The formation and structure of radical cations

Abstract

[C,H,N]? ions generated from a number of different precursors have been studied by high kinetic energy ion-molecule reactions. It has been shown that at least four distinct stable species occur, of which acetonitrile and methyl isocyanide retain their original structure. With imidazole or pyrazole as precursors, a mixture of open chain radical cations, not identical to the above species and probably interconvertible via the 1H-azirine radical cation, is formed. From butyronitrile, pyrrole, crotonitrile, ally1 cyanide, methacrylonitrile and cyanocyclopropane a fourth species, probably the vinylidenimine ion, is formed

VUV photophysics and dissociative photoionization of pyrimidine, purine, imidazole and benzimidazole in the 7–18eV photon energy range

“…Bowie et al [64] have proposed that m/z = 41 is a cyclic ion, the 1H-azirine radical cation. In their EI-MS study, van Thuijl et al [65] suggested that the m/z = 41 ion formed from imidazole is a mixture of open chain radical cations, of the HC@CHNH + type, probably interconvertible via the 1H-azirine radical cation. We suggest that at onset the C 2 H 3 N þ ion has the structure CH 2 -C + @NH (since CH@N-CH þ 2 can be eliminated, see below) remarking that at higher energies the structure of the molecular radical cation C 3 H 4 N þ 2 may have changed and that products with another structure might appear.…”

Fragmentation d'azoles sous l'impact electronique VI–indazole

“…Etant donnt la similitude des spectres des azoles I et IV et la possibilitt de conversion I -+ IV par voie photochimique,2 un m&me type d'isomtrisation pourrait &re envisagt pour expliquer le comportement de I sous l'impact tlectronique. (1,2), 65 (2,9), 64(10,6), 63(11,0), 62 (4,2). 61 (1,9), 59(5,1), 52(4,6), 51(1,7), 50(2,0), 45,503, 41(2,0), WO,9), 39(5,1), 38(4,2), 37(2,5), 28(2,5), 27(2,6), 26(0,7).…”

“…Zndazole-1-d @I) 120(9,1), 119(100,0), 118(8,6), 117(0,9), 93 (1,4), 92(15,3), 91(15,5), 90(3,7), 89(1,2), 78(1,6), 66(2,2), 65(6,2), 64(9,7), 63(11,3), 62(4,2), 61(2,0), 59,5(5,5), 59(1,1), 53(3,7), 52(2,3), 51(13), 50 (1,9), 44(2,5), 42 (1,9) isomtrisation thermique de I avant l'ionisation en mtlangeant ce produit avec un excts d'eau lourde dans le systtme &introduction. Aucune double deuttriation n'est mise en tvidence, alors que, dans des conditions identiques, l'o-cyanoaniline incorpore aistment un et deux atomes de deuttrium.…”

“…, 41(2,0), 40(1,6), 39(4,8), 38(4,8), 37(2,4).Zndazole-3-d (111) 121[1,3), 120(15,7), 119(100,0), 118(25,0), 117(1,3), 93(2,8), 92(15,7), 91(21,3), 90(6,7), 89(1,8), 78(1 ,7), 66(2,0), 65(7,4), 64(19,6), 63(17,6), 62(6,7), 61(3,0), 59,5(4,5), 59U ,@, 53(2,1), 52(7,1), 51(3,7), 50(2,8), 44(4,7), 41(3,7), 4 0 ( 4 , 0 ) , 39(8,8), 38(7,9), 37(3,8). En ce qui concerne les ions fragments 'normaux,' on observe une Climination de HCN et DCN dans un rapport quasi unitaire au depart des ions moltculaires de I1 et 111.…”

The generation of neutral and ionized allenes, cumulenes and heterocumulenes by electron impact

“…This is a process the proportion of which depends on the ionization energy. The elimination of t-butylketene from 92 Thorough investigations of the derivatives of urea48, semi~arbazone~~ and thios e r n i c a r b a~o n e~~ revealed that the neutral X=C=Y (X = NH, CH2; Y = 0, S) is easily generated by electron impact. An unusual elimination of t-butyl isocyanate, respectively isocyanic acid and isobutylene from phenoxyacetamide (109) was investigated by Tamers' (Scheme 25).…”