Hydridorhodathiaboranes: Synthesis, Characterization, and Reactivity

Álvarez, Álvaro; Calvo, B.; Macı́as, Ramón; Lahoz, Fernando J.; Oro, Luis A.

doi:10.1021/om500374g

Cited by 7 publications

(2 citation statements)

References 51 publications

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“…These spectral patterns closely resemble that of previously reported rhodathiaborane pyridine-adducts, facilitating their identification through 11 B NMR spectroscopy. [42] Consistent with the 11 B NMR data, the 1 H-{ 11 B} NMR spectra of compound 2 exhibits five proton resonances between ( 11 B) + 4.03 and -0.14, confidently assignable to the boron-bound terminal hydrogen atoms. The expected 1:2:1:2:2 relative intensity pattern reveal further the presence of a plane of symmetry in the cluster.…”

Section: Synthesis and Characterization Of Eleven-vertex Neutral Dppb...supporting

confidence: 71%

Protonation of dppbz- and binap-ligated rhodathiaboranes yielding proton, hydride and hydrogen exchange

Vidondo,

Urdániz,

Sanz Miguel

et al. 2024

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The reaction of the eleven-vertex rhodathiaborane [8,8,8-(H)(PPh3)2-3-(NC5H5)-nido-7,8-RhSB9H10] (1) with 1,2-bis(dipheylphosphine)benzene (dppbz) and with (S)-(–)-2,2′-bis(diphenylphosphino)-1,1′-binaphyl (binap) affords [1,1-(2-dppbz)-3-(NC5H5)-closo-1,2-RhSB9H8] (2) and [1,1-(2-binap)-3-(NC5H5)-closo-1,2-RhSB9H8] (3), respectively. These eleven-vertex closo-rhodathiaborane chelates result from PPh3 ligand substitution at the rhodium centre and nido-to-closo structural cluster transformation driven by H2 loss. Treatment of compounds 2 and 3 with triflic acid (HTfO) leads to the formation of cationic clusters [(dppbz)(NC5H5)RhSB9H9]+ (4) and [(binap)(NC5H5)RhSB9H9]+ (5). In these clusters, the protons bind to the polyhedral clusters, acquiring hydride character and providing chemically non-rigidity that manifests through metal vertex-to-thiaborane pseudo-rotations and concomitant proton tautomerisms. The resulting cations react with hydrogen to form mixtures of protons, hydrogen and hydridorhodathiaboranes in equilibrium. These boron-based metal-hydride mixtures can be formulated as [(dppbz)(NC5H5)RhSB9H11]+ (6) and [(binap)(NC5H5)RhSB9H11]+ (8), resulting from the heterolytic cleavage of the H–H bond with the clusters’ full participation and the addition of hydrogen atoms to the cages. From the reaction mixture of 6 under H2, we have characterized the crystal structure of triflate-substituted [1,1-(dppbz)-3-(NC5H5)-closo-1,2-RhSB9H8] (7). In the reactions, there is conversion of electron and protons into hydrogen and of hydrogen into hydride ligands, demonstrating that these boron-based metal compounds act as electrons reservoirs, capable of promoting multielectron processes.

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Section: Synthesis and Characterization Of Eleven-vertex Neutral Dppb...supporting

confidence: 71%

Protonation of dppbz- and binap-ligated rhodathiaboranes yielding proton, hydride and hydrogen exchange

Vidondo,

Urdániz,

Sanz Miguel

et al. 2024

Preprint

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“…This contrasts with the bis-PR 3 -ligated analogues, [8,8,8-(H)(PR 3 ) 2 -9-(NC 5 H 5 )-nido-8,7-RhSB 9 H 10 ] + , where PR 3 = PPh 3 , PPh 3 and PMe 3 , or, PPh 3 and PMe 2 Ph, which are stable in the absence of free H 2 . 8,29 Insisting in the introductory paragraph, the possibility to modify the chemical and structural basis of this class of 11-vertex rhodathiaboranes is without doubt a driving force behind the study of the reaction chemistry of these polyhedral clusters. In this regard, the protonation of metallaheteroboranes to enhance their stereochemical non-rigidity and their Lewis acidity is a simple method that, in principle, could be of general application in polyhedral boron-containing compounds.…”

Section: Discussionmentioning

confidence: 99%

[1,1-(η²-dppe)-3-(NC₅H₅)-closo-1,2-RhSB₉H₈]: conformational lability and reactivity with H₂ upon protonation

et al. 2015

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Metallaheteroboranes are versatile compounds that can be conveniently modified and eventually tailored by ligand modification at either the metal centre or the boron vertices. Recently, we have discovered that protonation of some rhodathiaboranes affords cationic clusters with interesting reaction chemistry. In order to tune the reactivity of some of these polyhedral boron-based compounds, we have prepared air-stable orange [1,1-(η(2)-dppe)-3-(NC5H5)-closo-1,2-RhSB9H8] (2) by the treatment of the known hydridorhodathiaborane [8,8,8-(H)(PPh3)2-9-(NC5H5)-nido-8,7-RhSB9H9] (1) with dppe. The new 11-vertex rhodathiaborane, 2, reacts readily with triflic acid (TfOH) in CH2Cl2 to give orange cationic [8,8-(η(2)-dppe)-9-(NC5H5)-nido-8,7-RhSB9H9](+) (3). VT NMR experiments have allowed the characterization of a structural closo ↔ nido tautomerism, which involves hapticity changes in the ligation of the {SB9H9-(NC5H5)} moiety to the {Rh(dppe)} fragment, with the proton moving between the Rh(1)-B(3) and the B(9)-B(10) edges of the closo- and nido-isomers, respectively. The proton enhances the stereochemical non-rigidity and Lewis acidity of 3 versus the neutral 2. This modification of the chemical and structural basis permits the efficient heterolytic splitting of the H-H bond, leading to the formation of new hydridorhodathiaborane isomers [8,8,8-(H)(η(2)-dppe)-μ-8,9-(H)-9-(NC5H5)-nido-8,7-RhSB9H10](+) ()4 that are in equilibrium with the reactants, H2 and 3.

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Reversible Small‐Molecule Interactions with Coordinatively Unsaturated Metal Centers Held in Metallathiaborane Clusters

et al. 2017

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Hydridorhodathiaboranes: Synthesis, Characterization, and Reactivity

Cited by 7 publications

References 51 publications

Protonation of dppbz- and binap-ligated rhodathiaboranes yielding proton, hydride and hydrogen exchange

Protonation of dppbz- and binap-ligated rhodathiaboranes yielding proton, hydride and hydrogen exchange

[1,1-(η²-dppe)-3-(NC₅H₅)-closo-1,2-RhSB₉H₈]: conformational lability and reactivity with H₂ upon protonation

Reversible Small‐Molecule Interactions with Coordinatively Unsaturated Metal Centers Held in Metallathiaborane Clusters

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Hydridorhodathiaboranes: Synthesis, Characterization, and Reactivity

Cited by 7 publications

References 51 publications

Protonation of dppbz- and binap-ligated rhodathiaboranes yielding proton, hydride and hydrogen exchange

Protonation of dppbz- and binap-ligated rhodathiaboranes yielding proton, hydride and hydrogen exchange

[1,1-(η2-dppe)-3-(NC5H5)-closo-1,2-RhSB9H8]: conformational lability and reactivity with H2 upon protonation

Reversible Small‐Molecule Interactions with Coordinatively Unsaturated Metal Centers Held in Metallathiaborane Clusters

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[1,1-(η²-dppe)-3-(NC₅H₅)-closo-1,2-RhSB₉H₈]: conformational lability and reactivity with H₂ upon protonation