( S = 1) organic diradicals may offer enhanced properties with respect to several emerging technologies, but typically exhibit low singlet triplet energy gaps and possess limited thermal stability. We report triplet ground state diradical 2 with a large singlet-triplet energy gap, Δ EST ≥ 1.7 kcal mol-1, leading to nearly exclusive population of triplet ground state at room temperature, and good thermal stability with onset of decomposition at ∼160 °C under inert atmosphere. Magnetic properties of 2 and the previously prepared diradical 1 are characterized by SQUID magnetometry of polycrystalline powders, in polystyrene glass, and in other matrices. Polycrystalline diradical 2 forms a novel one-dimensional (1D) spin-1 ( S = 1) chain of organic radicals with intrachain antiferromagnetic coupling of J'/ k = -14 K, which is associated with the N···N and N···O intermolecular contacts. The intrachain antiferromagnetic coupling in 2 is by far strongest among all studied 1D S = 1 chains of organic radicals, which also makes 1D S = 1 chains of 2 most isotropic, and therefore an excellent system for studies of low-dimensional magnetism. In polystyrene glass and in frozen benzene or dibutyl phthalate solution, both 1 and 2 are monomeric. Diradical 2 is thermally robust and is evaporated under ultrahigh vacuum to form thin films of intact diradicals on silicon substrate, as demonstrated by X-ray photoelectron spectroscopy. Based on C-K NEXAFS spectra and AFM images of the ∼1.5 nm thick films, the diradical molecules form islands on the substrate with molecules stacked approximately along the crystallographic a-axis. The films are stable under ultrahigh vacuum for at least 60 h but show signs of decomposition when exposed to ambient conditions for 7 h.

| S-EPMC6472266 | biostudies-literature

A Terminal Imido Complex of an Iron-Sulfur Cluster.

Project description:We report the synthesis and characterization of the first terminal imido complex of an Fe-S cluster, (IMes)3 Fe4 S4 =NDipp (2; IMes=1,3-dimesitylimidazol-2-ylidene, Dipp=2,6-diisopropylphenyl), which is generated by oxidative group transfer from DippN3 to the all-ferrous cluster (IMes)3 Fe4 S4 (PPh3 ). This two-electron process is achieved by formal one-electron oxidation of the imido-bound Fe site and one-electron oxidation of two IMes-bound Fe sites. Structural, spectroscopic, and computational studies establish that the Fe-imido site is best described as a high-spin Fe3+ center, which is manifested in its long Fe-N(imido) distance of 1.763(2) Å. Cluster 2 abstracts hydrogen atoms from 1,4-cyclohexadiene to yield the corresponding anilido complex, demonstrating competency for C-H activation.

| S-EPMC8294340 | biostudies-literature

Oncosis-inducing cyclometalated iridium(iii) complexes.

Project description:Oncosis is a non-apoptotic form of programmed cell death (PCD), which differs from apoptosis in both morphological changes and inner pathways, and might hold the key to defeating a major obstacle in cancer therapy - drug-resistance, which is often a result of the intrinsic apoptosis resistance of tumours. However, despite the fact that the term "oncosis" was coined and used much earlier than apoptosis, little effort has been made to discover new drugs which can initiate this form of cell death, in comparison to drugs inducing apoptosis or any other type of PCD. So herein, we present the synthesis of a series of mitochondria-targeting cyclometalated Ir(iii) complexes, which activated the oncosis-specific protein porimin and calpain in cisplatin-resistant cell line A549R, and determined their cytotoxicity against a wide range of drug-resistant cancer types. To the best of our knowledge, these complexes are the very first metallo-components to induce oncosis in drug-resistant cancer cells.

| S-EPMC6000986 | biostudies-literature

(tert-Butyl-imido)bis-(η-cyclo-penta-dien-yl)pyridine-zirconium(IV).

Project description:The title compound, [Zr(C(5)H(5))(2)(C(4)H(9)N)(C(5)H(5)N)], was obtained from the reaction of (C(5)H(5))(2)Zr(py)(η(2)-Me(3)SiC(2)SiMe(3)) (py is pyridine) and (t)BuN=C=N(t)Bu alongside the formation of (C(5)H(5))(2)Zr(CN(t)Bu)(η(2)-Me(3)SiC(2)SiMe(3)). The zirconium atom is coordinated in a distorted tetra-hedral geometry by two cyclo-penta-dienyl ligands, a pyridine ligand, and a tert-butyl-imido ligand via a Zr=N double bond. The tert-butyl group is disordered over two positions in a 0.634 (5):0.366 (5) ratio.

| S-EPMC3007953 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data