Table 2. Experimental and Calculated Frequencies (cm–1) and Tentative Assignment of the Most Relevant Vibrational Modes for 3a–3h.
|
compound 3a |
compound 3b |
||||||
|---|---|---|---|---|---|---|---|
| assignment PED (%)a | Exp. | Calc.c |
assignment PED (%)a | Exp. | Calc.c |
||
| IRb | Freq. | Int. | IRb | Freq. | Int. | ||
| νs (C–H) (86) Ar | 3045 (vw) | 2768 | 250 | νs (C–H) (88) Ar | 3052 (vw) | 2758 | 324 |
| νas (C–H) (91) Ar | 3035 (vw) | 2759 | 267 | νas (C–H) (96) Ar | 3019 (vw) | 2719 | 145 |
| νas (CH3) (84) pyrazole | 3001 (vw) | 2678 | 175 | νas (CH3) (97) pyrazole | 2961 (vw) | 2677 | 122 |
| νas (CH3) (88) pyrazole | 2960 (vw) | 2659 | 118 | νas (CH3) (88) pyrazole | 2846 (vw) | 2658 | 80 |
| ν (C–H) (91) azomethine | 2928 (vw) | 2626 | 105 | ν (C=O) (87) pyrazole | 1643 (vs) | 1859 | 422 |
| ν (C=O) (89) pyrazole | 1643 (vs) | 1859 | 891 | ν (C=C) (83) alkene | 1607 (w) | 1776 | 24 |
| ν (C=C) (81) alkene | 1594 (m) | 1776 | 9 | ν (C=N) (84) azomethine | 1592 (w) | 1721 | 21 |
| ν (C=N) (77) azomethine | 1587 (m) | 1722 | 5 | νas (NO2) (91) | 1569 (s) | 1706 | 839 |
| ν (C=C) (69) pyrazole | 1558 (m) | 1657 | 368 | ν (C=C) (63) pyrazole | 1557 (m) | 1649 | 319 |
| δ (C–C–H) (31) ip Ar | 1415 (m) | 1509 | 282 | δ (C–C–H) (32) ip Ar | 1510 (m) | 1509 | 293 |
| ν (C–N) (53) pyrazole | 1455 (w) | 1413 | 307 | νs (NO2) (74) | 1444 (w) | 1441 | 420 |
| ν (N–N) (61) pyrazole | 1447 (w) | 1388 | 345 | ν (C–N) (52) pyrazole | 1428 (w) | 1417 | 435 |
| δ (CH3) (35) pyrazole | 1307 (m) | 1298 | 26 | ν (N–N) (52) pyrazole | 1413 (w) | 1390 | 340 |
| δ (C–C–N) (35) pyrazole | 1133 (m) | 1169 | 438 | δ (CH3) (29) pyrazole | 1077 (w) | 1077 | 77 |
| δ (N–C–H) (56) pyrazole | 1045 (w) | 1056 | 72 | δ (C–C–H) (63) pyrazole | 978 (m) | 970 | 5 |
| δ (CH3) (60) pyrazole | 1117 (s) | 1017 | 60 | ||||
| δ (C–C–H) (78) pyrazole | 858 (vw) | 963 | 85 | ||||
|
compound 3c |
compound 3d |
||||||
|---|---|---|---|---|---|---|---|
| assignment PED (%)a | Exp. | Calc.c |
assignment PED (%)a | Exp. | Calc.c |
||
| IRb | Freq. | Int. | IRb | Freq. | Int. | ||
| νs (C–H) (94) Ar | 3035 (vw) | 2769 | 245 | νs (CH3) (34) pyrazole | 3039 (vw) | 2779 | 77 |
| νas (C–H) (89) Ar | 3007 (vw) | 2763 | 259 | νs (CH3) (19) pyrazole | 2961 (vw) | 2762 | 74 |
