| | Experimental Raman values (cm−1) | SERS values (cm−1) | Vibrational assignment [34, 35] |
| | 1680 | 1662 | sciss NH2, υ (C-N), υ (C-C)/ring stretch | | 1610 | 1626 | υ (N-C), υ (C-C), δ (H–C–H), δ (C–N–H) | | 1597 | 1589 | sciss NH2, υ R6 (C=C) | | | 1518 | δ (C-H ring) + υ (C-C) | | 1485 | 1463 | υ (N-C), δ (C-H), sciss NH2 | | 1420 | 1402 | υ (C-N), δ (C-H), υ (C–C) + δ (CH3) | | 1373 | 1372 | δ (C-H, N-H), υ (C-N) and δ (C–O–H) + δ (C-O-H) + (CH2) twist | | 1335 | 1332 | δ (C2-H, C8-H, N9-H), υ (C6-N1, C8-N9, N3-C4) | | 1335 | | δ (C–N–H) + δ (C–C–H) + δ (C–H) i.p., ring τ + δ (H-C-O), υ (C-N) | | 1308 | | υ (C-N), υ (C-C) | | 1250 | 1245 | δ (C-H, N-H) i.p., υ (N7-C8), δ (C-O-H)/(C-C-H) | | 1234 | | rock NH2, υ (C-N, N-C) | | 1165 | 1171 | δ (C-H, N-H), υ (C-N, N-C) | | 1128 | 1120 | υ (C8-N9), δ (N9-H, C8-H), | | 1025 | 1033 | rock NH2, ring stretch, τ (H–C–O–H) + υ (C-C-O) | | | 982 | wag (C-H) o.p., δ (N–H) o.p. + δ (C–C), υ (C-O) | | 942 | 962, 942 sh. | def R5 | | 893 | 882 | def R6, R5 υ (C-N) | | 773 | 800 | def R6 (wag C-C-C), wag (C-H) o.p. | | 722 | 732 | Ring breath whole molecule (distorted) | | 622 | 623 | def R6 and R5, τ (C–C–C–H) + stretch quadrant (C–C–C–N), τ (C-C-C-C) | | 560 | 591 | wag (C2-H, N9-H) o.p. | | 533 | 532 | def R6—i.p./o.p. | | 533 | 532 | wag (N-H), def R6, R5—i.p./o.p., δ (OH–C–C–CH3) + τ (H–C–N–H), υ (C-C) + υ (C-O) | | 474 | 455 | wag (N-H), τ (NH2) o.p. | | 375 | 377 | def R6, R5 wag (N-C-N-C, C-N-C-N), wag (C-N) o.p. |
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