Gas-Phase Ion—molecule Reactions of C₆₀ with the Plasma of Methyl Acrylate

Abstract

The gas-phase ion-molecule reactions of C 60 with the plasma generated from methyl acrylate under self-chemical ionization conditions were studied by use of a triple-quadrupole mass spectrometer. The adduct cation [C 60 C 3 H 3 O] + and protonated molecular ion [C 60 H] + were observed as the major product ions. The former adduct ion is formed by electrophilic reaction of C 60 with the ion [CH 2 =CHCO] + , a main fragment ion resulting from the methyl acrylate molecular ion [CH 2 =CHCOOCH 3 ] + through alpha cleavage. The latter ion is generated by proton transfer from protonated methyl acrylate to C 60. Semi-empirical quantum chemical calculations have been performed for the eight possible isomers of [C 60 C 3 H 3 O] + at the Hartree-Fock level by use of the AM1 method. The results show three types of cycloadducts as the most stable structures among the possible isomers.

A Comparative Study of Homolytic Reactions of Fullerenes with Aldehydes in a Mass Spectrometer under Electron Impact and in Solution under UV Irradiation

“…This resulted in the fact that they observed the products of ion/molecule reactions of the fullerenes with fragment ions, sometimes with the molecular and even higher mass ions, of the compounds used as reagent gases (acetone, vinyl acetate, benzene, alkyl methyl ethers, aliphatic primary alcohols, methyl acrylate, trimethylsilyl methyl ether, haxamethyldisiloxane and carbon disulfide). [18][19][20][21][22]48,49 Contrary to this, in all our studies of the reactions of fullerenes with other species, including aldehydes in the EI ion source of a mass spectrometer, we detected the products of other types, namely those from homolytic reactions between the reactants. The Chinese chemists did not work with aldehydes.…”

“…[8][9][10][11][12][13][14][15] Another group of ion/molecule reactions was observed in the course of chemical ionization (CI) studies of fullerenes, 16,17 including those implemented under conditions of self-CI in which a number of organic compounds were used as reagent gases. 11,[18][19][20][21][22] The interaction of C 60 and C 70 with O 2 to give C 60 O n − and C 70 O m − adducts, respectively, in the negative CI source of a mass spectrometer occurred, in all likelihood, through an ion/molecule mechanism. 23 However, from the point of view of the possibility of implementing reactions occurring in mass spectrometers in solution, the most profitable ones are homolytic, since they are less dependent on solvents than ionic reactions.…”