Nature of methyl cation bonding to dihydroxybenzenes elucidated using an ion trap mass spectrometer

✍ Scribed by B. D. Nourse; J. S. Brodbelt; R. G. Cooks

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 681 KB
• Volume: 26
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/oms.1210260608

✦ Synopsis

Methylation of the isomeric dihydroxybenzenes using the dimethylfluoroaium ion (I CH,FCH,I +) was studied in a quadrupole ion trap mpss spectrometer. The products were characterized by tandem mass spectrometry lsing collision-activated dissociation. A comparison of the daughter ion spectra of the methylated products with those of model ions, generated by protomtion of substituent-and ring-methylated analogs, demonstrates that a mixture of methylated products is generated. Included are structures in which the methyl is a-bonded to the ring and others with a-bonds to tbe heteroatom, the latter being favored in catecbol and bydroquinooe. Tbe energy-resolved daughter ion spectra for the methylated isomers, acquired by varying the amplitude of the ax.. voltage used to excite resonantly the mass-selected ions, support tbese conclusions regarding the site of methylation.