Synthesis and Reactivity of Fluoro Complexes:  Part 2.1Rhodium(I) Fluoro Complexes with Alkene and Phosphine Ligands. Synthesis of the First Isolated Rhodium(I) Bifluoride Complexes. Structure of [Rh3(μ3-OH)2(COD)3](HF2) by X-ray Powder Diffraction

Vicente, José; Gil‐Rubio, Juan; Bautista, Delia; Sironi, Angelo; Masciocchi, Norberto

doi:10.1021/ic049585e

Cited by 44 publications

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“…The cluster reacts with excess PPh 3 to give a mixture of RhF(PPh 3 ) 3 and Rh 2 (m-OH) 2 (PPh 3 ) 4 (4:1), whereas the same reaction with PPr i 3 gives RhF(PPr i 3 )(COD), suggesting that Rh(I) has a greater affinity for fluoride when phosphine-coordinated rather than COD-ligated, as evidenced by the reaction of Rh 2 (m-OH) 2 (PR 3 ) 4 (R = Ph, Pr i ) with Et 3 N Á 3HF to give Rh 2 (m-F) 2 (PR 3 ) 4 53. Reaction of Rh 2 (m-OH) 2 (Z 2 :Z 2 -COD) 2 with 73% HF has also been shown to produce the same trinuclear dihydroxy cluster, rather than the fluoride complex {RhF(COD)} n as previously reported, although rhodium fluoride complexes Rh 2 (m-F) 2 (COE) 4 can be prepared from Rh 2 (m-OH) 2 (Z 2 -COE) 2 and Et 3 N Á 3HF 54. [Rh 2 (m-PNNP)(CO) 4 ] + [PNNP = 3,5-bis{(diphenylphosphino)methyl}pyrazolato] reacts with terminal alkynes RCRCH (R = p-Tol, Bu) or with the dinuclear alkynyl complex Rh 2 (m-Z 1 :Z 2 -CRCR)(m-PNNP)(CO) 2 (R = H, SiMe 3 ) to give the tetranuclear cluster 34, containing a bent chain of rhodium atoms with the a-carbon of the alkynyl unit bound to all four metal atoms, and the CRC unit pbound to one of the ''wing-tip'' rhodiums.…”

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confidence: 62%

Organo‐Transition‐Metal Cluster Complexes

Humphrey

Cifuentes

2004

ChemInform

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This chapter covers the chemistry of metal carbonyl and organometallic clusters containing three or more metal atoms. The treatment is in Periodic Group order, homometallic compounds being followed by heterometallic clusters. Ligands are not shown for high-nuclearity clusters, emphasis being placed on core geometry. 2 Spectroscopic studies The first gas-phase infrared spectra of a range of anionic iron clusters ([Fe 3 (CO) 10 ] À to [Fe 5 (CO) 14 ] À) have been reported. Spectral data of this type were combined with DFT calculations for smaller complexes ([Fe(CO) 4 ] À , [Fe 2 (CO) 7 ] À , [Fe 2 (CO) 8 ] À) to obtain structural information for the cluster anions. 1 Spectroelectrochemical and computational studies on the reversible two-electron reduction of bis(alkynyl) clusters Ru 4 (m 4-Z 2-RC 2 R) 2 (m-CO)(CO) 10 show the first-formed product, which contains a square-planar metal core with the alkyne ligands coordinated to opposite faces, quickly isomerizes to a thermodynamically more stable product where the alkyne ligands lie parallel to each other across the metal framework. 2 Quantitative IR analysis of Rh 4 (m-CO) 3 (CO) 9 , combined with deconvolution techniques, has been used to obtain a spectrum of the all-terminal CO complex Rh 4 (CO) 12 , even though it constitutes only ca. 1% of the sample. 3 Laser desorption time-of-flight mass spectrometry affords the best results for anionic clusters when they are examined in the absence of matrix, the parent ion being observed in the majority of cases. In contrast, the spectra of neutral clusters show high-mass cluster aggregation and decarbonylation, with the CO:M ratio dropping with increasing cluster size, suggesting a metal-core rearrangement. 4 A picosecond time-resolved UV/Vis and IR spectroscopic study of the photolysis of Os 3 (CO) 10 (s-cis-cyclohexa-1,3-diene), combined with DFT calculations on the geometry-optimized Os 3 (CO) 10 (buta-1,3-diene), indicates products result from stepwise formation of two bridging carbonyl ligands, with each intermediate containing a cleaved Os-Os bond bridged by the 1,3-diene ligand. 5 Similar comparisons of the photochemical reactivity of the diimine clusters Os 3 (CO) 10 (Z-L) (L = [AcPy-MV] 2+ , Pr i-AcPy, 1) show that irradiation of the methyl viologen cluster results in transfer of a cluster-core electron to the lowest p * orbital of the MV 2+ unit, resulting in formation of a charge-separated state that is stable in acetonitrile, but either decays to regenerate the starting cluster (88%) or forms stable open-core biradicals (12%) in acetone. Electrochemical reduction of the viologen cluster decreases the electron-accepting characteristics of the ligand such that irradiation results in formation of zwitterions analogous to those observed from the irradiation of related non-substituted Os 3 (CO) 10 (a-diimine) clusters. 6 The related mixed-metal cluster RuOs 2 (CO) 10 (Pr i-AcPy) contains the diimine ligand coordinated to the ruthenium atom and also produces biradical products on irradiation in weakly coordinating so...

