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 language | English |
|---|---|
| Pages (from-to) | 201-214 |
| Number of pages | 14 |
| Journal | Journal of Organometallic Chemistry |
| Volume | 282 |
| Issue number | 2 |
| DOIs | |
| State | Published - Mar 5 1985 |
Fingerprint
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 journal › Article
}
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 -