Synthesis and X-ray crystal structure of a tri-iridium cluster, [Ir3(CO)6(Ph)(µ3-PPh)(µ-dppm)]

Harding, Margaret M.; Nicholls, Barry S.; Smith, Anthony K.

doi:10.1039/dt9830001479

Cited by 23 publications

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“…h i b i t e d .The Ir(1)ÀC distances to the σ-phenyl ligands are Ir(2)À C(33) = 2.127(11) Å and Ir(3)ÀC(39) = 2.130(10) Å. These distances are similar to the IrÀC distances to the phenyl ligands in the Ir 3 , Ir 4 , and Ir 8 complexes Ir 3 (CO) 9 (Ph)-(μ 3 -PPh)(μ-dppm) (2.084(16) Å),27 Ir 4 (CO) 8 (η 1 -Ph)[μ 4 -η 3 -PhPC(H)CPh]((μ-PPh 2 ) (2.09(1) Å),28 and Ir 8 (CO) 16 (η 1 -Ph)-(μ-PPh 2 )(μ 4 -PPh) (2.06(4) Å) 29. An ORTEP diagram of the molecular structure of 4 is shown in Figure2.…”

supporting

confidence: 56%

α-Cleavage of Phenyl Groups from GePh₃Ligands in Iridium Carbonyl Cluster Complexes. A Mechanism and Its Role in the Synthesis of Bridging Germylene Ligands

et al. 2011

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At 110 °C, the compound HIr(CO) 3 (GePh 3 ) 2 (1) was decarbonylated and transformed into five polynuclear iridium compounds, Ir 2 (CO) 6 (μ-GePh 2 )(GePh 3 ) 2 (2), Ir 3 -(CO) 6 (η 1 -Ph) 2 (μ-GePh 2 ) 3 (GePh 3 ) (3), Ir 3 (CO) 6 (η 1 -Ph)(μ-GePh 2 ) 3 (GePh 3 ) 2 (4), Ir 3 (CO) 6 (μ-CO)(μ-GePh 2 ) 2 (GePh 3 ) 3 (5), and Ir 6), by a combination of condensation and phenylcleavage processes. The triiridium compounds 3À6 are all new and have been characterized by single-crystal X-ray diffraction analyses. Each new compound consists of a closed triangular cluster of three iridium atoms with two or three diphenylgermylene ligands bridging the IrÀIr bonds. Separately, compound 5 was converted to 4 in 68% yield by decarbonylation and cleavage of a phenyl group from one of its GePh 3 ligands by heating a toluene solution to reflux (110 °C) for 1 h. A computational study has revealed that the mechanism of transformation of 5 to 4 occurs by elimination of the bridging carbonyl ligand followed by a "deinsertion" α-cleavage of a phenyl group from one of the GePh 3 ligands.

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confidence: 56%

α-Cleavage of Phenyl Groups from GePh₃Ligands in Iridium Carbonyl Cluster Complexes. A Mechanism and Its Role in the Synthesis of Bridging Germylene Ligands

et al. 2011

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“…mentioned above 6a are the first examples of symmetrical bridging phenyl groups across Ru−Ru bonds. Other platinum group clusters with η 1 -phenyl groups are also known . As for a σ,π-interaction of a vinyl ligand, the ampy bridged cluster of Cabeza has been shown to add diphenylacetylene in such a way that the resulting alkenyl ligand employs a σ,π -interaction in bridging a Ru−Ru bond, similar to the situation for 5 .…”

Section: Resultsmentioning

confidence: 94%

Reactions of the Trinuclear Cluster (μ₂-H)Ru₃(CO)₉(μ₃,η²-SCNHPhNPh): Synthesis and Molecular Structure of Ru₃(CO)₆(PPh₃)(μ₂,η²-C₆H₅)- (μ₂-PPh₂)(μ₃-S), a Complex Containing a Phenyl Ligand with a Rare σ,π-Coordination Mode

