S. No. | Modea | Obs. freq. (cm−1) | Cal. freq. (cm−1) | IRb(Ii) | Ramanc(Ai) | Vibrational assignmentd | ||
IR | Raman | Unscaled | Scaled | |||||
Aromatic nucleus-in-plane vibrations | ||||||||
1 | ν(C-C) 1 | 655 | 675 | 701 | 691 | 28.75 | 5.88 | 1(58) + 12(18) + 7a(12) |
2 | ν(C-C) 8a | 1567 | 1571 | 1585 | 1594 | 55 | 28.23 | 8a(51) + 7b(27) + 6a(12) + 7a(11) |
3 | ν(C-C) 8b | 1621 | 1625 | 1652 | 1658 | 85 | 70.58 | 8b(65) + 18b(12) + 6b(11) |
4 | ν(C-C) 14 | 1267 | 1264 | 1254 | 1254 | 87.5 | 24.7 | 14(49) + 3(26) + 12(10) |
5 | ν(C-C) 19a | - | - | 1464 | 1474 | 14.16 | 20.61 | 19a(73) + 7a(19) |
6 | ν(C-C) 19b | 1497 | 1494 | 1541 | 1520 | 78.75 | 9.411 | 19b(56) + 18b(23) |
7 | ν(C-H) 2 | - | 3087 | 3207 | 3083 | 25.12 | 29.41 | 2(99) |
8 | ν(C-H) 20a | 3090 | - | 3204 | 3067 | 56.25 | 13.79 | 20a(99) |
9 | ν(C-H) 20b | 3065 | 3067 | 3183 | 3063 | 53.75 | 11.76 | 20b(99) |
10 | ν(C-Cα) 13 | 1201 | 1204 | 1176 | 1180 | 40 | 17.64 | 13(38) + 3(34) + ν(Cα-OH)(16) |
11 | ν(C-N) 7a | 1138 | 1140 | 1160 | 1140 | 45 | 3.52 | 6a(26) + 19a(18) + 7a(15) + 7b(10) |
12 | ν(C-C') 7b | - | - | 1280 | 1293 | 36.8 | 31 | 14(30) + 7b(19) + 18b(15) |
13 | β(CH) 3 | 1296 | 1292 | 1203 | 1275 | 91.25 | 28.53 | 3(35) + 12(22) + 14(16) |
14 | β(CH) 18a | 1168 | 1168 | 1106 | 1134 | 37.5 | 23.52 | 18a(45) + 8a(18) + 6a(12) + ν(Cα-OH)(10) |
15 | β(CH) 18b | 1090 | 1074 | 1090 | 1084 | 57.05 | 4.7 | 19b(30) + 18b(18) + ν(Cα-OH)(10) |
16 | β(CCα) 15 | - | - | 268 | 265 | 17.21 | 30.21 | 12(26) + 15(24) + 9b(21) + δ(Cα-OH)(13) |
17 | β(CN) 9b | - | - | 338 | 336 | 21.61 | 22.21 | 9b(32) + γ(NO2)(24) + δ(Cα-OH)(13) + 15(10) |
18 | β(CC') 9a | - | 343 | 352 | 360 | 2.21 | 8.235 | 9a(25) + 6a(25) + 7a(19) + δ(Cα-OH)(12) |
19 | β(CCC) 6a | - | 508 | 482 | 478 | 21 | 7.058 | 6a(45) + δ(Cα-OH)(23) + γ(NO2)(18) |
20 | β(CCC) 6b | - | 377 | 397 | 390 | 2.13 | 20 | 1(31) + 6b(19) + 9a(14) + δ(Cα=O)(10) |
21 | β(CCC) 12 | 805 | 814 | 789 | 789 | 23.75 | 75.29 | 12(31) + δ(NO2)(15) + 1(15) + 13(11) |
Aromatic nucleus-out-of-plane vibrations | ||||||||
22 | π(CH) 5 | 830 | 856 | 877 | 871 | 47.5 | 3.52 | 5(84) |
23 | π(CH) 11 | 744 | 759 | 762 | 766 | 81.25 | 4.7 | 11(84) |
24 | π(CH) 17b | 948 | - | 957 | 947 | 72.5 | 0.68 | 17b(65) + 16b(17) |
25 | π(CCα) 10b | - | 196 | 204 | 211 | 0.52 | 12.94 | ω(NO2)(26) + 10b(21) + 17a(18) + τ(CCα)(15) + 16a(12) |
26 | π(CN) 17a | - | 172 | 158 | 158 | 44.7 | 1.37 | 10b(22) + 16b(15) + w(Cα=O)(20) + 17a(14) + 10a(10) |
27 | π(CCʹ) 10a | - | 291 | 277 | 280 | 22.35 | 1.37 | 10a(28) + w(Cα=O)(20) + 16a(15) + 10b(14) |
28 | τ(CCCC) 4 | 699 | 695 | 738 | 728 | 55 | 9.411 | 4(32) + w(Cα=O)(20) + 10b(16) |
29 | τ(CCCC) 16a | 560 | - | 574 | 575 | 27.5 | 7.58 | 16a(34) + w(OH)(12) + 10b(12) + 17a(11) |
30 | τ(CCCC) 16b | 485 | 489 | 445 | 450 | 32.5 | 4.7 | 16b(52) + 17a(16) + 10b(12) |
Vibrations of acid group | ||||||||
31 | ν(Cα=O) | 1698 | - | 1713 | 1714 | 100 | 1.72 | ν(Cα=O)(80) |
32 | ν(Cα-OH) | 1319 | 1316 | 1316 | 1313 | 90 | 23.52 | ν(Cα-OH)(29) + 12(25) + 14(22) |
33 | δ(OH) | 1425 | - | 1455 | 1459 | 95 | 5.83 | δ(OH)(61) + 19b(16) |
34 | ν(O-H) | - | - | 3627 | 3627 | 8.33 | 3.44 | ν(O-H)(100) |