Table 1. Infrared, Raman, SERS and calculated DFT vibrational frequencies (cm−1) of MTZ.
Observed |
Calculated |
Assignments with Corresponding potential energy distributions (PEDs) (%) | ||||
---|---|---|---|---|---|---|
IR | Raman (Solid) | Raman (Solution) | SERS | MTZ | MTZ-Ag | |
3159 w | 3161 w | 3166 m | 3162 | 3166 | 97% ν (C7-H) | |
3104 w | 3105 w | 3106 vw | 3142 | 3147 | 98% ν (C6-H) | |
3012 w | 3022 | 3021 | 96% ν (C5-H11) | |||
2999 | 2995 | 100% ν (C5-H12) | ||||
2949 vw | 2950 m | 2960 m | 2945 m | 2936 | 2932 | 96% ν (C5-H13) |
1578 vs | 1579 s | 1580 m | 1567 w | 1588 | 1581 | 63% ν (C6 = C7), 10% δ (N3-H) bend |
1538 vw | 1522 vs | 1509 | 1496 | 24% ν (N2-C4), 15% ν (C-C), 38% δ (H11-C-H12) bend | ||
1473 | 1467 | 23% ν (S-C4), 14% ν (C4-N) bend, 10% δ (N3-H) bend, | ||||
1479 vw | 1480 vs | 1466 | 1457 | 72% δ CHMe scissoring | ||
1462 s | 1463 vs | 1460 vw | 1452 s | 1459 | 1452 | 23% ν (S-C4), 14% ν (N3-C4), 12% δ (C-H) bend, |
1403 m | 1410 m | 1410 vw | 1408 w | 1415 | 1411 | 14% ν (N2-C4), 14% ν (N3-C6), 13% ν (S-C4), 30%δ (C -H) bend |
1339 vs | 1342 s | 1345 s | 1359 vs | 1315 | 1328 | 32% ν (N2-C4), 11% δ ring bend, 19% δ C6-N3-H bend |
1274 s | 1278 m | 1281 m | 1320 s | 1285 | 1309 | 15% ν (N2-C5), 19% δ N3-H (C6-H) bend, 14% δ ring breathing |
1248 m | 1252 vs | 1255 vw | 1277 vw | 1212 | 1237 | 51% ν (N3-C4), 18% δ N3-H (C6-H) bend, 13% δ (C7-H) bend |
1152 vs | 1156 vw | 1153 m | 1141 m | 1159 | 1150 | 16% ν (N3-C6), 16% ν (S-C4), 15% δ (H11-C-H12) rock, |
1086 vw | 1092 m | 1088 vw | 1090 m | 1089 | 1091 | 46% ν (N3-C6), 14%δ (N3-H) bend, 21% δ (C7-H) bend |
1014 s | 1016 m | 1017 vw | 1037 m | 1013 | 1022 | 15% ring CH bend, 13% δ CHMe bend, 41% δ ring bend |
913 m | 915 vs | 916 s | 937 w | 913 | 923 | 12% ν (N2-C4), 12% δ N3-H (C6-H) bend, 62% δ ring bend |
818 w | 810 vw | 830 vw | 806 | 818 | 89% γ (H-C6-C7-H) twist | |
673 vs | 679 vw | 684 vs | 687 w | 685 | 699 | 25% δ (C7-N2-C5) bend, 15% δ (C4-N2-C5) bend |
643 vw | 670 vw | 650 | 667 | 47% ring CH bend, 39% γ (N3-C4-N2) | ||
599 vw | 600 vw | 602 vw | 619 m | 603 | 623 | 78% γ CN ring bend. |
527 vs | 525 m | 522 w | 498 s | 534 | 520 | 53% δ (S-C4-N3) bend, 25% δ (S-C4-N2), |
493 vw | 503 | 569 | 84% γ (N3- C6-C7) | |||
411 s | 410 s | 410 m | 427 m | 411 | 421 | 71% δ (S-C4-N2) |
264 m | 260 m | 279 w | 238 | 251 | 85% γ (C4-S) wag | |
208 vw | 209 vw | 207 | 220 | 76% γ ring |
Values are in cm−1; ν, stretch; γ, bend; δ, symmetric. vs. very strong; s, strong; m, medium; w, weak; vw, very weak.