What absorbs at 1599 cm⁻¹ in an FTIR spectrum?
A band near 1599 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
Quick answer
A band near 1599 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.
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Aromatic ring | 10 | 10 | 1.0 |
| Ring structure | 8 | 8 | 1.0 |
| Alkene (C=C) | 6 | 6 | 1.0 |
| N h | 6 | 6 | 1.0 |
| Alkyl C-H | 4 | 4 | 1.0 |
| Carboxyl (COOH) | 4 | 4 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| C c single bond | 3 | 3 | 1.0 |
| Methacrylate | 3 | 3 | 1.0 |
| Carbonyl (C=O) | 3 | 3 | 1.0 |
| Acetate | 3 | 3 | 1.0 |
| Secondary amine | 3 | 3 | 1.0 |
| Ketone | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Amide | 2 | 2 | 1.0 |
| Amine primary | 2 | 2 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| C=n | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Urethane | 1 | 1 | 1.0 |
| Phenolic | 1 | 1 | 0.7 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| polyurethane | 1599, 2270, 1700 | N h | 2 |
| methylene blue | 1599, 1745, 1739 | N h | 1 |
Materials are shown only when the same literature pool supports this band and at least one additional characteristic peak.
Spectrum logic
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 1599 cm⁻¹ is usually not enough for material identification by itself.
Real-world usage
This type of query is common in polymer identification, unknown plastic screening, QC troubleshooting, recycled-material verification, and literature-backed peak assignment review.
Common mistakes
- Treating one isolated band as proof of a material without checking at least one or two supporting peaks.
- Ignoring overlap: multiple functional groups can contribute near the same wavenumber.
- Skipping validation when additives, blends, oxidation, or contamination may distort the spectrum.
Verification advice
When ambiguity remains, validate the hypothesis with DSC, GC-MS, or TGA, especially for blends, degraded samples, and filled polymers.
Literature behind these assignments
-
Hydroxyl (O-H) confidence 1.0
“By FTIR analysis, the characteristic peak was obtained at Haemolysis 1598.99cm-1 confirmed flavonoids the presence of functional groups associated to and other 1581.63 and phenolic groupsrespectively.Inbark extract,81%ofDPPHinhibition wasob”
Deepika 等 - 2017 - Photocatalytic degradation of synthetic food dye, DOI: 10.1016/j.jphotobiol.2017.10.015 -
Urethane confidence 1.0
“cm-1 is no such extra peak due to the presence of cholesterol corresponding to the carvery strong peak at 1729 in the ChLCPs as all the specific absorptions are possible bonyl group of the urethane linkage, peaks at 1599, 1536 October cm-1”
Jana 等 - 2009 - Molecular Orientation of Polyurethane Based Liquid DOI: 10.1080/10601320903158719 -
C c single bond confidence 1.0
“cm-1 Telmisartan 3059 (aromatic C H stretching) Complex (aromatic C H stretching) 3058 cm-1 2957 (aliphatic C H stretching) cm-1 cm-1 1699 (COOH stretching) 1652 (H O H bending) cm-1 cm-1 1599 (C C aromatic band and stretching) 1014 (C O C”
Telmisartan complex augments solubility, dissolution and drug delivery in prostate cancer cells DOI: 10.1016/j.carbpol.2013.09.077 -
confidence 1.0
“3 Effect of pH (A) and temperature (B) on the decolorization of MB by strain Acinetobacter pittii cm-1, the MB was reported at 2350 while the absorption corresponding to the H-N-H bending cm-1.Thesepeaks werealsosignificantly reducedin thes”
Biodegradation of Methylene Blue as an Evidence of Synthetic Dyes Mineralization during Textile Effluent Biotreatment by Acinetobacter pittii DOI: 10.1007/s40710-020-00443-6 -
Alkene (C=C) confidence 1.0
“LLM confirmed rule peak-group candidate”
EXPRESS: Vibrational Spectroscopic Characterization and Coherent Anti-Stokes Raman Spectroscopy (CARS) Imaging of Artepillin C DOI: 10.1177/0003702820904456 -
confidence 1.0
“The peak correspondent with the asymmetric bending mode of protonated amine [δ as(NH )] as(COO-) cm-1.44 overlaps with the ν peak at 1599 The deprotonated amine peak associated with 3+ cm-1 decreases.44 the scissor motion at 1557 [ν sc(NH 2”
pH-Dependent Adsorption of α-Amino Acids, Lysine, Glutamic Acid, Serine and Glycine, on TiO2 Nanoparticle Surfaces DOI: 10.1016/j.jcis.2019.06.086 -
Alkene (C=C) confidence 1.0
“The major band at 2918 cm-1 and 2850 cm-1 was stretching vibration cm-1 vibration of CH 2, the 1599 peak corresponded to C=C phenyl ring skeleton vibration of CH2, the 1599 cm-1 peak corresponded to C=C phenyl ring skeleton vibration and C=”
Thermal Degradation Characteristics of Styrene-Butadiene-Styrene Copolymer Asphalt Binder Filled with an Inorganic Flame-Retarding Agent DOI: 10.3390/polym14183761 -
Aromatic ring confidence 1.0
“The use of aromatic isocyanates as precursors can be deduced from the cm-1, ν(C=C) distinct absorption, at 1599 due to in the benzene ring, together with the”
Preserving the Ephemeral: A Micro-Invasive Study on a Set of Polyurethane Scenic Objects from the 1960s and 1970s DOI: 10.3390/polym15092111
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