CFA FCT/UNL is one of the two scientific groups of Centro de Física Atómica (CFA). Most of its members belong to Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa (FCTUNL).
Azidoacetone as a complexing agent of transition metals Ni2+/Co2+ promoted dissociation of the C-C bond in azidoacetone
| Title | Azidoacetone as a complexing agent of transition metals Ni2+/Co2+ promoted dissociation of the C-C bond in azidoacetone |
| Publication Type | Journal Article |
| Year of Publication | 2011 |
| Authors | Assis, Ana C., Couto Narciso, Duarte Filomena M., Rodrigues Paula, Barros Teresa M., Costa Lourdes M., Cabral Benedito J. C., and Fernandez Tereza M. |
| Journal | Journal of Mass Spectrometry |
| Volume | 46 |
| Pagination | 696-704 |
| ISBN Number | 1096-9888 |
| Keywords | azidoacetone complexes, C-C metal insertion, DFT calculations, electrospray ionization, tandem mass spectrometry |
| Abstract | The relevance of metal interactions with azides has led us to the study of the complexation of some transition metals, nickel and cobalt, by azidoacetone by means of electrospray ionization mass spectrometry (ESI-MS). Complexes were obtained from solutions of NiCl2 and CoCl2, in methanol/water. Nickel was electrosprayed with other counter ion, bromide (Br), as well as other solvent (ethanol/water). For nickel and cobalt, the complexes detected were single positively charged, with various stoichiometries, some resulted from the fragmentation of the ligand, the loss of N2 being quite common. The most abundant species were [Ni(II)Az2X]+ where X = Cl, Br and Az = azidoacetone. Some of the complexes showed solvation with the solvent components. Metal reduction was observed in complexes where a radical was lost, resulting from the homolytic cleavage of a metal coordination bond. Collision-induced dissociation (CID) experiments followed by tandem mass spectrometry (MS-MS) analysis were not absolutely conclusive about the coordination site. However, terminal ions of the fragmentation routes were explained by a gas-phase mechanism proposed where a CC bond was activated and the metal inserted subsequently. Density functional theory calculations provided structures for some complexes. In [Ni(II)Az2X]+ species, one azidoacetone ligand is monodentate and the dominant binding location is the alkylated nitrogen and not the carbonyl group. The other azidoacetone ligand is bidentate showing coordination through alkylated nitrogen and the carbonyl group. These are also the preferential binding sites for the most stable isomer of [Ni(II)AzX]+ species. Copyright © 2011 John Wiley & Sons, Ltd. |
| URL | http://dx.doi.org/10.1002/jms.1940 |
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