| νs (C–H) (76) Alkene | 2960 (vw) | 2745 | 214 | νas (C–H) (63) Ar | 2926 (vw) | 2758 | 235 |
| νas (CH3) (93) pyrazole | 2681 (vw) | 2737 | 28 | νas (C–H) (53) Ar | 2892 (vw) | 2752 | 233 |
| νas (CH3) (89) pyrazole | 2812 (vw) | 2735 | 92 | νas (C–H) (90) Ar | 2853 (vw) | 2735 | 93 |
| ν (C=O) (86) pyrazole | 1643 (vs) | 1851 | 904 | νs (CH3) (29) N,N-dimethyl | 2810 (vw) | 2673 | 94 |
| ν (C=C) (78) alkene | 1614 (w) | 1772 | 102 | νas (CH3) (28) N,N-dimethyl | 2797 (vw) | 2664 | 74 |
| ν (C=N) (79) azomethine | 1594 (w) | 1737 | 274 | ν (C=O) (86) pyrazole | 1643 (s) | 1850 | 418 |
| ν (C=C) (74) pyrazole | 1579 (w) | 1686 | 606 | ν (C=N) (47) azomethine | 1600 (s) | 1737 | 139 |
| ν (C–N) (36) pyrazole | 1435 (w) | 1406 | 96 | ν (C=C) (34) pyrazole | 1564 (m) | 1647 | 533 |
| δ (CH3) (74) methoxy | 1414 (w) | 1385 | 631 | ν (C–N) (30) N,N-dimethyl | 1434 (m) | 1440 | 250 |
| ν (N–N) (19) pyrazole | 1413 (w) | 1361 | 320 | ν (C–N) (22) pyrazole | 1407 (w) | 1404 | 146 |
| δ (CH3) (80) pyrazole | 1381 (w) | 1331 | 72 | ν (N–N) (27) pyrazole | 1368 (s) | 1385 | 375 |
| δ (C=C–H) (74) azomethine | 1346 (vw) | 1294 | 139 | δs (CH3) (19) N,N-dimethyl | 1314 (w) | 1353 | 37 |
| δ (C–C–H) (48) ip Ar | 1510 (m) | 1245 | 76 | δ (CH3) (34) pyrazole | 1288 (m) | 1332 | 79 |
| δ (O–C–H) (51) methoxy | 1074 (vw) | 1069 | 1 | δ (C=C–H) (22) azomethine | 1239 (vw) | 1294 | 58 |
| δ (CH3) (52) pyrazole | 1050 (w) | 1062 | 46 | δas (CH3) (27) N,N-dimethyl | 1184 (w) | 1252 | 61 |
| δ (C–C–H)(46) oop alkene | 991 (m) | 967 | 43 | δas (CH3) (18) N,N-dimethyl | 1023 (m) | 1024 | 74 |
| δ (C–C–H) (20) oop alkene | 946 (m) | 951 | 72 | ||||
|
compound 3e |
compound 3f |
||||||
|---|---|---|---|---|---|---|---|
| assignment PED (%)a | Exp. | Calc.c |
assignment PED (%)a | Exp. | Calc.c |
||
| IRb | Freq. | Int. | IRb | Freq. | Int. | ||
| νs (C–H) (26) Ar | 3028 (vw) | 2769 | 117 | νas (CH3) (36) ketone | 3103 (vw) | 2778 | 83 |
| νas (C–H) (57) Ar | 3011 (vw) | 2758 | 186 | νs (C–H) (41) Ar | 3067 (vw) | 2768 | 229 |
| νas (C–H) (62) Ar | 2979 (vw) | 2752 | 123 | νas (C–H) (49) Ar | 3054 (vw) | 2759 | 242 |
| νas (CH3) (52) acetoxy | 2941 (vw) | 2684 | 123 | νas (C–H) (89) Ar | 3042 (vw) | 2735 | 93 |
| νas (CH3) (51) pyrazole | 2916 (vw) | 2678 | 116 | ν (C–H) (98) ketone | 3029 (vw) | 2728 | 134 |
