Table 2.
The most significant bands recorded in the Raman spectra of studied CA–CD complexes (assignments were made in accordance with refs. [44,45,46,47]).
| Raman Shift/cm−1 | Band Assignments | |||
|---|---|---|---|---|
| Sample | ||||
| α-CD+CA | β-CD+CA | γ-CD+CA | 2HP-β-CD+CA | |
| 2993 | - | - | - | CH3 antisymmetric stretching |
| - | - | 2975 | 2982 | CH stretching |
| 2920 | - | - | - | |
| 2892 | 2908 | 2883 | 2881 | |
| 2956 | - | - | - | CH stretching or wagging |
| - | 2939 | 2932 | 2931 | CH2 antisymmetric stretching, CH3 symmetric stretching |
| 2918 | - | - | - | CH stretching or wagging |
| - | - | - | 2866 | CH2 symmetric stretching |
| - | - | 2839 | 2839 | CH3 stretching |
| 1476 | - | 1472 | - | CH deformational |
| 1456 | 1449 | 1453 | 1456 | CH2 deformational |
| - | 1414 | 1400 | 1403 | C–O–C symmetric and antisymmetric stretching |
| - | 1389 | - | - | C–H stretching or wagging |
| 1366 | - | 1370 | - | C–C stretching and ring deformation |
| - | - | - | 1346 * | Deformations of the CH2OH group, C–O, C–N stretching |
| 1331 | 1335 | 1327 | 1335 | CH2 deformational |
| 1264 | - | 1264 | 1267 | C=O stretching |
| 1244 | 1248 | - | - | C=O stretching, CH in plane bending of the aromatic rings, OH in plane bending, CH2 stretching |
| - | - | 1157 * | - | –C=C–H antisymmetric angular deformation in plane, furanyl ring in CA |
| 1137 | - | 1133 | 1142 | C-O-C stretching |
| 1127 | 1127 | - | 1126 | C–O–C symmetric stretching |
| - | 1111 | 1109 | - | C–O–C symmetric and antisymmetric stretching of glycosidic bonds |
| 1081 | 1083 | - | 1082 | |
| 1057 1036 |
1046 | 1040 | 1040 | C–O stretching |
| - | 1000 * | - | - | “breathing mode” of the aromatic carbon ring, C=C–H stretching |
| - | - | 969 * | - | C–H and C–OH deformational |
| 952 | 948 | 948 | 948 | Skeletal mode of α-(1–4) linkage (delocalized mode), C–O stretching |
| 938 864 |
926 864 |
917 - |
925 - |
Glucopyranose (C–O–C) skeletal mode of α-anomers |
| 854 | 851 | 858 | 852 | Skeletal vibrations, OCH side group deformational of d-glucopyranose units, CNC symmetric stretching of the imide |
| 843 | - | - | - | C–O–C antisymmetric stretching |
| 749 | 756 | 757 | 759 | d-glucopyranose ring breathing mode and C–C central stretch |
| 708 | 710 | 706 | 707 | C–H out-of-plane bending of CA |
| 609 * | - | - | - | C–C–C ring in-plane bending of CA |
| - | 588 | 592 | 590 | Symmetric oxygen breathing vibration, C–O bending |
| 570 | 571 | - | - | OH wagging |
| - | - | 513 * | - | In-plane C–C stretching and ring deformation of CA |
| 496 | 497 | - | 496 | C–C–C bending |
| 479 | 477 | - | 478 | Skeletal vibrations, amylose |
| 456 | 439 | - | 443 | CH stretching |
| 416 357 |
- 363 |
427 - |
- 234 |
OH stretching |
| 389 | - | 374 | - | C–C stretching |
| - | 321 * | - | External C–OH out of plane bending of glucopyranose units | |
| 310 | - | 302 | - | C–C antisymmetric stretching |
| 286 | - | 272 | - | C–O stretching |
| 153 * | - | - | - | Breathing motions of oxygen atoms in the macrocyclic ring |
| 138 * | - | - | - | Stretching or bending vibrations of hydrogen bonds |
Asterisks (*) indicate the most significant differences between the samples.