et al. 1996

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Reactions of the previously isolated trinuclear cluster (μ2-H)Ru3(CO)9(μ3,η2-SCNHPhNPh) (1) with excess diphenylthiourea result in cluster fragmentation to produce the mononuclear complex Ru(CO)2(η2-SCNHPhNPh)2 (2) containing two bidentate diphenylthioureato ligands. Room-temperature reactions of 1 with 1 or 2 equiv of triphenylphosphine result in substitution of one or two carbonyl groups, respectively, to give the clusters (μ2-H)Ru3(CO)8(PPh3)(μ3,η2-SCNHPhNPh) (3) and (μ2-H)Ru3(CO)7(PPh3)2(μ3,η2-SCNHPhNPh) (4). An X-ray crystal structure analysis shows 3 to represent a monosubstituted derivative of 1 with the PPh3 ligand occupying an equatorial position on one of the two bridgehead ruthenium atoms; the crystal belongs to the triclinic space group P1̄; Z = 2, a = 10.014(2) Å, b = 14.449(4) Å, c = 14.573(4) Å, α = 100.38(2)°, β = 98.70(2)°, and γ = 107.20(2)°. Thermolysis of either 1 in the presence of 2 equiv of PPh3, or of 4 alone, gives the sulfur-capped, trinuclear cluster Ru3(CO)7(PPh3)(μ2,η2-C6H5)(μ2-PPh2)(μ3-S) (5). X-ray structural analysis of 5 shows a diphenylphosphido bridge and a phenyl bridge resulting from P−C bond activation of a PPh3 group and C−H activation of the aryl group; crystals of 5 are monoclinic, space group P21/n; Z = 4, a = 10.824(1) Å, b = 19.193(5) Å, c = 20.953(2) Å, and β = 97.44(1)°. Diphenylphosphinoethane (dppe) is found to replace two carbonyl ligands on two adjacent Ru atoms to give the cluster (μ2-H)Ru3(CO)7(Ph2PCH2CH2PPh2)- (μ3,η2-SCNHPhNPh) (6) whose X-ray structural analysis shows a dppe ligand bound cis to the μ2-S of the diphenylthioureato ligand and cis to the μ2-H ligand. Crystals of 6 are monoclinic, space group P21/n; Z = 4, a = 17.667(7) Å, b = 17.681(5) Å, c = 18.049(4) Å, and β = 108.06(2)°.

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“…The arrangement of Ir(2)−P(3) = 2.285(4) Å and Ir(4)−P(3) = 2.303(4) Å, so either the gold atoms changed sites, which is likely given the known fluxionality of these atoms, or the phosphorus atom changed sites, which seems less likely since tertiary phosphines 11 Ph], 10 2.125(13) Å; [ E t 4 N ] [ I r 4 ( C O ) 1 1 ( P P h 2 C 6 H 4 ) ] , 1 0 2 . 0 9 6 ( 1 2 ) Å ; Ir 5 (CO) 11 (PPh 3 )(PPh 2 C 6 H 4 ), 10 2.14(2) Å; Ir 3 (CO) 9 (Ph)(μ 3 -PPh)(μ-dppm), 2.084(16) Å, 26 and Ir 4 (CO) 8 (η 1 -Ph)[μ 4 -η 3 -PhPC(H)CPh](μ-PPh 2 ), 2.09(1) Å. 27 There are no hydride ligands in 5, so it is assumed that the hydrogen atom that was cleaved from the phenyl ring in the ortho-metalation process was combined with the phenyl group that was also cleaved from the phosphorus atom, and the two were subsequently eliminated from the complex in the form of benzene.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Iridium–Gold Cluster Compounds: Syntheses, Structures, and an Unusual Ligand-Induced Skeletal Rearrangement

2012

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The new iridium−gold complex Ir 4 (CO) 11 (Ph)(μ-AuPPh 3 ), 1 was obtained from the reaction of the tetrairidium anion [Ir 4 (CO) 11 (Ph)] − with [Au(PPh 3 )] [NO 3 ]. Two new iridium−gold complexes Ir 4 (CO) 10 (AuPPh 3 ) 2 , 2, and Ir 4 (CO) 11 (AuPPh 3 ) 2 , 3, were obtained from the reaction of [HIr 4 (CO) 11 ] − with [Au(PPh 3 )][NO 3 ]. Compounds 1−3 were structurally characterized by single crystal X-ray diffraction analyses. Compound 2 adds CO reversibly to form compound 3. In this process, the octahedral Ir 4 Au 2 cluster of 2 is converted into the Au(PPh 3 )-capped Ir 4 Au trigonal bipyramidal cluster found in 3. Compounds 2 and 3 have been investigated by DFT computational analyses in order to understand the metal−metal bonding and the mechanism of their interconversion by CO addition and elimination. Compound 2 adds PPh 3 to form the compound Ir 4 (CO) 10 (PPh 3 )-(AuPPh 3 ) 2 , 4, which is structurally similar to 3. Compound 4 loses CO and benzene when heated to form the compound Ir 4 (CO) 9 (μ 3 -PPhC 6 H 4 )(AuPPh 3 ) 2 , 5, which contains a triply bridging PPhC 6 H 4 ligand. ■ INTRODUCTIONApplications for iridium in catalysis continue to grow. 1 Although most catalytic applications are of a homogeneous type, 2 it has been shown that iridium clusters can serve as precursors to heterogeneous nanoscale catalysts that exhibit good activity for the hydrogenation of aromatics and olefins. 3 Years ago, Sinfelt showed that the addition of iridium to platinum greatly improved its activity for the catalytic reforming of petroleum. 4 Heterogeneous iridium−iron catalysts derived from bimetallic cluster complexes have been shown to exhibit exceptional catalytic activity for the formation of methanol from synthesis gas. 5 Recently, gold nanoparticles have been shown to exhibit significant catalytic activity for the oxidation of CO and certain olefins. 6 Combining transition metals with gold has led to interesting new bimetallic catalysts for the oxidation of hydrocarbons. 7 There have been very few reports of iridium−gold carbonyl cluster complexes, 8,9 and their catalytic activity has not yet been investigated.We have recently reported the synthesis and structural characterization of the tetrairidium anion, [Ir 4 (CO) 11 (Ph)] − . 10 [Ir 4 (CO) 11 (Ph)] − has been shown to react with Ir(CO)-(PPh 3 ) 2 Cl to form the pentairidium complex Ir 5 (CO) 12 Ph-(PPh 3 ) by halide displacement combined with the elimination of one PPh 3 ligand, Scheme 1. 10 It also reacts with [(COD)-Ir(Cl)] 2 to form a series of higher nuclearity iridium carbonyl cluster complexes containing COD and COD transformed ligands, Scheme 2. 11 We have now investigated the reaction of [Ir 4 (CO) 11 (Ph)] − with [Au(PPh 3 )][NO 3 ] and have obtained the gold− tetrairidium cluster complex Ir 4 (CO) 11 (Ph)(μ-AuPPh 3 ), 1. For comparisons, we have investigated the reaction of [HIr 4 -(CO) 11 ] − with [Au(PPh 3 )][NO 3 ] and have obtained two new iridium−gold carbonyl cluster complexes Ir 4 (CO) 10 (AuPPh 3 ) 2 , 2, and Ir 4 (CO) 11 (AuPPh 3 ) 2 ...

