Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Heats of reaction of Cp*(PMe/sub 3/)Ir(R)(H) (R = C/sub 6/H/sub 5/, C/sub 6/H/sub 11/, and H) with HCl, CCl/sub 4/, CBr/sub 4/, and CH/sub 3/I. A solution thermochemical study of the C-H insertion reaction

Journal Article · · J. Am. Chem. Soc.; (United States)
DOI:https://doi.org/10.1021/ja00244a046· OSTI ID:6631798
; ; ; ; ; ; ;
A number of coordinatively unsaturated transition-metal complexes have been found to insert into carbon-hydrogen bonds, leading to stable hydrido alkyl metal complexes as shown in eq 1. In such reactions, the sum of the M-H and M-C bond M + R-H ..-->.. R-M-H dissociation energies in R-M-H must be comparable to, or larger than, the energy of the alkane C-H bond which is broken. This is the driving force for C-H activation and must be on the order of 110 kcal/mol for reaction to occur. Values have been obtained for some first-row transition-metal-alkyl (=30 kcal/mol) and metal-hydride(=60 kcal/mol) bond strengths, but less information has been available for the second- and third-row metals. The authors now wish to report thermochemical studies which provide a precise value of the difference between the metal-carbon and metal-hydrogen bond energies in Cp*(PMe/sub 3/)Ir(H)(R) complexes and reasonable estimates for the absolute values of these and several other Ir-X bonds (X = H, Cl, Br, I, C/sub 6/H/sub 11/, and /sub 6/CH/sub 5/).
Research Organization:
Univ. of Miami, Coral Gables, FL
DOE Contract Number:
AC03-76SF00098
OSTI ID:
6631798
Journal Information:
J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 109:10; ISSN JACSA
Country of Publication:
United States
Language:
English

Similar Records

[beta]-Migratory insertion reactions of ([eta][sup 5]-C[sub 5]R[prime][sub 5])Rh(L)(C[sub 2]H[sub 4])R[sup +]BF[sub 4][sup [minus]] (R[prime] = H, CH[sub 3]; R = H, C[sub 2]H[sub 5]; L = P(OMe)[sub 3], PMe[sub 3]). Comparison of the energetics of hydride versus alkyl migration
Journal Article · Tue Dec 15 23:00:00 EST 1992 · Journal of the American Chemical Society; (United States) · OSTI ID:6443975
Mechanism and thermodynamics of alkane and arene carbon-hydrogen bond activation in (C/sub 5/Me/sub 5/)Rh(PMe/sub 3/)(R)H
Journal Article · Tue Mar 20 23:00:00 EST 1984 · J. Am. Chem. Soc.; (United States) · OSTI ID:6139429
Structural, kinetic, and thermodynamic study of the reversible thermal C-H activation/reductive elimination of alkanes at iridium
Journal Article · Tue Apr 01 23:00:00 EST 1986 · J. Am. Chem. Soc.; (United States) · OSTI ID:5282221

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
BROMINATED ALIPHATIC HYDROCARBONS
CARBON TETRACHLORIDE
CHEMICAL BONDS
CHLORINATED ALIPHATIC HYDROCARBONS
COMPLEXES
DATA
DISPERSIONS
ENTHALPY
EXPERIMENTAL DATA
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROCHLORIC ACID
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
IODINATED ALIPHATIC HYDROCARBONS
IRIDIUM COMPLEXES
METHYL IODIDE
MIXTURES
NUMERICAL DATA
ORGANIC BROMINE COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
PHYSICAL PROPERTIES
REACTION HEAT
SOLUTIONS
THERMODYNAMIC PROPERTIES
THERMODYNAMICS
TRANSITION ELEMENT COMPLEXES