| νas (CH3) (77) acetoxy | 2876 (vw) | 2651 | 119 | νas (CH3) (65) ketone | 2995 (vw) | 2678 | 106 |
| νs (C–H) (48) azomethine | 2828 (vw) | 2624 | 74 | νas (CH3) (56) pyrazole | 2942 (vw) | 2659 | 86 |
| ν (C=O) (88) ester | 1755 (vs) | 1860 | 421 | ν (C=O) (88) pyrazole | 1645 (vs) | 1857 | 393 |
| ν (C=O) (88) pyrazole | 1744sh (m) | 1843 | 710 | ν (C=N) (69) azomethine | 1608 (w) | 1728 | 13 |
| ν (C=N) (77) azomethine | 1655 (w) | 1722 | 12 | ν (C=C) (66) pyrazole | 1591 (m) | 1666 | 294 |
| ν (C=C) (56) pyrazole | 1640 (m) | 1652 | 383 | δ (C–C–H) (35) ip Ar | 1567 (w) | 1641 | 100 |
| δ (C–C–H) (16) ip Ar | 1594 (m) | 1509 | 308 | ν (C–N) (17) pyrazole | 1492 (m) | 1509 | 276 |
| ν (C–N) (17) pyrazole | 1509 (m) | 1418 | 257 | ν (C–N) (22) pyrazole | 1509 (w) | 1412 | 246 |
| ν (N–N) (26) pyrazole | 1483 (m) | 1389 | 271 | ν (N–N) (25) pyrazole | 1417 (m) | 1388 | 316 |
| δ (CH3) (17) pyrazole | 1467 (m) | 1368 | 131 | δ (CH3) (38) pyrazole | 1337 (m) | 1332 | 76 |
| δ (CH3) (38) pyrazole | 1368 (m) | 1330 | 75 | δ (C=C–H) (48) azomethine | 1225 (vw) | 1266 | 21 |
| δ (CH3) (38) acetoxy | 1344 (m) | 1312 | 123 | δ (CH3) (45) pyrazole | 1178 (w) | 1242 | 31 |
| δ (CH3) (17) acetoxy | 1289 (m) | 1212 | 354 | δ (CH3) (39) pyrazole | 1137 (m) | 1129 | 52 |
| δ (CH3) (28) methoxy | 1212 (m) | 1123 | 68 | δ (C=C–H) (18) alkene | 1075 (w) | 1194 | 41 |
| δ (CH3) (36) methoxy | 1125 (s) | 1030 | 64 | δ (CH3) (29) pyrazole | 942 (m) | 1057 | 52 |
| δ (C–C–H)(28) oop alkene | 1032 (s) | 959 | 82 | δ (CH3) (29) pyrazole | 926 (w) | 1018 | 57 |
| ν (C–O) (37) ester | 993 (vs) | 940 | 115 | ν (C–Br) (20) | 627 (w) | 614 | 60 |
|
compound 3g |
compound 3h |
||||||
|---|---|---|---|---|---|---|---|
| assignment PED (%)a | Exp. | Calc.c |
assignment PED (%)a | Exp. | Calc.c |
||
| IRb | Freq. | Int. | IRb | Freq. | Int. | ||
| νs (CH3) (34) pyrazole | 3145 (vw) | 2779 | 82 | νs (C–H) (27) Ar | 3117 (vw) | 2768 | 117 |
| νs (C–H) (50) Ar | 3099 (vw) | 2768 | 156 | νas (C–H) (56) Ar | 3100 (vw) | 2756 | 192 |
| νas (C–H) (37) Ar | 3067 (vw) | 2761 | 239 | νas (C–H) (55) Ar | 3071 (vw) | 2749 | 210 |
| νas (C–H) (39) Ar | 3052 (vw) | 2753 | 111 | νas (C–H) (80) Ar | 3031 (vw) | 2724 | 137 |