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confidence: 62%

Organo‐Transition‐Metal Cluster Complexes

Humphrey

Cifuentes

2004

ChemInform

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“…31 The Rh−F bond length (2.0107(12) Å) is closer to the value for Rh(COD)(PPh 3 )F (2.0214(12) Å) than that in Rh(COD)-(PPh 3 )(FHF) (2.083(2) Å). 32 The short Rh−F bond probably reflects very weak RhF···HF hydrogen bonding. The Rh−F···F angle and F(1)···F(6) distance in 7 are similar to those reported for trans-[Rh(Ph 3 P) 2 (Ph 2 PF)(FHF)].…”

Section: ■ Resultsmentioning

confidence: 99%

Activation of B–H, Si–H, and C–F Bonds with Tp′Rh(PMe₃) Complexes: Kinetics, Mechanism, and Selectivity

et al. 2015

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The photochemical reactions of Tp'Rh(PMe3)H2 (1) and thermal reactions of Tp'Rh(PMe3)(CH3)H (1a, Tp' = tris(3,5-dimethylpyrazolyl)borate) with substrates containing B-H, Si-H, C-F, and C-H bonds are reported. Complexes 1 and 1a are known activators of C-H bonds, including those of alkanes. Kinetic studies of reactions with HBpin and PhSiH3 show that photodissociation of H2 from 1 occurs prior to substrate attack, whereas thermal reaction of 1a proceeds by bimolecular reaction with the substrate. Complete intramolecular selectivity for B-H over C-H activation of HBpin (pin = pinacolate) leading to Tp'Rh(PMe3)(Bpin)H is observed. Similarly, the reaction with Et2SiH2 shows a strong preference for Si-H over C-H activation, generating Tp'Rh(PMe3)(SiEt2H)H. The Rh(Bpin)H and Rh(SiEt2H)H products were stable to heating in benzene in accord with DFT calculations that showed that reaction with benzene is endoergic. The intramolecular competition with PhSiH3 yields a ∼1:4 mixture of Tp'Rh(PMe3)(C6H4SiH3)H and Tp'Rh(PMe3)(SiPhH2)H, respectively. Reaction with pentafluoropyridine generates Tp'Rh(PMe3)(C5NF4)F, while reaction with 2,3,5,6-tetrafluoropyridine yields a mixture of C-H and C-F activated products. Hexafluorobenzene proves unreactive. Crystal structures are reported for B-H, Si-H, and C-F activated products, but in the latter case a bifluoride complex Tp'Rh(PMe3)(C5NF4)(FHF) was crystallized. Intermolecular competition reactions were studied by photoreaction of 1 in C6F6 with benzene and another substrate (HBpin, PhSiH3, or pentafluoropyridine) employing in situ laser photolysis in the NMR probe, resulting in a wide-ranging map of kinetic selectivities. The mechanisms of intramolecular and intermolecular selection are analyzed.

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“…In summary, we have developed a new type of catalytic asymmetric reaction producing axially chiral fluorinated allenes with high % ee , where the enantioposition‐selective β‐F elimination from an alkenyl‐Rh intermediate [24] is a key step in the catalytic cycle.…”

Section: Methodsmentioning

confidence: 99%

Asymmetric Synthesis of Fluorinated Allenes by Rhodium‐Catalyzed Enantioselective Alkylation/Defluorination of Propargyl Difluorides with Alkylzincs

Hayashi

2021

Angewandte Chemie

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The reaction of propargyl difluorides R1CF2C≡CR2 with alkylzincs R3ZnCl giving axially chiral fluorinated allenes R1FC=C=CR2R3 with high enantioselectivity (up to 99 % ee) was found to be catalyzed by a chiral diene/rhodium complex. A key step in the catalytic cycle is selective elimination of one of the enantiotopic fluorides at the β‐position of an alkenyl‐Rh intermediate, which is generated by regioselective addition of R3‐Rh onto the triple bond of the starting difluorides.

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Synthesis and Reactivity of Fluoro Complexes: Part 2.¹Rhodium(I) Fluoro Complexes with Alkene and Phosphine Ligands. Synthesis of the First Isolated Rhodium(I) Bifluoride Complexes. Structure of [Rh₃(μ₃-OH)₂(COD)₃](HF₂) by X-ray Powder Diffraction

Cited by 44 publications

References 44 publications

Organo‐Transition‐Metal Cluster Complexes

Organo‐Transition‐Metal Cluster Complexes

Activation of B–H, Si–H, and C–F Bonds with Tp′Rh(PMe₃) Complexes: Kinetics, Mechanism, and Selectivity

Asymmetric Synthesis of Fluorinated Allenes by Rhodium‐Catalyzed Enantioselective Alkylation/Defluorination of Propargyl Difluorides with Alkylzincs

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Synthesis and Reactivity of Fluoro Complexes: Part 2.1Rhodium(I) Fluoro Complexes with Alkene and Phosphine Ligands. Synthesis of the First Isolated Rhodium(I) Bifluoride Complexes. Structure of [Rh3(μ3-OH)2(COD)3](HF2) by X-ray Powder Diffraction

Cited by 44 publications

References 44 publications

Organo‐Transition‐Metal Cluster Complexes

Organo‐Transition‐Metal Cluster Complexes

Activation of B–H, Si–H, and C–F Bonds with Tp′Rh(PMe3) Complexes: Kinetics, Mechanism, and Selectivity

Asymmetric Synthesis of Fluorinated Allenes by Rhodium‐Catalyzed Enantioselective Alkylation/Defluorination of Propargyl Difluorides with Alkylzincs

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Synthesis and Reactivity of Fluoro Complexes: Part 2.¹Rhodium(I) Fluoro Complexes with Alkene and Phosphine Ligands. Synthesis of the First Isolated Rhodium(I) Bifluoride Complexes. Structure of [Rh₃(μ₃-OH)₂(COD)₃](HF₂) by X-ray Powder Diffraction

Activation of B–H, Si–H, and C–F Bonds with Tp′Rh(PMe₃) Complexes: Kinetics, Mechanism, and Selectivity