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FTIR Spectroscopic and Theoretical Study of the Photochemistry of Matrix-isolated Coumarin
Nihal Kuş, Susana Breda, Igor Reva, Erol Tasal, Cemil Ogretir and Rui Fausto
DOI: 10.1111/j.1751-1097.2007.00233.x
In the most recent issue of Photochemistry and Photobiology, 2007, 83(5), 1237–1253, an error in Table 2 was published.
| Approximate description† | Sym. | Calculated DFT(B3LYP)/ 6-311++G(d,p) | Calculated MP2/6-31G(d,p) | Observed spectrum Ar (10 K) | |||
|---|---|---|---|---|---|---|---|
| Freq.‡ | Int. | Freq.§ | Int. | Freq. | Int.|| | ||
| ν(C3–H) | A′ | 3099 | 0.3 | 3100 | 0.5 | – | |
| ν(C7–H) | A′ | 3088 | 3.2 | 3087 | 4.1 | 3096 | 1.0 |
| ν(C9–H) | A′ | 3079 | 11.0 | 3079 | 10.6 | 3085,3079 | 1.5 |
| ν(C8–H) | A′ | 3065 | 7.0 | 3064 | 5.5 | 3059 | 1.0 |
| ν(C10–H) | A′ | 3055 | 5.2 | 3050 | 0.9 | 3053 | 1.1 |
| ν(C4–H) | A′ | 3051 | 4.1 | 3052 | 11.0 | 3043 | 0.7 |
| ν(C=O) | A′ | 1772 | 718.0 | 1757 | 422.3 | 1776,1774,1772,1767,1762, 1759,1752,1748,1747 | 456.6 |
| ν(C3=C4) | A′ | 1633 | 65.9 | 1628 | 24.8 | 1635,1632,1631,1630 | 45.0 |
| ν(C10–C9) | A′ | 1616 | 60.7 | 1608 | 25.7 | 1617,1613,1612,1610 | 54.1 |
| ν(C8–C7) | A′ | 1568 | 39.3 | 1566 | 6.3 | 1572,1571 | 12.7 |
| δ(C–H) ph | A′ | 1489 | 5.2 | 1484 | 8.4 | 1492 | 3.2 |
| ν(C7–C6) | A′ | 1453 | 23.4 | 1445 | 31.6 | 1459,1458,1455 | 25.8 |
| δ(C–H) py | A′ | 1400 | 10.1 | 1425 | 11.6 | 1399 | 9.8 |
| ν(C5–C6)/δ(C–H) ph | A′ | 1336 | 2.7 | 1390 | 12.8 | 1329,1327 | 1.9 |
| δ(C–H) ph/ν(C5–C6) | A′ | 1273 | 20.7 | 1258 | 27.3 | 1278,1276,1275 | 13.2 |
| ν(C6–O) | A′ | 1255 | 28.6 | 1242 | 14.0 | 1263,1262,1260,1259 | 17.6 |
| ν(C4–C5) | A′ | 1225 | 13.1 | 1224 | 2.2 | 1233,1232,1228,1226,1225 | 13.8 |
| δ(C–H) py/ν(C2–C3) | A′ | 1169 | 25.6 | 1174 | 99.5 | 1202,1197,11961194,1181,1178 | 69.2 |
| δ(C–H) ph | A′ | 1156 | 0.9 | 1151 | 0.9 | 1156,1153 | 1.2 |
| δ(C–H) ph | A′ | 1118 | 20.5 | 1111 | 47.5 | 1134,1132,1129,1128,1123,1119,1118 | 32.6 |
| ν(C2–C3)/δ(C–H) py | A′ | 1075 | 99.8 | 1088 | 49.2 | 1106,1102,1098,1097 | 56.1 |
| ν(C9–C8) | A′ | 1030 | 2.2 | 1021 | 1.3 | 1031,1030 | 1.0 |
| γ(C–H) py | A′′ | 983 | 0.5 | 964 | 0.5 | 984,982 | 0.2 |
| γ(C–H) ph | A′′ | 969 | 0.2 | 917 | 0.3 | – | |
| γ(C−H) ph | A′′ | 948 | 3.2 | 903 | 0.5 | 945,944,942,940 | 3.4 |
| ν(O−C2)/δ ring ph | A′ | 922 | 28.8 | 911 | 23.5 | 929,927,926 | 19.8 |
| δ ring ph/ν(O–C2) | A′ | 875 | 43.3 | 949 | 41.5 | 888,886 | 21.0 |
| γ(C–H) ph | A′′ | 863 | 3.1 | 843 | 0.6 | 866,865,864 | 2.3 |
| γ(C–H) py | A′′ | 830 | 59.1 | 827 | 61.0 | 832,829,828,827 | 52.2 |
