Chemically activated 1,1‐dimethylcyclopropane from photolysis of isobutene–neopentane–diazomethane–oxygen mixtures

Abstract

A study of the structural isomerization rate of chemically activated 1, I-dimethylcyclopropane from singlet methylene addition to the double bopd of isobutene is reported. Singlet methylenes were produced from the 4358-and 3660-A photolysis of diazomethane in the presence of added oxygen. Theoretical rates calculated via RRKM theory are in excellent agreement with experiment for calculations utilizing activated complex structures and critical energies consistent with known thermal Arrhenius parameters, and excitation energies consistent with previous determinations of aHP,(CH2) , + E*(CH2) = 116.1 and 112.6 kcal/mole for diazomethane photolyses at 3660 and 4358 A, respectively.

Vibrational energy distributions of reacting CH2(1A1) from the 4358, 3660, and 2537 .ANG. photolyses of CH2N2 and upon reaction with cyclobutane. A chemical activation study

“…Any ground state CH2(3Bi) produced in the initial photolyses are scavenged by added oxygen. 8 Step 2 occurs for each initial energy level, /, while steps 3 and 4 occur for every level of energy j.…”

Thermal Isomerizations of 1,1-Dimethyl-2,2-d2-cyclopropane

“…Work on the chemically activated isomerization of 1 has served as a testing ground for RRKM theory. , …”

“…1 Work on the chemically activated isomerization of 1 has served as a testing ground for RRKM theory. 4,5 The isomerization of 1 has been a veritable fixed point in related hydrocarbon thermal rearrangement chemistry shown by other alkyl-and dialkyl-substituted cyclopropanes, [6][7][8] so long known, well studied, and thoroughly understood that it has not been subjected to experimental or theoretical re-examination in recent decades. One step in this direction is now reported, based on the reactions shown by 1 and by 1,1-dimethyl-2,2-…”