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Synthesis and X-ray crystal structure of a tri-iridium cluster, [Ir₃(CO)₆(Ph)(µ₃-PPh)(µ-dppm)]

Cited by 23 publications

References 0 publications

α-Cleavage of Phenyl Groups from GePh₃Ligands in Iridium Carbonyl Cluster Complexes. A Mechanism and Its Role in the Synthesis of Bridging Germylene Ligands

α-Cleavage of Phenyl Groups from GePh₃Ligands in Iridium Carbonyl Cluster Complexes. A Mechanism and Its Role in the Synthesis of Bridging Germylene Ligands

Reactions of the Trinuclear Cluster (μ₂-H)Ru₃(CO)₉(μ₃,η²-SCNHPhNPh): Synthesis and Molecular Structure of Ru₃(CO)₆(PPh₃)(μ₂,η²-C₆H₅)- (μ₂-PPh₂)(μ₃-S), a Complex Containing a Phenyl Ligand with a Rare σ,π-Coordination Mode

Iridium–Gold Cluster Compounds: Syntheses, Structures, and an Unusual Ligand-Induced Skeletal Rearrangement

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Synthesis and X-ray crystal structure of a tri-iridium cluster, [Ir3(CO)6(Ph)(µ3-PPh)(µ-dppm)]

Cited by 23 publications

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α-Cleavage of Phenyl Groups from GePh3Ligands in Iridium Carbonyl Cluster Complexes. A Mechanism and Its Role in the Synthesis of Bridging Germylene Ligands

α-Cleavage of Phenyl Groups from GePh3Ligands in Iridium Carbonyl Cluster Complexes. A Mechanism and Its Role in the Synthesis of Bridging Germylene Ligands

Reactions of the Trinuclear Cluster (μ2-H)Ru3(CO)9(μ3,η2-SCNHPhNPh): Synthesis and Molecular Structure of Ru3(CO)6(PPh3)(μ2,η2-C6H5)- (μ2-PPh2)(μ3-S), a Complex Containing a Phenyl Ligand with a Rare σ,π-Coordination Mode

Iridium–Gold Cluster Compounds: Syntheses, Structures, and an Unusual Ligand-Induced Skeletal Rearrangement

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Synthesis and X-ray crystal structure of a tri-iridium cluster, [Ir₃(CO)₆(Ph)(µ₃-PPh)(µ-dppm)]

α-Cleavage of Phenyl Groups from GePh₃Ligands in Iridium Carbonyl Cluster Complexes. A Mechanism and Its Role in the Synthesis of Bridging Germylene Ligands

α-Cleavage of Phenyl Groups from GePh₃Ligands in Iridium Carbonyl Cluster Complexes. A Mechanism and Its Role in the Synthesis of Bridging Germylene Ligands

Reactions of the Trinuclear Cluster (μ₂-H)Ru₃(CO)₉(μ₃,η²-SCNHPhNPh): Synthesis and Molecular Structure of Ru₃(CO)₆(PPh₃)(μ₂,η²-C₆H₅)- (μ₂-PPh₂)(μ₃-S), a Complex Containing a Phenyl Ligand with a Rare σ,π-Coordination Mode