Thermochemistry of molybdenum tricarbonyl complexes of arenes and cyclic polyolefins

Research output: Contribution to journalArticle

45 Citations (Scopus)

Abstract

The heats of reaction of arene, cycloheptatriene, and cyclooctatetraene complexes of molybdenum tricarbonyl with pyridine yielding (py)3Mo(CO)3 have been measured by solution calorimetry. Reaction of toluene molybdenum tricarbonyl with cyclopentadiene yielding HMo(CO)3C5H5 and with tetrahydrofuran yielding (THF)3Mo(CO)3 have also been studied thermochemically. These measurements yield accurate values for the enthalpy of arene exchange in methylene chloride solution for a number of organomolybdenum complexes. The order of stability: benzene < toluene < cyclooctatetraene < mesitylene < hexamethylbenzene < cycloheptatriene < (tris)-tetrahydrofuran < η5-cyclopentadienylhydrido < (tris)-pyridine spans a range of 31 kcal/mol. The enthalpy of isomerization of cycloheptatriene to toluene is reduced by 7.1 ± 1.2 kcal/mol upon coordination to molybdenum tricarbonyl, indicative of a loss of "resonance" energy for the complexed arene. The MoH bond strength in HMo(CO)3C5H5 is estimated as 66 ± 8 kcal/mol. The importance of entropic factors in arene exchange is discussed.

Original languageEnglish
Pages (from-to)201-214
Number of pages14
JournalJournal of Organometallic Chemistry
Volume282
Issue number2
DOIs
StatePublished - Mar 5 1985

Fingerprint

Thermochemistry
Molybdenum
thermochemistry
Polyolefins
Carbon Monoxide
molybdenum
Toluene
toluene
tetrahydrofuran
Pyridine
Enthalpy
pyridines
enthalpy
mesitylene
Dichloromethane
Calorimetry
Isomerization
Cyclopentanes
methylene
isomerization

ASJC Scopus subject areas

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

Cite this

Thermochemistry of molybdenum tricarbonyl complexes of arenes and cyclic polyolefins. / Hoff, Carl.

In: Journal of Organometallic Chemistry, Vol. 282, No. 2, 05.03.1985, p. 201-214.

Research output: Contribution to journalArticle

@article{a324c8a9c7f044c0b6286d51fbdb2654,
title = "Thermochemistry of molybdenum tricarbonyl complexes of arenes and cyclic polyolefins",
abstract = "The heats of reaction of arene, cycloheptatriene, and cyclooctatetraene complexes of molybdenum tricarbonyl with pyridine yielding (py)3Mo(CO)3 have been measured by solution calorimetry. Reaction of toluene molybdenum tricarbonyl with cyclopentadiene yielding HMo(CO)3C5H5 and with tetrahydrofuran yielding (THF)3Mo(CO)3 have also been studied thermochemically. These measurements yield accurate values for the enthalpy of arene exchange in methylene chloride solution for a number of organomolybdenum complexes. The order of stability: benzene < toluene < cyclooctatetraene < mesitylene < hexamethylbenzene < cycloheptatriene < (tris)-tetrahydrofuran < η5-cyclopentadienylhydrido < (tris)-pyridine spans a range of 31 kcal/mol. The enthalpy of isomerization of cycloheptatriene to toluene is reduced by 7.1 ± 1.2 kcal/mol upon coordination to molybdenum tricarbonyl, indicative of a loss of {"}resonance{"} energy for the complexed arene. The MoH bond strength in HMo(CO)3C5H5 is estimated as 66 ± 8 kcal/mol. The importance of entropic factors in arene exchange is discussed.",
author = "Carl Hoff",
year = "1985",
month = "3",
day = "5",
doi = "10.1016/0022-328X(85)87170-9",
language = "English",
volume = "282",
pages = "201--214",
journal = "Journal of Organometallic Chemistry",
issn = "0022-328X",
publisher = "Elsevier",
number = "2",

}

TY - JOUR

T1 - Thermochemistry of molybdenum tricarbonyl complexes of arenes and cyclic polyolefins

AU - Hoff, Carl

PY - 1985/3/5

Y1 - 1985/3/5

N2 - The heats of reaction of arene, cycloheptatriene, and cyclooctatetraene complexes of molybdenum tricarbonyl with pyridine yielding (py)3Mo(CO)3 have been measured by solution calorimetry. Reaction of toluene molybdenum tricarbonyl with cyclopentadiene yielding HMo(CO)3C5H5 and with tetrahydrofuran yielding (THF)3Mo(CO)3 have also been studied thermochemically. These measurements yield accurate values for the enthalpy of arene exchange in methylene chloride solution for a number of organomolybdenum complexes. The order of stability: benzene < toluene < cyclooctatetraene < mesitylene < hexamethylbenzene < cycloheptatriene < (tris)-tetrahydrofuran < η5-cyclopentadienylhydrido < (tris)-pyridine spans a range of 31 kcal/mol. The enthalpy of isomerization of cycloheptatriene to toluene is reduced by 7.1 ± 1.2 kcal/mol upon coordination to molybdenum tricarbonyl, indicative of a loss of "resonance" energy for the complexed arene. The MoH bond strength in HMo(CO)3C5H5 is estimated as 66 ± 8 kcal/mol. The importance of entropic factors in arene exchange is discussed.

AB - The heats of reaction of arene, cycloheptatriene, and cyclooctatetraene complexes of molybdenum tricarbonyl with pyridine yielding (py)3Mo(CO)3 have been measured by solution calorimetry. Reaction of toluene molybdenum tricarbonyl with cyclopentadiene yielding HMo(CO)3C5H5 and with tetrahydrofuran yielding (THF)3Mo(CO)3 have also been studied thermochemically. These measurements yield accurate values for the enthalpy of arene exchange in methylene chloride solution for a number of organomolybdenum complexes. The order of stability: benzene < toluene < cyclooctatetraene < mesitylene < hexamethylbenzene < cycloheptatriene < (tris)-tetrahydrofuran < η5-cyclopentadienylhydrido < (tris)-pyridine spans a range of 31 kcal/mol. The enthalpy of isomerization of cycloheptatriene to toluene is reduced by 7.1 ± 1.2 kcal/mol upon coordination to molybdenum tricarbonyl, indicative of a loss of "resonance" energy for the complexed arene. The MoH bond strength in HMo(CO)3C5H5 is estimated as 66 ± 8 kcal/mol. The importance of entropic factors in arene exchange is discussed.

UR - http://www.scopus.com/inward/record.url?scp=0000417787&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0000417787&partnerID=8YFLogxK

U2 - 10.1016/0022-328X(85)87170-9

DO - 10.1016/0022-328X(85)87170-9

M3 - Article

VL - 282

SP - 201

EP - 214

JO - Journal of Organometallic Chemistry

JF - Journal of Organometallic Chemistry

SN - 0022-328X

IS - 2

ER -