What absorbs at 1684 cm⁻¹ in an FTIR spectrum?
A band near 1684 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
Răspuns rapid
A band near 1684 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.
Atribuiri posibile ale grupelor funcționale
| Grup funcțional | Fapte suport | Surse citate | Încredere maximă |
|---|---|---|---|
| Amide | 4 | 4 | 1,0 |
| Carbonyl (C=O) | 3 | 3 | 1,0 |
| Alkyl C-H | 3 | 3 | 1,0 |
| Aromatic ring | 3 | 3 | 1,0 |
| Carboxyl (COOH) | 3 | 3 | 1,0 |
| Ester | 2 | 2 | 1,0 |
| Methyl | 2 | 2 | 1,0 |
| Methacrylate | 2 | 2 | 1,0 |
| Acetate | 2 | 2 | 1,0 |
| Lipid | 1 | 1 | 1,0 |
| Methoxy (OCH3) | 1 | 1 | 1,0 |
| Fatty acid | 1 | 1 | 1,0 |
| Ketone | 1 | 1 | 1,0 |
| Hydrogen bond | 1 | 1 | 1,0 |
| Water (H2O) | 1 | 1 | 1,0 |
| Hydroxyl (O-H) | 1 | 1 | 1,0 |
| Alkene (C=C) | 1 | 0 | 1,0 |
Clasamentul reflectă dovezile acumulate din literatură, nu o singură regulă autoritară. Confirmați întotdeauna în contextul mostrei dvs.
Materiale posibile
| Material | Vârfuri suport | Grupuri suprapuse | Surse citate |
|---|---|---|---|
| Methacrylate | 1684, 873, 1725 | Alkyl C-H, Carbonyl (C=O) | 1 |
| polyurethanes | 1684, 1740, 1728 | Amide, Carbonyl (C=O), Alkyl C-H | 1 |
| lignin | 1684, 1035, 1510 | Alkyl C-H, Aromatic ring | 1 |
Materialele sunt afișate numai atunci când același grup de literatură susține această bandă și cel puțin un vârf caracteristic suplimentar.
Logica spectrului
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 1684 cm⁻¹ is usually not enough for material identification by itself.
Utilizare în condiții reale
Acest tip de interogare este comun în identificarea polimerilor, screeningul materialelor plastice necunoscute, depanarea QC, verificarea materialelor reciclate și revizuirea atribuirii vârfurilor bazată pe literatură.
Greșeli comune
- Tratarea unei benzi izolate ca dovadă a unui material fără a verifica cel puțin unul sau două vârfuri de susținere.
- Ignorând suprapunerea: mai multe grupuri funcționale pot contribui în apropierea aceluiași număr de undă.
- Omiterea validării atunci când aditivii, amestecurile, oxidarea sau contaminarea pot distorsiona spectrul.
Sfat de verificare
Când ambiguitatea rămâne, validați ipoteza prin DSC, GC-MS sau TGA, în special pentru amestecuri, probe degradate și polimeri umpluți.
Literatura din spatele acestor atribuiri
-
Hydroxyl (O-H) încredere 1,0
“J.-H.Liuetal./SpectrochimicaActaPartA61(2005)893-899 895 ∼1684cm-1 The O H stretching bands of pure water are generally for MgSO in the region of bending peak at”
Liu 等 - 2005 - Drawing out the structural information of the firs DOI: 10.1016/j.saa.2004.06.030 -
Carboxyl (COOH) încredere 1,0
“In addition, 1433.11 cm-1 Moreover, absorption of C=O obtained in 1683.86 4a the presence of the phenethyl group in was also indicated that the carbonyl group belongs to a carboxylic confirmed by the absorption band at 746.45 and acid moiet”
Rasyid 等 - 2022 - Synthesis of N-phenethyl-p-methoxycinnamamide and DOI: 10.22146/ijc.76802 -
Hydrogen bond încredere 1,0
“LLM confirmed rule peak-group candidate”
Time-dependent morphology development in segmented polyetherurea copolymers based on aromatic diisocyanates DOI: 10.1002/polb.21652 -
Carboxyl (COOH) încredere 1,0
“LLM confirmed rule peak-group candidate”
Transition Metal Oxodiperoxo Complex Modified Metal-Organic Frameworks as Catalysts for the Selective Oxidation of Cyclohexane DOI: 10.3390/ma13040829 -
Methyl încredere 1,0
“corresponding to aliphatic and aromatic -OH (3415 cm-1), aromatic ring modes (1595 cm-1 and 1140 cm-1), carbonyl group (1684 cm-1), aliphatic -CH3 (2944 cm-1) and CH2 groups (1453 cm-1), symmetric -CH3 stretching of the methoxyl groups (285”
Characterization and Evaluation of Hydrothermal Liquefaction Char from Alkali Lignin in Subcritical Temperatures DOI: 10.3390/ma14113024 -
Acetate încredere 1,0
“cm-1 The appearance of a C=O stretching vibration band at 1684 (as a "shoulder" cm-1 to the intrinsic 1673 band) in the spectra of all diltiazem-Eudragit RS 100 physical cm-1 The appearance of а C=O stretching vibration band at 1684 (as a "”
Kolev 等 - 2022 - Ammonio Methacrylate Copolymer (Type B)-Diltiazem DOI: 10.3390/polym14102125 -
Amide încredere 1,0
“We observed the primary amide III band band and amide I band were centered around ~1571 cm-1 and ~1684 cm-1, respectively, for tissues.”
Comprehensive Evaluation of PAXgene Fixation on Oral Cancer Tissues Using Routine Histology, Immunohistochemistry, and FTIR Microspectroscopy DOI: 10.3390/biom11060889 -
Alkyl C-H încredere 1,0
“f cm-1 cm-1 -C-H -C-H 2880.32 for aliphatic stretching, 1684.32 and FTIR: 3062.84 and 3028.98 for aromatic cm-1 cm-1 -N�CH-”
Manjare 等 - 2023 - Microwave-Assisted Rapid and Green Synthesis of Sc DOI: 10.1021/acsomega.2c05187
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