Publicação
Cation coordination and hydrogen bonding in potassium and magnesium-based di-amidosil hybrids
| Resumo: | Fourier transform mid-infrared and Raman spectroscopies were employed to elucidate the cation/ alkylene chains, cation/cross-link, cation/anion interactions and hydrogen bonding occurring in amorphous di-amide cross-linked alkylene/siloxane hybrid materials (di-amidosils) doped with potassium and magnesium triflates (KCF3SO3 and Mg(CF3SO3)2, respectively). Materials with compositions oo > n > 5 (where n expresses the molar ratio of carbonyl oxygen atoms per guest cation) were investigated. The conformations (gauche) of the alkylene el-iains of the host di-amidosil matrix are not affected by the presence of the guest salt in both doped di-amidosil families. The K+ and Mg2+ ions coordinate to the carbonyl oxygen atoms of the amide cross-links within the whole range of salt concentration considered, leading to the saturation of the cross-linkages, to a redistribution of the amide-amide hydrogen-bonded aggregates of the host matrix and, in the case of the K+-doped sample with n = 10, to the formation of a new type of aggregate, stronger and more ordered than those detected at lower salt content. In both di-amidosil systems guest salt addition leads to the increase of ionic associated species and to a concomitant decrease of the concentration of "free" anions. |
|---|---|
| Autores principais: | Nunes, Sílvia |
| Outros Autores: | Zea Bermudez, V. de; Ostrovskii, David; Carlos, Luís; Silva, Maria Manuela; Smith, Michael John |
| Assunto: | Sol-gel process Magnesium triflate Potassium triflate FT-IR FT-Raman di-amidosils magnesium and potassium triflates |
| Ano: | 2008 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Fourier transform mid-infrared and Raman spectroscopies were employed to elucidate the cation/ alkylene chains, cation/cross-link, cation/anion interactions and hydrogen bonding occurring in amorphous di-amide cross-linked alkylene/siloxane hybrid materials (di-amidosils) doped with potassium and magnesium triflates (KCF3SO3 and Mg(CF3SO3)2, respectively). Materials with compositions oo > n > 5 (where n expresses the molar ratio of carbonyl oxygen atoms per guest cation) were investigated. The conformations (gauche) of the alkylene el-iains of the host di-amidosil matrix are not affected by the presence of the guest salt in both doped di-amidosil families. The K+ and Mg2+ ions coordinate to the carbonyl oxygen atoms of the amide cross-links within the whole range of salt concentration considered, leading to the saturation of the cross-linkages, to a redistribution of the amide-amide hydrogen-bonded aggregates of the host matrix and, in the case of the K+-doped sample with n = 10, to the formation of a new type of aggregate, stronger and more ordered than those detected at lower salt content. In both di-amidosil systems guest salt addition leads to the increase of ionic associated species and to a concomitant decrease of the concentration of "free" anions. |
|---|