ELECTRON-IMPACT INDUCED FRAGMENTATION OF DIBENZO CROWN-ETHERS

Six structurally related crown ethers have been studied by electron im pact (EI) mass spectrometry, From accurate mass measurements, metastab el ion and mass-analyzed ion kinetic energy (MIKE) spcctra, plausible fragmentation pathways were deduced, All compounds showed very abundan t molecular ions and some amount of the doubly charged molecular ions, The primary fragmentations always involved the catechol moiety and co nsequent loss of oxirane although the fragment(ation)s also showed a c lear dependence on the functionalities X in one of the crown ether seg ments, -OCH(2)XCH(2)O- (compound/X: 1/-CH2-, 2/-C=C-, 3/trans-CH=CH-, 4/cis-CH=CH-, [GRAPHICS] and 6/-CH2CH2-).