An investigation by ion cyclotron double resonance of the structural differences of isomeric ions using a direct insertion probe

Abstract

Ions (I) and (II) of m/e 152 obtained by electron impact from 1-methyl-4-nitroimidazole-5-carbonitrile and from 1-methyl-4-nitroimidazole-5-carboxamide were separately caused to react with 3,5-dimethylpyridine. Ion (I) reacted only by charge transfer, while ion (II) reacted both by charge transfer and by proton transfer with the base. The different behaviour under identical conditions proved the non-identity of the two ions. As the substances investigated were solids, a direct insertion probe had to be used in the experiments.