Intermediates in the decomposition of aliphatic diazo-compounds. Part 20. Kinetic studies on reductively initiated electron transfer chain catalysis of the decomposition of 9-diazofluorene

Abstract

The method of constant-current electrolysis (c.c.e.) at a platinum cathode has been used to investigate the kinetics of the electron transfer chain catalysis of the decomposition of 9-diazofluorene (FIN₂) in CH₃CN solution. Equations have been derived for various possible kinetic forms of both chain propagation and termination, and comparison with observation indicates that the chain carrier reacts with a molecule of FIN₂ to propagate the chain and reacts with the solvent, or other additive such as oxygen or diethyl malonate, to terminate the chain. Interruption of the current in the experiments (i.c.c.e.) leads to a different set of equations from which it is possible to evaluate separately the rate constants for propagation and termination. The identity of the chain carrier is discussed. It is established that this is unlikely to be the diazolalkane anion radical, FIN₂^–˙, as previously thought. Anion-radicals derived from the product fluorenone azine are the likeliest candidates under the reaction conditions used.