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Fragmentation and skeletal rearrangements of 2‐arylylamino‐5‐aryl‐1,3,4‐oxadiazoles and their noncovalent complexes with cobalt cation and cyclodextrin studied by mass spectrometry
Author(s) -
Frański Rafał,
Gierczyk Błażej,
Schroeder Grzegorz
Publication year - 2006
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.990
Subject(s) - chemistry , cobalt , fragmentation (computing) , electrospray ionization , stoichiometry , mass spectrometry , aryl , ion , electrospray , electron ionization , cyclodextrin , ionization , crystallography , photochemistry , inorganic chemistry , organic chemistry , chromatography , alkyl , computer science , operating system
Mass spectrometric fragmentation pathways of title compounds were studied by electron ionization (EI) and electrospray ionization (ESI) as methods of ion generation. To explain the observed complex skeletal rearrangements, tandem mass spectrometry, accurate mass measurement and isotope labeling (compounds containing one 13 C atom in oxadiazole ring) were used. Loss of CO, N 2 and H atoms under EI conditions led to the formation of 9,10‐dihydroacridine‐type ions, loss of NH 3 under ESI conditions yielded the 4‐phenylphthalazinone‐type ions and the loss of HNCO under ESI conditions produced N ‐arylamino‐benzonitrilium ions; however, this process can be affected by the electron‐donor/electron‐withdrawing properties of groups substituted at the phenyl rings. The ESI was used to study the complexes of the compounds with cobalt as well as with cyclodextrin. It was found that the compounds studied tend to form inclusion complexes with cyclodextrin of stoichiometry 1 : 1 and complexes of different stoichiometries with cobalt, although those of stoichiometry 6 : 1 and 4 : 1 are favored and the attachment of counter ion may stabilize the complexes 3 : 1 and 2 : 1. Copyright © 2006 John Wiley & Sons, Ltd.