Synthesis and reactions of η-cycloheptatrienyl derivatives of molybdenum

Green, Malcolm L. H.; Ng, Dennis K. P.; Tovey, Robert; Chernega, Alexander N.

doi:10.1039/dt9930003203

Cited by 14 publications

(14 citation statements)

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“…(The corollary is that adventitious acid, perhaps from impure solvents, can initiate unwanted or unexpected electrontransfer-based reactions, as noted above for oxygen.) Thus, [Mo(η 5 -C 7 H 9 )(η-C 7 H 7 )] (E°′ ) -0.19 V) and HBF 4 ‚OEt 2 in diethyl ether 135 and [Co(PEt 3 ) 2 (η 5 -2,4dimethylpentadienyl)] and HBF 4 ‚OEt 2 or HO 3 SCF 3 in THF, 224…”

Section: [M(l-l) 3 ] 3+ (L-lmentioning

confidence: 99%

Chemical Redox Agents for Organometallic Chemistry

1996

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Section: [M(l-l) 3 ] 3+ (L-lmentioning

confidence: 99%

Chemical Redox Agents for Organometallic Chemistry

1996

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“…CpMoC 7 H 7 structure Mo-0 (C s symmetry) has a sandwich structure with one pentahapto η 5 -Cp ring and one heptahapto η 7 -C 7 H 7 ring, thereby giving the molybdenum atom the favored 18-electron configuration (Figure 7). This species has been synthesized by two methods, 25,26 and its methyl derivative (η 5 -C 5 H 4 Me)Mo(η 7 -C 7 H 7 ) is structurally characterized by X-ray crystallography. 26 The experimental average Mo−C distances to the η 5 -C 5 H 5 and η 7 -C 7 H 7 rings of 2.31 and 2.25 Å in (η 5 -C 5 H 4 Me)Mo(η 7 -C 7 H 7 ) are close to those of 2.33 and 2.28 Å, respectively, predicted for Mo-0.…”

Section: Resultsmentioning

confidence: 99%

“…This species has been synthesized by two methods, 25,26 and its methyl derivative (η 5 -C 5 H 4 Me)Mo(η 7 -C 7 H 7 ) is structurally characterized by X-ray crystallography. 26 The experimental average Mo−C distances to the η 5 -C 5 H 5 and η 7 -C 7 H 7 rings of 2.31 and 2.25 Å in (η 5 -C 5 H 4 Me)Mo(η 7 -C 7 H 7 ) are close to those of 2.33 and 2.28 Å, respectively, predicted for Mo-0.…”

Section: Resultsmentioning

confidence: 99%

“…Subsequently, the red (η 3 -C 7 H 7 )Co(CO) 3 , also with a trihapto η 3 -C 7 H 7 ring, was also synthesized with a structure closely related to that of (η 4 -C 8 H 8 )Fe(CO) 3 . The carbonyl-free sandwich compound CpMo(η 7 -C 7 H 7 ) with a heptahapto η 7 -C 7 H 7 ring was initially prepared in low yield by the reaction of MoCl 5 with a mixture of CpMgBr, iPrMgBr, and cycloheptatriene and later in much better yield by the reaction of (η 7 -C 7 H 7 )Mo(NCMe)I 2 with sodium cyclopentadienide . The corresponding methylcyclopentadienyl derivative (η 5 -C 5 H 4 Me)Mo(η 7 -C 7 H 7 ) has been structurally characterized by X-ray diffraction …”

Section: Introductionmentioning

confidence: 99%

“…26 The corresponding methylcyclopentadienyl derivative (η 5 -C 5 H 4 Me)Mo(η 7 -C 7 H 7 ) has been structurally characterized by X-ray diffraction. 26 Another early observation involving seven-and eightmembered ring cyclopolyolefins is relevant to the results discussed in this paper. The simple thermal reaction of CpV(CO) 4 with boiling cycloheptatriene was reported in 1959 to result in the loss of all four carbonyl groups to give the sandwich compound CpV(η 7 -C 7 H 7 ).…”

