Kinetic isotope effects as probes of the mechanism of reaction of 1-naphthylcarbene with cyclohexane and toluene

Journal Article · Wed Aug 05 04:00:00 EDT 1987 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00250a027· OSTI ID:6334748

Griffin, G W; Horn, K A

The rates of reaction of 1-naphthylcarbene (1-NC) in hydrocarbon solution have been measured with excimer laser flash photolysis of 1-naphthyldiazomethane. The kinetic data were obtained by monitoring the growth of the 1-naphthylmethyl radical (1-NCH) at 370 nm. The observed kinetic deuterium isotope effect for the reaction of 1-NC with cyclohexane (cyclohexane-d/sub 12/) in 2,2,4-trimethylpentane (k/sub H//k/sub D/ = 1.32 +/- 0.17) and the high CH insertion to H-atom abstraction product ratio are consistent with largely singlet reactivity for 1-NC. In toluene, where addition to the aromatic ring is favored over hydrogen atom abstraction, the measured inverse isotope effect (k/sub H//k/sub D/ = 0.52 +/- 0.05) also argues for predominantly singlet reactivity and a small singlet-triplet energy gap. The Arrhenius activation parameters measured for the reaction of NC with cyclohexane and toluene were E/sub act/ = 2.43 +/- 0.19 kcal/mol, log (a, s/sup -1/) = 7.70 +/- 0.15 and E/sub act/ = 1.93 +/- 0.38 kcal/mol, log (A, s/sup -1/) = 7.28 +/- 0.30, respectively.

• OSTI ID: 6334748
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 109:16; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400202* -- Isotope Effects
Isotope Exchange
& Isotope Separation
400500 -- Photochemistry
ALKANES
ALKYLATED AROMATICS
AROMATICS
ARRHENIUS EQUATION
CARBENES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CYCLOALKANES
CYCLOHEXANE
DATA
DECOMPOSITION
DEUTERIUM
DEUTERIUM COMPOUNDS
DIAZO COMPOUNDS
EQUATIONS
EXCIMER LASERS
EXPERIMENTAL DATA
GAS LASERS
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
HYDROXY COMPOUNDS
INFORMATION
ISOTOPE EFFECTS
ISOTOPES
KINETICS
LASERS
LIGHT NUCLEI
NAPHTHOLS
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHENOLS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
RADICALS
REACTION KINETICS
STABLE ISOTOPES
TOLUENE