| ν(C10–C5) | A′ | 761 | 2.5 | 785 | 2.6 | 765,763,762,761,759,753 | 56.2 |
| γ(C–H) ph | A′′ | 761 | 46.8 | 763 | 46.0 | ||
| τ ring py¶ | A′′ | 740 | 15.9 | ||||
| δ ring ph | A′ | 731 | 2.6 | 754 | 1.7 | 726,725 | 1.1 |
| γ(C=O) | A′′ | 678 | 0.5 | 669 | 4.2 | 680 | 0.2 |
| δ ring py | A′ | 614 | 8.3 | 626 | 9.7 | 610 | 7.3 |
| τ ring py | A′′ | 538 | 0.2 | 503 | 0.0 | – | |
| δ ring py | A′ | 530 | 6.7 | 542 | 3.9 | 527,526 | 2.0 |
| δ(C=O) | A′ | 489 | 5.4 | 497 | 3.9 | 490,486(?) | 0.6 |
| τ Butterfly | A′′ | 454 | 5.2 | 435 | 1.3 | 459,452 | 4.6 |
| δ ring ph | A′ | 445 | 1.5 | 456 | 0.8 | 446 | 0.3 |
| τ ring py¶ | A′′ | 355 | 0.4 | Not investigated | |||
| τ ring ph | A′′ | 369 | 0.1 | 327 | 0.1 | ||
| δ ring py | A′ | 304 | 0.8 | 308 | 1.0 | ||
| τ ring py | A′′ | 253 | 0.5 | 243 | 0.3 | ||
| τ ring ph | A′′ | 154 | 4.6 | 154 | 4.5 | ||
| τ ring ph | A′′ | 93 | 1.4 | 93 | 1.2 | ||
- *See Table S1 for definition of symmetry coordinates and Tables S2 and S3 for PEDs calculated using the DFT and MP2 force constants and geometries, respectively. †Approximate description is known to be an oversimplification of the vibrations description, where their description in terms of a single, most significant symmetry coordinate was attempted. The detailed description is given in the PED form (Tables S2 and S3). ν, bond stretching; δ, bending; γ, rocking; τ, torsion; ph, phenyl ring; py, pyrone ring. Wherever two approximate descriptions are given, separated by a slash (/) symbol, the left one corresponds to the approximate description extracted from the PEDs calculated at the DFT(B3LYP)/6-311++G(d,p) level and the right one to that obtained based on the MP2/6-31G(d,p) calculations. ‡Theoretical positions of absorption bands were scaled by a factor 0.964 in the 4000–2500 cm−1 region; 0.982 in the 2500–1000 cm−1 region and 0.989 in the region below 1000 cm−1. §Theoretical positions of absorption bands were scaled by a factor of 0.938 in the 4000–2500 cm−1 region; 0.956 in the 2500–1000 cm−1 region and 1.014 in the region below 1000 cm−1. ||Observed intensities (Intexp) correspond to band integral absorbances (A) normalized by the theoretical intensities (Intcalc) at MP2/6-31G(d,p) level, according to the formula Intexp(i) = A(i)ΣIntcalc/ΣA, where the sums extend to all theoretical bands which have an experimentally observed counterpart. ¶In the low frequency region the torsional vibrations of the pyrone ring were predicted in a substantially different way by the DFT(B3LYP)/6-311++G(d,p) and MP2/6-31G(d,p) methods.
The corrected Table 2 is shown:
