Kinetics, deuterium isotope effect and mechanism of the proton transfer reaction of bis-(2,4-dinitrophenyl)methane with pentaisopropylguanidine in aprotic solvents

The rate constants, deuterium isotope effect, activation parameters and mechanism of proton and deuteron transfer reaction from bis-(2,4-dinitrophenyl)methane (1) to pentaisopropyloguanidine in toluene, chloro benzene and tetrahydrofuran are reported. Deuterium isotope effects for measured reactions at 25 C are 10.2, 8.4 and 12.6 in toluene, chloro benzene and THF respectively. The results obtained for reaction of (1) with pentaisopropylguanidine are compared with rate constants, isotope effects and activation parameters for the reaction of (1) with tetramethyl guanidine. Influence of steric hindrance on the kinetic results are discussed. (author). 23 refs, 5 tabs