TY - JOUR AB - Metastable [M - H]+ ions of alpha,omega-diphenylalkanes C6H5(CH2)xC6H5 where x = 3-6 (structures 3-6 respectively), generated by hydride abstraction in the chemical ionization (i-butane) source, eliminate benzene after proton exchange between the aromatic rings. The proton exchange is slow for ions [3 - H]+ and [4 - H]+, but fast and apparently complete for ions [5 - H]+ and [6 - H]+. These observations, combined with collision activation experiments, suggest the cyclization of the [M - H]+ ions to isomeric protonated 1-phenylbenzocycloalkane and 1-benzylbenzocycloalkane derivatives, i.e. to [M1 + H]+ type ions, with a preference for protonated tetralin structures. Hydrogen exchange between the aliphatic chain and the rings is absent or negligible for [M - H]+ ions of 3-5 but is significant for ions [6 - H]+. DA - 1992 DO - 10.1016/0168-1176(92)80107-C KW - Cyclization KW - Gas phase KW - Mechanisms KW - Diphenylalkanes KW - Proton exchange LA - eng IS - 1-3 M2 - 441 PY - 1992 SN - 0168-1176 SP - 441-455 T2 - International Journal of Mass Spectrometry and Ion Processes TI - Gaseous [M - H]+ ions of alpha,omega-diphenylalkanes: cyclization to [M + H]+ type ions of benzocycloalkanes as recognized by chain-length dependent proton exchange UR - https://nbn-resolving.org/urn:nbn:de:0070-pub-17743110 Y2 - 2024-11-22T04:52:01 ER -