Table 2 Spectral characteristics of nanosilica-immobilized Schiff bases and \( \mathrm{M}\mathrm{n}{\left(\mathrm{L}\right)}_2/\overline{\mathrm{Si}} \) complexes
Ligand complex | Wave numbers of peak maximums, cm−1 | |
|---|---|---|
ν C=N | ν π − π* | |
L1 | 1635 | 24,600 |
\( \mathrm{M}\mathrm{n}{\left(\mathrm{L}1\right)}_2/\overline{\mathrm{Si}} \) | 1630 | 24,900 |
L2 | 1642 | 29,700; 23,900; 19,400 |
\( \mathrm{M}\mathrm{n}{\left(\mathrm{L}2\right)}_2/\overline{\mathrm{Si}} \) | 1630 | 29,800; 24,000; 19,600 |
L3 | 1640 | 23,600; 25,400 |
\( \mathrm{M}\mathrm{n}{\left(\mathrm{L}3\right)}_2/\overline{\mathrm{Si}} \) | 1630 | 23,600; 25,400 |
L4 | 1650 | 23,600 |
\( \mathrm{M}\mathrm{n}{\left(\mathrm{L}4\right)}_2/\overline{\mathrm{Si}} \) | 1645; 1620 | 24,800; 25,000 |
L5 | 1650 | 23,960 |
\( \mathrm{M}\mathrm{n}{\left(\mathrm{L}5\right)}_2/\overline{\mathrm{Si}} \) | 1630 | 24,300 |
L6 | 1650; 1600 | 25,000 |
\( \mathrm{M}\mathrm{n}{\left(\mathrm{L}6\right)}_2/\overline{\mathrm{Si}} \) | 1665; 1600 | 27,200; 25,600 |