| νas (C–H) (31) ketone | 3040 (vw) | 2748 | 76 | νas (C–H) (76) Ar | 3022 (vw) | 2722 | 113 |
| νas (C–H) (89) Ar | 3026 (vw) | 2735 | 92 | νas (CH3) (42) pyrazole | 2997 (vw) | 2677 | 84 |
| νas (CH3) (58) alkene | 2984 (vw) | 2691 | 84 | νas (CH3) (47) pyrazole | 2975 (vw) | 2657 | 84 |
| νas (CH3) (65) pyrazole | 2959 (vw) | 2679 | 77 | ν (C–H) (49) alkene | 2928 (vw) | 2624 | 76 |
| νas (CH3) (55) alkene | 2943 (vw) | 2675 | 97 | ν (C=O) (81) pyrazole | 1646 (vs) | 1861 | 417 |
| νas (CH3) pyrazole | 2919 (vw) | 2661 | 79 | ν (C=N) (78) azomethine | 1612sh (w) | 1718 | 54 |
| ν (C=O) (86) pyrazole | 1641 (vs) | 1850 | 427 | ν (NO2) (48) | 1594 (s) | 1714 | 586 |
| ν (C=N) (74) azomethine | 1618sh (w) | 1758 | 19 | ν (C=C) (41) pyrazole | 1568 (s) | 1645 | 158 |
| ν (C=C) (58) pyrazole | 1588 (s) | 1688 | 194 | δ (C–C–H) (25) ip Ar | 1549 (m) | 1634 | 626 |
| δ (C–C–H) (35) ip Ar | 1571 (w) | 1641 | 88 | ν (C–N) (16) pyrazole | 1511 (s) | 1508 | 278 |
| δ (C–C–H) (16) ip Ar | 1494 (m) | 1527 | 40 | ν (NO2) (42) | 1433 (m) | 1443 | 725 |
| δ (C–C–H) (17) ip Ar | 1481 (m) | 1510 | 272 | ν (N–N) (23) pyrazole | 1420 (w) | 1392 | 286 |
| ν (C–N) (24) pyrazole | 1418 (m) | 1409 | 103 | ν (C–N) (14) azomethine | 1410 (w) | 1378 | 170 |
| ν (N–N) (27) pyrazole | 1387 (w) | 1387 | 290 | δ (CH3) (19) pyrazole | 1377 (w) | 1353 | 66 |
| δ (C=C–H) (23) alkene | 1371 (w) | 1370 | 99 | δ (CH3) (17) pyrazole | 1335 (w) | 1334 | 92 |
| δ (CH3) (23) alkene | 1313sh (w) | 1342 | 90 | δ (CH3) (37) pyrazole | 1250 (w) | 1217 | 75 |
| δ (CH3) (18) alkene | 1302 (m) | 1336 | 85 | δ (C=C–H) (44) alkene | 972 (m) | 958 | 92 |
| δ (C=C–H) (76) azomethine | 1191 (vw) | 1282 | 13 | δ (NO2) (31) | 871 (m) | 808 | 92 |
| δ (CH3) (51) pyrazole | 1176 (w) | 1244 | 43 | δ (NO2) (37) oop | 826 (m) | 764 | 109 |
| δ (CH3) (39) pyrazole | 1154 (w) | 1229 | 52 | δ (NO2) (39) ip | 534 (w) | 527 | 2 |
a
ν, δ, y, and γ represent stretching, in-plane deformation (ip), and out-of-plane deformation (op) vibrational modes, respectively. In parentheses, potential energy distribution (PED) analysis.
b
vs, very strong; s, strong; m, medium; w, weak; vw, very weak; and sh, shoulder.
c
Calculated infrared frequencies (cm–1) and intensities (km mol–1) in parentheses (B3LYP/6-311++G(d,p).