TRANSMITTANCE1% HIT-NO-1058 SCORE= ( ) SDBS-NO=1021 IR-NIDA-06138 : CCL4 SOLUTION 3′-NITROACETOPHENONE C
H
NO
100 50 0 4000 3000 2000 1500 1000 500 WAVENUMBER(-1) 3083 84 1702 14 1660 84 1616 60 1581 84 1538 20 1478 62 1434 64 1353 8 1318 66 1291 30 1280 62 1253 4 1162 77 1113 63 1074 72 1022 86 970 81 955 74 936 84 920 84 904 70 884 70 873 79 678 26 665 50 597 44 689 68 O
N C-CH
O
The Correct Answer and Explanation is:
The infrared (IR) spectrum of 3′-Nitroacetophenone provides insight into the molecular structure by identifying specific functional groups based on their characteristic absorption frequencies. The transmittance values indicate how much infrared light is absorbed by the sample at different wavenumbers.
The strong peak observed at approximately 1702 cm^-1 is attributed to the C=O stretching vibration of the acetophenone group. Carbonyl groups typically exhibit intense absorptions in this region, confirming the presence of the ketone functional group. Peaks near 1616 cm^-1 and 1581 cm^-1 correspond to C=C stretching vibrations within the aromatic benzene ring. These absorptions are characteristic of conjugated systems, where electron delocalization influences vibrational frequencies.
The peak at 1353 cm^-1 and additional peaks around 1291 cm^-1 and 1162 cm^-1 are associated with the asymmetric and symmetric stretching vibrations of the nitro (-NO2) group. Nitro compounds typically show strong absorptions in the range of 1300-1500 cm^-1 due to the influence of both N=O bonds. Further confirmation comes from peaks at 955 cm^-1 and 936 cm^-1, which are often linked to aromatic nitro-substituted compounds.
The absorption observed at 3083 cm^-1 suggests C-H stretching vibrations in the aromatic system. Typically, aromatic hydrocarbons have stretching frequencies slightly above 3000 cm^-1. The peak at 678 cm^-1 indicates out-of-plane bending vibrations of the benzene ring. Such deformations are significant for determining substitution patterns and ring interactions.
In summary, the IR spectrum confirms the presence of an acetophenone ketone, a conjugated aromatic system, and a nitro group. These findings are consistent with the expected structure of 3′-Nitroacetophenone and help in characterizing its molecular vibrations with precision.
