| Abstrakt: |
The mass spectra of two series of functional benzene derivatives with tert-butyl substituents in the 4-position (p-Me3CC6H4X, X = COCl, COOH, COSH, COSCD3, CSSMe, CSCMe3) or in the 3,5-positions 3,5-(Me3C)2C6H3X (X = CMe3, Br, CN, CH2Cl, CH2Br, CHO, COCH3, CONMe2, CSNMe2) have been studied. Ionization energies and appearance energies of some fragment ions were measured by photoionization mass spectrometry. The heats of formation of [p-Me3CC6H4C≡O]+(579 kJ mol−1) and [p-Me3CC6H4C≡S]+(840 kJ mol−1) ions have been derived. It was demonstrated that the former ion is 30 kJ mol−1more stable than the latter one in the framework of isodesmic reactions. Isodesmic reactions were used to prove that the [M – Me]+ions from p-Me3CC6H4CSCMe3possess the structure [Me3CC6H4C(SH)CH=CH2]+at the threshold of their formation. The appearance of abundant Me3C+and X+ions from 3,5-(Me3C)2C6H3X is explained by involvement of rearrangement rather than simple bond cleavage processes. |
