Electron Impact Induced Cyclization of ortho-Substituted Diphenylmethanes

Article abstract of DOI:10.1002/oms.1210160308

Mass spectra of 2-hydroxydiphenylmethane and its derivatives are characterized in the upper mass region by an abundant ion m/z 165.Metastable ion measurements reveal that this ion is formed from the molecular ion of the parent compound by elimination of H2O and hydrogen.A fluorenyl cation structure is proposed for this ion on the basis of identity of collision induced mass analyzed ion kinetic energy spectra of ion m/z 165 generated from 2-hydroxydiphenylmethane and from fluorene.Four different pathways of formation of a fluorenyl cation are discussed.The contribution of each of these to the genesis of fragment m/z 165 was monitored in a reversed geometry instrument by measuring the first fragmentation in the first field free region and the second fragmentation in the second field free region.