Phosphido-bridged Ta/Rh bimetallic complex: synthesis, structure, and catalytic hydrosilylation of acetophenone

Findlay, Andrea E.; Leelasubcharoen, Somying; Кузьмина, Л. Г.; Howard, Judith A. K.; Nikonov, Georgii I.

doi:10.1039/c0dt00141d

Cited by 15 publications

(8 citation statements)

References 42 publications

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“…This complex adds to the short list of well‐defined tantalum/rhodium heterobimetallic species and the surprisingly very limited list of NHC‐based early/late‐TM assemblies …”

Section: Resultsmentioning

confidence: 99%

Early/Late Heterobimetallic Tantalum/Rhodium Species Assembled Through a Novel Bifunctional NHC‐OH Ligand

Srivastava

Moneuse

Petit

et al. 2018

Chemistry A European J

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The straightforward synthesis of a new unsymmetrical hydroxy-tethered N-heterocyclic carbene (NHC) ligand, HL, is presented. The free ligand exhibits an unusual OH-carbene hydrogen-bonding interaction. This OH-carbene motif was used to yield 1) the first tantalum complex displaying both a Fischer- and Schrock-type carbene ligand and 2) a unique NHC-based early/late heterobimetallic complex. More specifically, the protonolysis chemistry between the ligand's hydroxy group and imido-alkyl or alkylidene-alkyl tantalum precursor complexes yielded the rare monometallic tantalum-NHC complexes [Ta(XtBu)(L)(CH tBu) ] (X=N, CH), in which the alkoxy-carbene ligand acts as a chelate. In contrast, HL only binds to rhodium through the NHC unit in [Rh(HL)(cod)Cl] (cod=cycloocta-1,5-diene), the hydroxy pendant arm remaining unbound. This bifunctional ligand scaffold successfully promoted the assembly of rhodium/tantalum heterobimetallic complexes upon either 1) the insertion of [Rh(cod)Cl] into the Ta-NHC bond in [Ta(NtBu)(L)(CH tBu) ] or 2) protonolysis between the free hydroxy group in [Rh(HL)(cod)Cl] and one alkyl group in [Ta(NtBu)(CH tBu) ].

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“…This complex adds to the short list of well‐defined tantalum/rhodium heterobimetallic species and the surprisingly very limited list of NHC‐based early/late‐TM assemblies …”

Section: Resultsmentioning

confidence: 99%

Early/Late Heterobimetallic Tantalum/Rhodium Species Assembled Through a Novel Bifunctional NHC‐OH Ligand

Srivastava

Moneuse

Petit

et al. 2018

Chemistry A European J

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“…The bond length of Ta–Rh (2.7807(11) Å) is slightly longer than the sum of the covalent radii of Ta and Rh, indicating a dative interaction from electron‐rich Rh to electron‐deficient Ta. [13] Because of the high coordination number for the Ta atom in complex 3 compared with that of 2 , the bond lengths of Ta–C(1) and Ta–C(4) (2.225(11) and 2.186(12) Å) are longer than those of complex 2 , while they are consistent with other metallacyclopentadiene‐bridged dinuclear Ta complexes. [14] The bond lengths of the C‐atom linkages in the tantalacyclopentadiene, C(1)–C(2), C(2)–C(3), and C(3)–C(4) bonds, are similar, and equalization of the C–C bonds agree with other dinuclear metallacyclopentadiene complexes …”

Section: Resultsmentioning

confidence: 99%

“…The Ir atom is coordinated by two P‐atoms of dppe; the dihedral angle of C(1)–Ir–C(4) and P(1)–Ir–P(2) planes is 20.4°, thus adapting a distorted five‐coordinated square pyramidal geometry around the Ir atom with Cl(4) at the apical position, which was structurally similar to (diene)IrCl(diphosphine) complexes. [16] The bond length of Ta–Ir (2.7415(11) Å) is comparable to that of complex 3 , while somewhat longer than the sum of the covalent radii of Ta and Ir,[13] indicating the presence of a dative interaction from the electron‐rich Ir to the electron‐deficient Ta. The heterobimetallic moiety of complex 6 , except for the dppe moiety, was very similar to complex 3 : the tantalacyclopentadiene moiety is almost flat with little deviation from the best plane.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Characterization of Heterobimetallic Tantalum–Rhodium and Tantalum–Iridium Complexes Connected by a Tantalacyclopentadiene Fragment