Section: Introductionmentioning

confidence: 99%

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Energetics of Variable Hapticity of Carbocyclic Rings in Cyclopentadienylmetal Carbonyl Systems of the Second Row Transition Metals C₅H₅M(CO)_nC_mH_m (M = Ru, Tc, Mo, Nb) Including Mechanistic Studies of Carbonyl Dissociation

et al. 2018

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Decarbonylation of the experimentally known CpRu(CO)2(η1-C5H5), CpMo(CO)2(η3-C7H7), and CpNb(CO)2(η4-C8H8) (Cp = η5-C5H5), each with uncomplexed 1,3-butadiene units in the C n H n ring, as well as the related CpTc(CO)2(η2-C6H6), to give the corresponding carbonyl-free derivatives CpM(η n -C n H n ) derivatives has been studied by density functional theory. For ruthenium, technetium, and molybdenum the coordinated C n H n ring of the intermediate monocarbonyl CpM(CO)(η n–2-C n H n ) contains an uncomplexed CC double bond and each decarbonylation step proceeds with a significant energy barrier represented by a higher energy transition state. However, decarbonylation of CpNb(CO)2(η4-C8H8) to the monocarbonyl proceeds without an energy barrier, preserving the tetrahapto coordination of the C8H8 ring to give CpNb(CO)(η4-C8H8) in which the niobium atom has only a 16-electron configuration. All of the monocarbonyl derivatives CpM(CO)(C n H n ) are predicted to be strongly energetically disfavored with respect to disproportionation to give CpM(CO)2(C n H n ) + CpM(C n H n ). This allows us to understand the failure to date to synthesize any of the monocarbonyl derivatives.

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Chelate Complexes of Functionalized Cycloheptatrienyl Ligands: 17- and 18-Electron Molybdenum Complexes with Linked Cycloheptatrienyl−Phosphane Ligands and Their Use in Transition Metal Catalysis

Tamm

Baum

Lügger

et al. 2002

Eur. J. Inorg. Chem.

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The synthesis of P-functionalized molybdenum chelate complexes incorporating the linked cycloheptatrienyl− phosphane ligand [2-(diphenylphosphanyl)phenyl]cycloheptatrienyl, o-Ph 2 P−C 6 H 4 −C 7 H 6 , is described. The air-stable ligand precursor [2-(cyclohepta-2,4,6-trienyl)phenyl]diphenylphosphane (2) can be obtained in large quantities by addition of lithiated 2-BrC 6 H 4 PPh 2 (1) to the tropylium cation C 7 H 7 + . Hydride abstraction employing the trityl cation, Ph 3 C + , results in the formation of the tricyclic phosphonium salt 3. The P-functionalized cycloheptatriene 2 acts as an eight-electron ligand on reaction with Mo(CO) 6 to afford the cycloheptatriene−phosphane complex [(o-Ph 2 PC 6 H 4 -η 6 -C 7 H 7 )Mo(CO) 2 (P−Mo)] (4) as a single, chiral regioisomer, which undergoes clean hydride abstraction on treatment

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Synthesis and reactions of η-cycloheptatrienyl derivatives of molybdenum

Cited by 14 publications

References 35 publications

Chemical Redox Agents for Organometallic Chemistry

Chemical Redox Agents for Organometallic Chemistry

Energetics of Variable Hapticity of Carbocyclic Rings in Cyclopentadienylmetal Carbonyl Systems of the Second Row Transition Metals C₅H₅M(CO)_nC_mH_m (M = Ru, Tc, Mo, Nb) Including Mechanistic Studies of Carbonyl Dissociation

Chelate Complexes of Functionalized Cycloheptatrienyl Ligands: 17- and 18-Electron Molybdenum Complexes with Linked Cycloheptatrienyl−Phosphane Ligands and Their Use in Transition Metal Catalysis

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Synthesis and reactions of η-cycloheptatrienyl derivatives of molybdenum

Cited by 14 publications

References 35 publications

Chemical Redox Agents for Organometallic Chemistry

Chemical Redox Agents for Organometallic Chemistry

Energetics of Variable Hapticity of Carbocyclic Rings in Cyclopentadienylmetal Carbonyl Systems of the Second Row Transition Metals C5H5M(CO)nCmHm (M = Ru, Tc, Mo, Nb) Including Mechanistic Studies of Carbonyl Dissociation

Chelate Complexes of Functionalized Cycloheptatrienyl Ligands: 17- and 18-Electron Molybdenum Complexes with Linked Cycloheptatrienyl−Phosphane Ligands and Their Use in Transition Metal Catalysis

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Energetics of Variable Hapticity of Carbocyclic Rings in Cyclopentadienylmetal Carbonyl Systems of the Second Row Transition Metals C₅H₅M(CO)_nC_mH_m (M = Ru, Tc, Mo, Nb) Including Mechanistic Studies of Carbonyl Dissociation