“To Bend or not To Bend?” Both! The Planar and Bent Structures of[(Ph3P)4Rh2(μ‐F)2]

Marshall, William J.; Aullón, Gabriel; Álvarez, Santiago; Dobbs, Kerwin D.; Grushin, Vladimir V.

doi:10.1002/ejic.200600523

Cited by 15 publications

(4 citation statements)

References 23 publications

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“…[38] As for the P1-Rh1-P2 bite angles, they measure 85.85(2)° for dppbz-ligated 2 and 90.91(5)° for binap-ligated 3. These values fall within in the range found for other crystallographically characterized dppbz-and binap-complexes such as [Rh(dppbz)2] + , [39] [RhCl(dppbz)(IPr)], [40] [Rh(binap)(NH3)2] + and [Rh(binap)(COD)]+. [38,41] This analysis reveals, therefore, that the chelates have different rhodium-to-cage conformations of the Rh(P-P) unit relative to the SB9 ligand, where P-P = dppbz or binap.…”

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

confidence: 84%

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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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: 84%

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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“…To confirm the monochelating property of PS-DPPBz, a cationic Rh(I) complex was employed as a metal source because it was prone to undergo bischelation by two bisphosphine ligands . In fact, the reaction of the soluble ligand DPPBz with [Rh(cod) 2 ]BF 4 (DPPBz/Rh 1:1) at rt afforded a mixture of mono-DPPBz-chelated complex [Rh(cod)(DPPBz)]BF 4 and bis-DPPBz-chelated complex [Rh(DPPBz) 2 ]BF 4 with NMR resonances at δ 58.0 and δ 62.9 (ppm), respectively (Figure a).…”

Section: Resultsmentioning

confidence: 99%

A Polystyrene-Cross-Linking Bisphosphine: Controlled Metal Monochelation and Ligand-Enabled First-Row Transition Metal Catalysis

et al. 2017

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A polystyrene-cross-linking bisphosphine PS-DPPBz was synthesized through radical emulsion copolymerization between 4-t-butylstyrene as a monomer and tetravinylated 1,2-bis(diphenylphosphino)benzene (DPPBz) as a 4-fold cross-linker. The location of the DPPBz bisphosphine moiety at the branching points of the cross-linked network organic polymer allowed controlled bisphosphine monochelation to transition metals under conditions where homogeneous ligands may form bischelated single metal complexes or multinuclear complexes. PS-DPPBz showed high ligand performance in firstrow transition metal catalysis, enabling challenging molecular transformations that were not possible through the screening of existing homogeneous ligands. In the Ni-catalyzed amination of aryl chlorides with N-alkyl-substituted primary amines, the substrate scope has been expanded to include 2,6-disubstituted aryl chlorides and N-tertiary-alkyl-substituted primary amines. PS-DPPBz was effective for the Ni-catalyzed C−H/C−O coupling between 1,3-azoles and monocyclic aryl pivalates, which showed poor reactivity in the reported homogeneous catalytic system based on 1,2-bis(dicyclohexylphosphino)ethane (DCYPE). The usefulness of the polymer-cross-linking strategy was also demonstrated in alkene hydroboration reactions catalyzed by Cu or Co.

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“…This small coupling could potentially occur via a through-bond or a through-space mechanism. For comparison, the trans - 2 J P,F coupling constants in borane-free rhodium(I) fluoride complexes such as [RhF(PPh 3 ) 3 ], [RhF(PPh 3 ) 2 (PPh 2 F)], and [Rh 2 (μ-F) 2 (PPh 3 ) 4 ] are 172, 217, and 196 Hz, respectively, and the cis - 2 J P,F coupling constants for [RhF(PPh 3 ) 3 ] and [RhF(PPh 3 ) 2 (PPh 2 F)] are 28.5 and 27 Hz, respectively …”

Section: Resultsmentioning

confidence: 99%

Diversity of Metal−Ligand Interactions in Halide (X = I, Br, Cl, F) and Halide-Free Ambiphilic Ligand Rhodium Complexes

Cowie¹,

Emslie²,

Jenkins

et al. 2010

Inorg. Chem.

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Reaction of the neutral ambiphilic ligand 2,7-di-tert-butyl-5-diphenylboryl-4-diphenylphosphino-9,9-dimethylthioxanthene (TXPB) with [{Rh(mu-Cl)(CO)(2)}(2)] yields [RhCl(CO)(TXPB)] (1) (Emslie et al. Organometallics 2006, 25, 5835). Complex 1 is square planar with the TXPB ligand bound to rhodium via the phosphine and thioether donors (these are features common to complexes 2-5, vide infra). Treatment of 1 with Me(3)SiBr and Me(3)SiI allowed for halide substitution to afford [RhBr(CO)(TXPB)] (2) and [RhI(CO)(TXPB)] (3), respectively. The halide co-ligands in complexes 1 and 2 form a strong bridging interaction between rhodium and the borane group in TXPB. The presence of stronger borane-halide coordination in 1 is clearly illustrated by an (11)B NMR chemical shift of 12 ppm versus 27 ppm in 2. In contrast, the iodide ligand in 3 forms only a weak bridging interaction to boron, leading to a B...I distance of 3.125(7) A, and an (11)B NMR chemical shift of 56 ppm (versus 69 ppm for free TXPB). A lower carbonyl stretching frequency in 3 (2002 cm(-1)) versus 1 or 2 (2008 and 2013 cm(-1), respectively) could be attributed to weakening of the Rh-X bond in 1 and 2 as a consequence of halide-borane coordination and/or a shorter Rh-S bond in complex 3. [Rh(CO)(TXPB-F)] (4) and the halide-free cation [Rh(CO)(TXPB)][PF(6)] (5) were accessed by reaction of 1 with [NMe(4)]F and Tl[PF(6)], respectively. Complex 4 is zwitterionic with fluoride bound to boron [(11)B NMR delta 4 ppm; B-F = 1.445(6) A; Rh...F = 3.261(3) A] and an eta(2)-interaction between the cationic rhodium center and the ipso- and ortho-carbon atoms of a B-phenyl ring in TXPB-F. By contrast, rhodium in 5 engages in an eta(2)-interaction with boron and the ipso-carbon of one B-phenyl ring; Rh-B and Rh-C(ipso) bond lengths in 5 are 2.557(3) and 2.362(2) A, respectively. The long Rh-B distance and an (11)B NMR chemical shift of 57 ppm are consistent with only a weak Rh-B interaction in 5, and a CO stretching frequency of 2028 cm(-1) (Nujol), versus 2004-2013 cm(-1) for complexes 1-4, is indicative of greatly reduced electron density in 5, relative to 1-4.

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“To Bend or not To Bend?” Both! The Planar and Bent Structures of[(Ph₃P)₄Rh₂(μ‐F)₂]

Cited by 15 publications

References 23 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

A Polystyrene-Cross-Linking Bisphosphine: Controlled Metal Monochelation and Ligand-Enabled First-Row Transition Metal Catalysis

Diversity of Metal−Ligand Interactions in Halide (X = I, Br, Cl, F) and Halide-Free Ambiphilic Ligand Rhodium Complexes

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