Yamamoto

Higashida

Nagae

et al. 2016

Helvetica Chimica Acta

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We report the synthesis of heterobimetallic Ta-Rh and Ta-Ir complexes bridged by a 2,5-di-tertbutyltantalacyclopentadiene fragment. A mononuclear 2,5-di-tert-butyltantalacyclopentadiene complex 2 was prepared by the reaction of (g 2 -Me 3 SiCCSiMe 3 )TaCl 3 (dme) (1) with excess amounts of 3,3-dimethylbut-1-yne in the presence of AlCl 3 . The tantalacyclopentadiene moiety of complex 2 served as a g 4 -diene unit for coordinating the Rh and Ir centers; treatment of 2 with [M(l-Cl)(cod)] 2 (M = Rh and Ir; cod = cycloocta-1,5-diene) in toluene gave TaRh(l-C 4 H 2 t Bu 2 )Cl 4 (cod) (3) and [TaIr(l-C 4 H 2 t Bu 2 )Cl 4 ] 2 (5), respectively. The X-Ray diffraction study of 3 revealed a dative bond from an electron-rich Rh toward an electron-deficient Ta. Upon dissolving 3 in THF, [(thf)TaRh(l-C 4 H 2 t Bu 2 ) Cl 3 ] 2 (l-Cl) 2 (4) was isolated together with free cycloocta-1,5-diene. When complex 5 was treated with 1,2-bis-(diphenylphosphino)ethane (dppe), a monomeric Ta-Ir complex, TaIr(l-C 4 H 2 t Bu 2 )Cl 4 (dppe) (6), was isolated. Ta-Rh and Ta-Ir heterobimetallic complexes 3 and 6 were reduced by a two-electron process upon reaction with 2,3,5,6tetramethyl-1,4-bis(trimethylsilyl)-1,4-dihydropyrazine (7a: Si-Me 4 -DHP) or 2,5-dimethyl-1,4-bis(trimethylsilyl)-1,4dihydropyrazine (7b: Si-Me 2 -DHP) to afford the corresponding complexes TaM(l-C 4 H 2 t Bu 2 )Cl 2 (L) (8: M = Rh, L = cod; 9: M = Ir, L = dppe), where the metallacycle moiety was assigned to have a tantalacyclopentadiene fragment with a large contribution of a tantalacyclopentatriene canonical form.Bu 2 )TaCl 3 (2), as a unique precursor for reacting with Rh and Ir cyclooctadiene complexes, giving the corresponding Ta-Rh and Ta-Ir heterobimetallic complexes. In these complexes, the diene moiety of the tantalacyclopentadiene served as the

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“…Cp 2 WH 2 was purchased from Alfa Aesar and used as received. The following compounds were prepared according to literature procedures: Cp 2 TaH 3 , 34 [RhCl(dippp)] 2 , 35 Ru(H)(Cl)(CO)(P i Pr 3 ) 2 , 36 Ru(H)(Cl)(N 2 )(P i Pr 3 ) 2 . 37 1 H, 31 P, and 13 C NMR spectra were recorded on a Bruker AV-300 MHz or AV-400 MHz spectrometer.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Anionic Tantalum Dihydride Complexes: Heterobimetallic Coupling Reactions and Reactivity toward Small-Molecule Activation

Ostapowicz

Fryzuk

2015

Inorg. Chem.

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The anionic dihydride complex [Cp2TaH2](-) was synthesized as a well-defined molecular species by deprotonation of Cp2TaH3 while different solubilizing agents, such as [2.2.2]cryptand and 18-crown-6, were applied to encapsulate the alkali-metal counterion. The ion pairs were characterized by multiple spectroscopic methods as well as X-ray crystallography, revealing varying degrees of interaction between the hydride ligands of the anion and the respective countercation in solution and in the solid state. The [Cp2TaH2](-) complex anion shows slow exchange of the hydride ligands when kept under a D2 atmosphere, but a very fast reaction is observed when [Cp2TaH2](-) is reacted with CO2, from which Cp2TaH(CO) is obtained as the tantalum-containing reaction product, along with inorganic salts. Furthermore, [Cp2TaH2](-) can act as a synthon in heterobimetallic coupling reactions with transition-metal halide complexes. Thus, the heterobimetallic complexes Cp2Ta(μ-H)2Rh(dippp) and Cp2Ta(μ-H)2Ru(H)(CO)(P(i)Pr3)2 were synthesized and characterized by various spectroscopies and via single-crystal X-ray diffraction. The new hydride bridged tantalum-rhodium heterobimetallic complex is cleaved under a CO atmosphere to yield mononuclear species and slowly exchanges protons and hydride ligands when exposed to D2 gas.

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Phosphido-bridged Ta/Rh bimetallic complex: synthesis, structure, and catalytic hydrosilylation of acetophenone

Cited by 15 publications

References 42 publications

Early/Late Heterobimetallic Tantalum/Rhodium Species Assembled Through a Novel Bifunctional NHC‐OH Ligand

Early/Late Heterobimetallic Tantalum/Rhodium Species Assembled Through a Novel Bifunctional NHC‐OH Ligand

Synthesis and Characterization of Heterobimetallic Tantalum–Rhodium and Tantalum–Iridium Complexes Connected by a Tantalacyclopentadiene Fragment

Anionic Tantalum Dihydride Complexes: Heterobimetallic Coupling Reactions and Reactivity toward Small-Molecule Activation

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