Some molecular hydrogen complexes of iridium

Crabtree, Robert H.; Lavin, Maryellen; Bonneviot, Laurent

doi:10.1021/ja00274a030

Cited by 236 publications

(153 citation statements)

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“…As 1 equiv of HY was added to the solution of 1 and 2 in CD 2 Cl 2 , the 1 H NMR spectra showed the disappearance of the signals between −6.95 and −5.54 ppm of the hydride ligands and the appearance of a new signal at about 4.6 ppm, which decreased on shaking and was attributed to free H 2 . 25 No new signals attributable to a η 2 -H 2 complex 26 formed by protonation were observed in the spectra, according to the reaction shown in Scheme 2.…”

Section: ■ Results and Discussionmentioning

confidence: 95%

Azo Complexes of Osmium(II): Preparation and Reactivity of Organic Azide and Hydrazine Derivatives

et al. 2013

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Section: ■ Results and Discussionmentioning

confidence: 95%

Azo Complexes of Osmium(II): Preparation and Reactivity of Organic Azide and Hydrazine Derivatives

et al. 2013

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“…In order to obtain further information, we increased the temperature of the sample and observed no change in the profile of the spectra until Ϫ10°C. At this temperature a signal at δ ϭ 4.58 ppm due [20] to free H 2 appears in the 1 H NMR spectra, which increases in intensity with time with the simultaneous lowering of all the other signals. The 31 P NMR spectra also show a decrease in the intensity of the A 2 B multiplet and the formation of decomposition products near Ϫ10°C.…”

Section: Protonation Reactionsmentioning

confidence: 95%

New Nitrosylrhenium Hydrides as Precursors of “Diazo” Complexes: Preparation of Hydrazine and Diazene Derivatives

et al. 2004

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“…Such reactivity is of interest with regard to the reaction chemistry of the products of dehydrogenation. [30,31] Results and Discussion Amine-borane s-complexes and dehydrogenation to aminoboranes: Addition of A to a C 6 H 5 F solution of [Ir- [32,33] (where Ar…”

Section: H T U N G T R E N N U N G (Pcy 3 ) 2 (H) 2 -A C H T U N G T mentioning

confidence: 99%

[Ir(PCy₃)₂(H)₂(H₂BNMe₂)]⁺ as a Latent Source of Aminoborane: Probing the Role of Metal in the Dehydrocoupling of H₃B⋅NMe₂H and Retrodimerisation of [H₂BNMe₂]₂

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Chaplin

et al. 2011

Chemistry A European J

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The Ir(III) fragment {Ir(PCy(3))(2)(H)(2)}(+) has been used to probe the role of the metal centre in the catalytic dehydrocoupling of H(3)B⋅NMe(2)H (A) to ultimately give dimeric aminoborane [H(2)BNMe(2)](2) (D). Addition of A to [Ir(PCy(3))(2)(H)(2)(H(2))(2)][BAr(F)(4)] (1; Ar(F) = (C(6)H(3)(CF(3))(2)), gives the amine-borane complex [Ir(PCy(3))(2)(H)(2)(H(3)B⋅NMe(2)H)][BAr(F)(4)] (2 a), which slowly dehydrogenates to afford the aminoborane complex [Ir(PCy(3))(2)(H)(2)(H(2)B-NMe(2))][BAr(F)(4)] (3). DFT calculations have been used to probe the mechanism of dehydrogenation and show a pathway featuring sequential BH activation/H(2) loss/NH activation. Addition of D to 1 results in retrodimerisation of D to afford 3. DFT calculations indicate that this involves metal trapping of the monomer-dimer equilibrium, 2 H(2)BNMe(2) ⇌ [H(2)BNMe(2)](2). Ruthenium and rhodium analogues also promote this reaction. Addition of MeCN to 3 affords [Ir(PCy(3))(2)(H)(2)(NCMe)(2)][BAr(F)(4)] (6) liberating H(2)B-NMe(2) (B), which then dimerises to give D. This is shown to be a second-order process. It also allows on- and off-metal coupling processes to be probed. Addition of MeCN to 3 followed by A gives D with no amine-borane intermediates observed. Addition of A to 3 results in the formation of significant amounts of oligomeric H(3)B⋅NMe(2)BH(2)⋅NMe(2)H (C), which ultimately was converted to D. These results indicate that the metal is involved in both the dehydrogenation of A, to give B, and the oligomerisation reaction to afford C. A mechanism is suggested for this latter process. The reactivity of oligomer C with the Ir complexes is also reported. Addition of excess C to 1 promotes its transformation into D, with 3 observed as the final organometallic product, suggesting a B-N bond cleavage mechanism. Complex 6 does not react with C, but in combination with B oligomer C is consumed to eventually give D, suggesting an additional role for free aminoborane in the formation of D from C.

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Some molecular hydrogen complexes of iridium

Cited by 236 publications

References 3 publications

Azo Complexes of Osmium(II): Preparation and Reactivity of Organic Azide and Hydrazine Derivatives

Azo Complexes of Osmium(II): Preparation and Reactivity of Organic Azide and Hydrazine Derivatives

New Nitrosylrhenium Hydrides as Precursors of “Diazo” Complexes: Preparation of Hydrazine and Diazene Derivatives

[Ir(PCy₃)₂(H)₂(H₂BNMe₂)]⁺ as a Latent Source of Aminoborane: Probing the Role of Metal in the Dehydrocoupling of H₃B⋅NMe₂H and Retrodimerisation of [H₂BNMe₂]₂

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Some molecular hydrogen complexes of iridium

Cited by 236 publications

References 3 publications

Azo Complexes of Osmium(II): Preparation and Reactivity of Organic Azide and Hydrazine Derivatives

Azo Complexes of Osmium(II): Preparation and Reactivity of Organic Azide and Hydrazine Derivatives

New Nitrosylrhenium Hydrides as Precursors of “Diazo” Complexes: Preparation of Hydrazine and Diazene Derivatives

[Ir(PCy3)2(H)2(H2BNMe2)]+ as a Latent Source of Aminoborane: Probing the Role of Metal in the Dehydrocoupling of H3B⋅NMe2H and Retrodimerisation of [H2BNMe2]2

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[Ir(PCy₃)₂(H)₂(H₂BNMe₂)]⁺ as a Latent Source of Aminoborane: Probing the Role of Metal in the Dehydrocoupling of H₃B⋅NMe₂H and Retrodimerisation of [H₂BNMe₂]₂