What absorbs at 1291 cm⁻¹ in an FTIR spectrum?
A band near 1291 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 1291 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) | 5 | 5 | 1,0 |
| Methacrylate | 5 | 5 | 1,0 |
| C-O single bond | 5 | 5 | 1,0 |
| Acetate | 5 | 5 | 1,0 |
| Amide | 4 | 3 | 1,0 |
| Hydroxyl (O-H) | 2 | 2 | 1,0 |
| Secondary amine | 2 | 2 | 1,0 |
| C n single bond | 2 | 2 | 1,0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1,0 |
| Alkene (C=C) | 1 | 1 | 1,0 |
| Carboxyl (COOH) | 1 | 1 | 1,0 |
| Fluorine (C-F) | 1 | 1 | 1,0 |
| Alkyl C-H | 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 |
|---|---|---|---|
| PVP | 1291, 2983, 1648 | Methacrylate, Acetate | 1 |
| polyaniline | 1291, 1565, 1570 | Methacrylate, Acetate | 1 |
| copolymer | 1291, 2921, 1540 | Methacrylate, Acetate | 1 |
| PVDF | 1291, 1160, 840 | Methacrylate, Acetate | 1 |
| Fe2O3 | 1291, 1130, 1631 | Methacrylate, Acetate | 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 1291 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
“Additional bands corresponding to C-O-H bending appeared at 1291 cm-1.”
Can 等 - 2023 - Choline Chloride-Based Deep Eutectic Solvent-Treat DOI: 10.3390/f14030569 -
Amide confiança 1,0
“Peak at 1291 which also confirms the self-doped structure of the copolycm-1 indicate C N stretching and C H and at 3214 mer as proposed in reaction 1.”
Dey Sadhu 等 - 2020 - Preparation and characterization of polyanilinea DOI: 10.1002/pc.25738 -
Amide confiança 1,0
“The peak at 1291 was due to C-N stretching vibration and this confirmed the presence of the amine group in pure in the memcm-1 brane matrix.”
Experimental and DFT studies on the structural and optical properties of chitosan/polyvinyl pyrrolidone/ZnS nanocomposites DOI: 10.1007/s00289-023-04700-0 -
Acetate confiança 1,0
“In addition, a of thermogram which had two melting shifting of the C-O vibration of BA at 1291.40 points at 157.0 and 188.8 °C, respectively, cm-1 to 1379.16 was proof of deprotonation in corresponding to the DES and SA melting”
Ainurofiq 等 - 2018 - Synthesis, characterization, and stability study o DOI: 10.1080/10837450 -
Acetate confiança 1,0
“In BA, the neutral carboxylic group (-COOH) had a strong carbonyl (C=O) with stretching at a peak of 1686.82 cm-1 and a weak carbonyl (C-O) stretching at 1291.40 cm-1.”
A Novel Desloratadine-Benzoic Acid Co-Amorphous Solid: Preparation, Characterization, and Stability Evaluation DOI: 10.3390/pharmaceutics10030085 -
Fluorine (C-F) confiança 1,0
“O nline 1300 1300 CF symmetric stretching and rocking 1291 [19] α PVDF 2 L ibrary”
Chipara 等 - 2020 - Spectroscopic investigations on PVDF-Fe2O3 nanocom DOI: 10.1002/app.48907 -
Acetate confiança 1,0
“The peaks at 1585-1500 cm-1 resulted from the C=C stretching vibrations of the aromatic ring cm-1 C=C at 1585-1500 resulted from the stretching vibrations of the aromatic ring while the peak at while the peak at 1291 cm-1 can be assigned to”
Kowalczuk - 2020 - FTIR Characterization of the Development of Antimi DOI: 10.3390/coatings10090818 -
Alkene (C=C) confiança 1,0
“The porphyrin peaks at 1494 cm-1 and 1291 cm-1 due to their C=C and C-N stretching can also be seen in the GO@AuNRs-TMePyP spectrum.”
Graphene Oxide-Gold Nanorods Nanocomposite-Porphyrin Conjugate as Promising Tool for Cancer Phototherapy Performance DOI: 10.3390/ph14121295
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