ChemInform Abstract: Synthesis, Reactivity, Molecular Structure, and Catalytic Activity of the Novel Dichlorodihydridoosmium(IV) Complexes OsH2Cl2(PR3)2 (PR3: P‐ iPr3, PMe‐tBu2).

Aracama, M.; Esteruelas, Miguel A.; Lahoz, Fernando J.; López, Jörge A.; Meyer, U.; Oro, Luis A.; Werner, Helmut

doi:10.1002/chin.199120246

Cited by 6 publications

(8 citation statements)

References 1 publication

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“…Complex OsH6(P i Pr3)2 (1) was prepared according to the published method. 36 Instrumental methods used for characterization, X-ray information, and computational details are given in the Supporting Information. Chemical shifts (in ppm) are referenced to residual solvent peaks ( 1 H, 13 C{ 1 H}), external H3PO4 ( 31 P{ 1 H}), or BF3•OEt2 ( 11 B).…”

Section: Methodsmentioning

confidence: 99%

Reduction of Benzonitriles via Osmium–Azavinylidene Intermediates Bearing Nucleophilic and Electrophilic Centers

et al. 2019

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The reduction of the N-C triple bond of benzonitriles promoted by OsH6(P i Pr3)2 (1) has been studied. Complex 1 releases a H2 molecule and coordinates 2,6-dimethylbenzonitrile to afford the tetrahydride OsH4{κ 1-N-(NCC6H3Me2)}(P i Pr3)2 (2), which is thermally stable towards the insertion of the nitrile into one of the Os-H bonds. In contrast to 2,6-dimethylbenzonitrile, benzonitrile and 2-methylbenzonitrile undergo insertion, via Os(η 2-NCR) intermediates, to give the azavinylidene derivatives OsH3(=N=CC6H4R)(P i Pr3)2 (R = H (3), Me (4)). The analysis by means of computational tools (EDA-NOCV) of the bonding situation in these compounds suggests that the donor-acceptor nature of the osmium azavinylidene bond dominates over the mixed electron-sharing/donor-acceptor and pure electron-sharing bonding modes. The N atom is strongly nucleophilic whereas one of the hydrides is electrophilic. In spite of the different nature of these centers, the migration of the latter to the N atom is kinetically prevented. However, the use of water as a proton shuttle allows the hydride migration, as a consequence of a significant decrease of the activation barrier. The resulting phenylaldimine intermediates evolve by means of orthometalation to give OsH3{κ 2-N,C-(NH=CHC6H3R)}(P i Pr3)2 (R = H (5), Me (6)). The presence of electrophilic and nucleophilic centers in 3 confers it ability to activate σ-bonds, including H2 and pinacolborane (HBpin). The reaction with the latter gives OsH3{κ 2-N,C-[N(Bpin)=CHC6H4]}(P i Pr3)2 (7). Supporting Information. The following files are available free of charge. General information, crystallographic data, computational details, NMR and IR spectra (PDF) Cartesian coordinates of calculated structures (XYZ) Accession Codes CCDC 1907065-1907067 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing data_

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Section: Methodsmentioning

confidence: 99%

Reduction of Benzonitriles via Osmium–Azavinylidene Intermediates Bearing Nucleophilic and Electrophilic Centers

et al. 2019

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“…The dihydride compound OsH 2 Cl(Bcat)(P i Pr 3 ) 2 (20) is initially formed, as a result of the homolytic addition of the B-H bond to the osmium atom of A. Complex 20 reacts with a second molecule oh HBcat to give the hydride-bis(boryl) derivative OsHCl(Bcat) 2 (P i Pr 3 ) 2 (21) and molecular hydrogen. 31 Amineboranes undergo dehydrogenation in the presence of A to form aminoboranes.…”

Section: B-h Bond Activationmentioning

confidence: 99%

“…In the beginning, the structure of OsH 2 Cl 2 (P i Pr 3 ) 2 was viewed as a distorted square antiprism of ideal D 4d symmetry with two vacant coordination sites. 21 Later, it was described as a bicapped tetrahedron and as a trigonal prism. 22 The structure of OsH 3 Cl(P i Pr 3 ) 2 has essentially C 2v symmetry.…”

Section: Introductionmentioning

confidence: 99%

Sigma-bond activation reactions induced by unsaturated Os(IV)-hydride complexes

Esteruelas

Oliván

Oñate

2020

Advances in Organometallic Chemistry

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“…Complex 1 was prepared according to the published method. 28 Nitriles were purchased from commercial sources and distilled in a Kugelrohr distillation oven. NMR spectra were recorded on a Bruker ARX 300, Bruker Avance 300 MHz, or a Bruker Avance 400 MHz instruments.…”

Section: Methodsmentioning

confidence: 99%

Dihydroboration of Alkyl Nitriles Catalyzed by an Osmium-Polyhydride: Scope, Kinetics, and Mechanism

et al. 2020

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Complex OsH6(P i Pr3)2 is an efficient catalyst precursor for the addition of pinacolborane and catecholborane to the C-N triple bond of alkyl nitriles. In this way, a variety of N,N-diborylamines have been isolated and fully characterized, including thirteen derivatives not described so far. The range of nitriles used is wide and comprises substrates having unfunctionalized linear and branched chains, and functionalized chains with methoxide, trifluoromethyl, aryl, pyridyl, benzoyl, or cyanide groups. Kinetic studies demonstrate that the overall process consists of two consecutive irreversible reactions: the catalytic metal-promoted monohydroboration of the nitrile to afford the borylimine and the metal-free stoichiometric hydroboration of the latter to give the diborylamine. The mechanism of the hydroboration has been established by combining the kinetic analysis of the catalysis, stoichiometric reactions, and DFT calculations. The rate determining step of the catalysis is the insertion of the C-N triple bond of the nitrile into the Os-B bond of an osmium-σ-borane intermediate and is regio-directed by the nucleophilicity of the nitrogen atom and the electrophilicity of the carbon atom of the nitrile.

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ChemInform Abstract: Synthesis, Reactivity, Molecular Structure, and Catalytic Activity of the Novel Dichlorodihydridoosmium(IV) Complexes OsH2Cl2(PR3)2 (PR3: P‐ iPr3, PMe‐tBu2).

Cited by 6 publications

References 1 publication

Reduction of Benzonitriles via Osmium–Azavinylidene Intermediates Bearing Nucleophilic and Electrophilic Centers

Reduction of Benzonitriles via Osmium–Azavinylidene Intermediates Bearing Nucleophilic and Electrophilic Centers

Sigma-bond activation reactions induced by unsaturated Os(IV)-hydride complexes

Dihydroboration of Alkyl Nitriles Catalyzed by an Osmium-Polyhydride: Scope, Kinetics, and Mechanism

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