What absorbs at 1139 cm⁻¹ in an FTIR spectrum?
A band near 1139 cm⁻¹ can point to several functional groups. Below are the most likely assignments, ranked by how much published evidence supports each — every one traceable to literature (DOI) and cross-validated against our 130,000+ reference spectra and knowledge graph.
Backed by 8 cited sources
Resposta rápida
A band near 1139 cm⁻¹ is usually interpreted by checking which functional groups repeatedly co-occur there in the literature, then confirming at least one or two additional peaks in the same sample. This page ranks those assignments by accumulated evidence rather than by a single fixed textbook rule.
Possíveis atribuições de grupos funcionais
| Grupo funcional | Fatos de suporte | Fontes citadas | Maior confiança |
|---|---|---|---|
| Methoxy (OCH3) | 4 | 4 | 1,0 |
| Methacrylate | 4 | 4 | 1,0 |
| C-O single bond | 4 | 4 | 1,0 |
| Acetate | 4 | 4 | 1,0 |
| Alkyl C-H | 3 | 3 | 1,0 |
| Amide | 1 | 1 | 1,0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1,0 |
| Silicon (Si) | 1 | 1 | 1,0 |
| Ester | 1 | 1 | 1,0 |
| Carbohydrate | 1 | 1 | 1,0 |
| C c single bond | 1 | 1 | 1,0 |
| N n bond | 1 | 1 | 0,9 |
A classificação reflete a evidência acumulada da literatura, não uma única regra autoritária. Sempre confirme com o contexto da sua amostra.
Materiais possíveis
| Material | Picos de suporte | Grupos sobrepostos | Fontes citadas |
|---|---|---|---|
| PMMA | 1139, 1722, 1383 | Methacrylate, Acetate, Methoxy (OCH3) | 1 |
| ZnO nanoparticles | 1139, 1219, 1726 | Methacrylate, Acetate, C-O single bond | 1 |
Os materiais são mostrados apenas quando o mesmo conjunto de literatura suporta esta banda e pelo menos um pico característico adicional.
Lógica do espectro
This band becomes meaningful only when read with its neighboring peaks. In practice, analysts first look at the assignments above, then check whether the same sample also shows other peaks expected for the same structural motif. A lone band near 1139 cm⁻¹ is usually not enough for material identification by itself.
Uso no mundo real
Este tipo de consulta é comum em identificação de polímeros, triagem de plásticos desconhecidos, solução de problemas de CQ, verificação de materiais reciclados e revisão de atribuição de picos apoiada pela literatura.
Erros comuns
- Tratar uma banda isolada como prova de um material sem verificar pelo menos um ou dois picos de suporte.
- Ignorando sobreposição: vários grupos funcionais podem contribuir próximo ao mesmo número de onda.
- Ignorar a validação quando aditivos, misturas, oxidação ou contaminação podem distorcer o espectro.
Conselho de verificação
Quando a ambiguidade persistir, valide a hipótese com DSC, GC-MS ou TGA, especialmente para misturas, amostras degradadas e polímeros carregados.
Literatura por trás destas atribuições
-
Acetate confiança 1,0
“The membrane-vehicle numbers as the proportion of water in the cosolvent increased coefficient partition (K) calculated using eq 4: C-O (Figure 1c) as did the stretching motion of PG at 1139”
Benaouda 等 - 2012 - Discriminating the Molecular Identity and Function DOI: 10.1021/mp300127f -
C c single bond confiança 1,0
“Meanwhile, the peaks at around 1139 and cm-1 726 corresponded to C-C-O asymmetric stretching and C-O symmetric stretching, cm-1.”
Can 等 - 2023 - Choline Chloride-Based Deep Eutectic Solvent-Treat DOI: 10.3390/f14030569 -
Carbohydrate confiança 1,0
“Zoomed in fingerprint region showing carbohydrate specific peaks at carbohydrates (1200 cm-1, cm-1, cm-1 1139cm-1.”
Dhaulaniya 等 - 2020 - Development of an FTIR based chemometric model for DOI: 10.1080/19440049.2020.1718774 -
Acetate confiança 1,0
“(Figure 2B), which can be assigned to the C=O stretching in aliphatic and aromatic ester 1725 cm-1 (Figure 2B), which can be assigned to the C=O stretching in aliphatic and cm-1 groups, the peak at 1164 (Figure 2C), corresponding to the C-O”
Cutinase-Catalyzed Polyester-Polyurethane Degradation: Elucidation of the Hydrolysis Mechanism DOI: 10.3390/polym14030411 -
Alkyl C-H confiança 1,0
“The 3 cm-1, cm-1 other bands were observed at 1139 and 990 attributed to the -CH twisting.”
Carrier mechanism of ZnO nanoparticles-embedded PMMA nanocomposite organic bistable memory device DOI: 10.1016/j.solidstatesciences.2019.106046 -
Alkyl C-H confiança 1,0
“1113cm-1 and1149cm-1 areherebyassignedto1139cm-1 According to DFT calculations, there are 14 C-H stretchand 1164cm-1 ing vibrations in different combinations between 3000 and , respectively, according to Table 1 and relative PED”
Ullah 等 - 2016 - Fourier Transform Infrared Spectroscopy of Bisphe DOI: 10.1155/2016/2073613 -
Silicon (Si) confiança 1,0
“cm-1 1200-400 The peaks at 1139.24 and 1095.99 are assigned to stretching cm-1 cm-1 vibration of Si-O, the peaks at 1031.25 and 1008.16 are assigned to stretching cm-1 cm-1 vibration of Si(Al)-O, the peaks at 787.56 and 761.71 are assigned”
Effects and Mechanism of Fe3+ on Flotation Separation of Feldspar and Epidote with Sodium Oleate at Natural pH DOI: 10.3390/separations9050110 -
Amide confiança 1,0
“When comparing in cellulose can be intensity patterns at cm(cid:3)1, 'Days 8-11' with alterations in the protein regions manifests 1054 which displays a reduction over time, and cm(cid:3)1 across all three approaches with the amide III peak”
Application of vibrational spectroscopy techniques to non-destructively monitor plant health and development DOI: 10.1039/c5ay00377f
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