Synthesis and thermochemistry of HMo(CO)3C5Me5; Comparison of cyclopentadienyl and pentamethylcyclopentadienyl ligands

Steven P. Nolan, Carl Hoff, John T. Landrum

Research output: Contribution to journalArticle

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Abstract

Toluenemolybdenum tricarbonyl reacts quantitatively with pentamethylcyclopentadiene in THF at room temperature yielding HMo(CO)3C5Me5. The heat given off in this reaction has been measured by solution calorimetry and indicates there is little difference in the MoC5H5 and MoC5Me5 bond strengths. Thermochemical measurements of the reaction of HMo(CO)3C5R5 (R = H, CH3) with pyridine yielding (py)3Mo(CO)3 confirm this result. In THF solution, HMo(CO)3C5Me5 is a weaker acid than HMo(CO)3C5H5, ΔpKa ≥ 3. The heat of hydrogenation of (Mo(CO)3C5R5)2 to yield two mol of HMo(CO)3C5R5 is more favorable by about 2 kcal/mol for R = CH3 compared to R = H, probably due to steric repulsion in (Mo(CO)3C5Me5)2.

Original languageEnglish
Pages (from-to)357-362
Number of pages6
JournalJournal of Organometallic Chemistry
Volume282
Issue number3
DOIs
StatePublished - Mar 12 1985

Fingerprint

Thermochemistry
thermochemistry
Carbon Monoxide
Ligands
heat
ligands
Calorimetry
synthesis
Pyridine
Hydrogenation
hydrogenation
pyridines
heat measurement
acids
Acids
room temperature
Hot Temperature
Temperature

ASJC Scopus subject areas

  • Biochemistry
  • Chemical Engineering (miscellaneous)
  • Inorganic Chemistry
  • Organic Chemistry
  • Physical and Theoretical Chemistry
  • Materials Science (miscellaneous)
  • Materials Chemistry

Cite this

Synthesis and thermochemistry of HMo(CO)3C5Me5; Comparison of cyclopentadienyl and pentamethylcyclopentadienyl ligands. / Nolan, Steven P.; Hoff, Carl; Landrum, John T.

In: Journal of Organometallic Chemistry, Vol. 282, No. 3, 12.03.1985, p. 357-362.

Research output: Contribution to journalArticle

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abstract = "Toluenemolybdenum tricarbonyl reacts quantitatively with pentamethylcyclopentadiene in THF at room temperature yielding HMo(CO)3C5Me5. The heat given off in this reaction has been measured by solution calorimetry and indicates there is little difference in the MoC5H5 and MoC5Me5 bond strengths. Thermochemical measurements of the reaction of HMo(CO)3C5R5 (R = H, CH3) with pyridine yielding (py)3Mo(CO)3 confirm this result. In THF solution, HMo(CO)3C5Me5 is a weaker acid than HMo(CO)3C5H5, ΔpKa ≥ 3. The heat of hydrogenation of (Mo(CO)3C5R5)2 to yield two mol of HMo(CO)3C5R5 is more favorable by about 2 kcal/mol for R = CH3 compared to R = H, probably due to steric repulsion in (Mo(CO)3C5Me5)2.",
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AU - Nolan, Steven P.

AU - Hoff, Carl

AU - Landrum, John T.

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N2 - Toluenemolybdenum tricarbonyl reacts quantitatively with pentamethylcyclopentadiene in THF at room temperature yielding HMo(CO)3C5Me5. The heat given off in this reaction has been measured by solution calorimetry and indicates there is little difference in the MoC5H5 and MoC5Me5 bond strengths. Thermochemical measurements of the reaction of HMo(CO)3C5R5 (R = H, CH3) with pyridine yielding (py)3Mo(CO)3 confirm this result. In THF solution, HMo(CO)3C5Me5 is a weaker acid than HMo(CO)3C5H5, ΔpKa ≥ 3. The heat of hydrogenation of (Mo(CO)3C5R5)2 to yield two mol of HMo(CO)3C5R5 is more favorable by about 2 kcal/mol for R = CH3 compared to R = H, probably due to steric repulsion in (Mo(CO)3C5Me5)2.

AB - Toluenemolybdenum tricarbonyl reacts quantitatively with pentamethylcyclopentadiene in THF at room temperature yielding HMo(CO)3C5Me5. The heat given off in this reaction has been measured by solution calorimetry and indicates there is little difference in the MoC5H5 and MoC5Me5 bond strengths. Thermochemical measurements of the reaction of HMo(CO)3C5R5 (R = H, CH3) with pyridine yielding (py)3Mo(CO)3 confirm this result. In THF solution, HMo(CO)3C5Me5 is a weaker acid than HMo(CO)3C5H5, ΔpKa ≥ 3. The heat of hydrogenation of (Mo(CO)3C5R5)2 to yield two mol of HMo(CO)3C5R5 is more favorable by about 2 kcal/mol for R = CH3 compared to R = H, probably due to steric repulsion in (Mo(CO)3C5Me5)2.

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