Influence of oxidation state of sulfur on the dissociation of [Tz-(CH2)n-S(O)m-(CH2)n-Tz + Na+] adducts generated by electrospray ionization (Tz = tetrazole ring; n = 2, 3; m= 0, 1, 2).
Sodium adducts of six organosulfur-α,ω-ditetrazole compounds (Tz-(CH(2))(n)-S(O)(m)-(CH(2))(n)-Tz; where Tz = tetrazole ring; n = 2, 3; m = 0, 1, 2) were generated via electrospray ionization (ESI) and their fragmentation pattern assessed via collision-induced dissociation (CID). Two main dissociation channels were observed: (a) losses of N(2) and HN(3) from the tetrazole rings; (b) cleavage of the C-S bond. The sulfoxides pass predominantly through the second fragmentation pathway, but for the sulfides and sulfones the tetrazole ring fragmentation occurs. Theoretical calculations at the B3LYP/6-31 + G(d,p) level indicate that for all the adducts (sulfide, sulfoxide, and sulfone) the dissociation pathway that leads to product ions arising from loss of N(2) was the most exothermic. Based on these results and assumptions, it was postulated that the dissociation of the sulfoxide adducts occurs under kinetic control (N(2)-loss pathway via a much more energetic transition state). For the sulfide and sulfone adducts, on the other hand, the dissociation process takes place via a thermodynamically controlled process.
Departamento de Química, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte/MG, Brazil, 31270-901. shetq@yahoo.com.br
Sheila Rodrigues
SR
Oliveira
Luciano José
LJ
Nogueira
Rodinei
R
Augusti
Maria Aparecida de Resende
MA
Stoianoff
Charles Martins
CM
Aguilar
Willian Ricardo
WR
Rocha
Claudio Luis
CL
Donnici
D007477:Ions / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013455:Sulfur / Q000737:chemistry*; D013457:Sulfur Compounds / Q000737:chemistry*; D053719:Tandem Mass Spectrometry; D013777:Tetrazoles / Q000737:chemistry*
D007477:Ions; D013457:Sulfur Compounds; D013777:Tetrazoles; D013455:Sulfur