Table 1.
Representative bands of sulfonamide ligand 3a and its complexes with divalent ions Zn2+, Cu2+, Co2+ and Cd2+.
| ν (cm−1) | Sulfonamide Ligand (3a) | Zinc Complex (4a) | Copper Complex (4b) | Cobalt Complex (4c) | Cadmium Complex (4d) |
|---|---|---|---|---|---|
| νN-H | 3267 (m) | - | - | - | - |
| νasSO2 | 1372 (s-m) | 1389 (s-m) | 1385 (s-m) | 1386 (s-m) | 1392 (s-m) |
| νsymSO2 | 1177 (s) | 1138 (s) | 1155 (s) | 1151 (s) | 1136 (s) |
| νC-N | 1584 (m) | 1583 (m) | 1583 (m) | 1584 (m) | 1578 (m) |
| νS-N | 927 (m) | 954 (m) | 954 (m) | 961 (m) | 957 (m) |
| νC-S | 624 (s) | 624 (s) | 629 (s) | 624 (s) | 621 (s) |
ν—stretching; s—strong; m—medium; w—weak; as—asymmetric; sym—symmetric.