Pentabenzylcyclopentadienyl molybdenum and tungsten hydrides: Syntheses, structures and electrochemistry of [MHCpBz(CO)2(L)] (L=CO, PMe3, PPh3)

Antunes, Maria Augusta; Namorado, Sónia; Azevedo, Cristina G. de; Lemos, M.A.N.D.A.; Duarte, M. Teresa; Ascenso, José R.; Martins, Ana M.

doi:10.1016/j.jorganchem.2010.02.012

Cited by 12 publications

(1 citation statement)

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“…There is still much to learn about the mechanisms of reactions of odd-electron transition metal hydride complexes. Such species are often generated by the oxidation or reduction of stable even-electron complexes. − Hu, Norton, and co-workers and Poli have reviewed cases where the oxidation of a diamagnetic hydride MHL n to a paramagnetic hydride cation [MHL n ] + decreases the p K a for proton loss from the metal significantly, often by greater than 20 p K a units (Scheme ). This was first discovered by Ryan, Tilset, and Parker when they measured the electrochemical potentials E 1 and E 2 and then used known p K a 1 values in a thermochemical cycle to obtain p K a 2 .…”

Section: Introductionmentioning

confidence: 99%

Systematic Trends in the Electrochemical Properties of Transition Metal Hydride Complexes Discovered by Using the Ligand Acidity Constant Equation

2020

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Understanding the thermodynamics of paramagnetic transition metal hydride complexes, especially of the abundant 3d metals, is important in the design of electrocatalysts and organometallic catalysts. The pK a MeCN([MHLn]+/[MLn) of paramagnetic hydrides in MeCN are estimated for the first time using the ligand acidity constant (LAC) equation where contributions to the pK a MeCN from each ligand are simply added together, with the sum corrected for effects of charge and 5d metals. The pK a LAC–MeCN([MHLn]+/MLn) of over 200 hydride complexes MHLn are used, along with their electrochemical potentials from the literature, in an uncommonly applied thermochemical cycle in order to reveal systematic trends in the redox couples MIII/II and MV/IV (M = Cr, Mo, W), MnII/I, ReVI/V and ReIV/III, MIII/II and MIV/III (M = Fe, Ru, Os), and MIII/II and MII/I (M = Co, Rh, and Ir) and allow the estimation of the bond dissociation free energies BDFE(MH) of the unoxidized hydrides MHLn and the prediction of the electrochemical potential for their oxidation. Density functional theory (DFT) calculations are used to validate the pK a LAC–MeCN values of hydrides of WIII, MnII, FeIII, RuIII, CoII, and NiIII. When a pK a LAC–MeCN is less than zero for a given complex [MHLn]+, the oxidation of MHLn is irreversible due to proton loss from the oxidized complex to the solvent. When pK a LAC–MeCN ≫ 0, the oxidation is reversible when there is no gross change in the coordination geometry upon a change in the redox state. Twenty paramagnetic hydrides prepared in bulk all have pK a LAC–MeCN > 8.

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Section: Introductionmentioning

confidence: 99%

Systematic Trends in the Electrochemical Properties of Transition Metal Hydride Complexes Discovered by Using the Ligand Acidity Constant Equation

2020

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Unusual Thermal Reactivity of [W(CPh)(NCMe)(η²‐C₆₀)(η⁵‐C₅Ph₅)] in Chlorobenzene Involving Activation of All Ligands

Yeh

2011

Angewandte Chemie

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Rummel um Wolfram: Das Erhitzen von 1 in Chlorbenzol liefert 2, 3, C6Ph6 und C60. Bei diesem Prozess werden C‐H‐Bindungen der Liganden aktiviert und neu gebildet, und Chloratome des Lösungsmittels werden abgespalten. C6Ph6 resultiert vermutlich aus dem Einschub des Benzylidinliganden in den C5Ph5‐Ring. Im Produkt 3, einer luftstabilen 17‐Elektronen‐Spezies, bindet der Phenyldichlormethyl‐Ligand im η3‐Modus nach Art eines Allylliganden.

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Unusual Thermal Reactivity of [W(CPh)(NCMe)(η²‐C₆₀)(η⁵‐C₅Ph₅)] in Chlorobenzene Involving Activation of All Ligands

Yeh

2011

Angew Chem Int Ed

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A tung(sten) twister: Heating 1 in chlorobenzene affords 2, 3, C6Ph6, and C60, and involves CH bond activation and CC bond formation of the ligands, as well as chlorine atom abstraction from the solvent. C6Ph6 is presumably generated from insertion of the benzylidyne ligand into the C5Ph5 ring. Compound 3 is an air‐stable, 17‐electron species, with the phenyldichloromethyl ligand having a unique η3‐allyl‐type bonding motif.

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Pentabenzylcyclopentadienyl molybdenum and tungsten hydrides: Syntheses, structures and electrochemistry of [MHCpBz(CO)2(L)] (L=CO, PMe3, PPh3)

Cited by 12 publications

References 69 publications

Systematic Trends in the Electrochemical Properties of Transition Metal Hydride Complexes Discovered by Using the Ligand Acidity Constant Equation

Systematic Trends in the Electrochemical Properties of Transition Metal Hydride Complexes Discovered by Using the Ligand Acidity Constant Equation

Unusual Thermal Reactivity of [W(CPh)(NCMe)(η²‐C₆₀)(η⁵‐C₅Ph₅)] in Chlorobenzene Involving Activation of All Ligands

Unusual Thermal Reactivity of [W(CPh)(NCMe)(η²‐C₆₀)(η⁵‐C₅Ph₅)] in Chlorobenzene Involving Activation of All Ligands

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Pentabenzylcyclopentadienyl molybdenum and tungsten hydrides: Syntheses, structures and electrochemistry of [MHCpBz(CO)2(L)] (L=CO, PMe3, PPh3)

Cited by 12 publications

References 69 publications

Systematic Trends in the Electrochemical Properties of Transition Metal Hydride Complexes Discovered by Using the Ligand Acidity Constant Equation

Systematic Trends in the Electrochemical Properties of Transition Metal Hydride Complexes Discovered by Using the Ligand Acidity Constant Equation

Unusual Thermal Reactivity of [W(CPh)(NCMe)(η2‐C60)(η5‐C5Ph5)] in Chlorobenzene Involving Activation of All Ligands

Unusual Thermal Reactivity of [W(CPh)(NCMe)(η2‐C60)(η5‐C5Ph5)] in Chlorobenzene Involving Activation of All Ligands

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Unusual Thermal Reactivity of [W(CPh)(NCMe)(η²‐C₆₀)(η⁵‐C₅Ph₅)] in Chlorobenzene Involving Activation of All Ligands

Unusual Thermal Reactivity of [W(CPh)(NCMe)(η²‐C₆₀)(η⁵‐C₅Ph₅)] in Chlorobenzene Involving Activation of All Ligands