What absorbs at 1187 cm⁻¹ in an FTIR spectrum?
A band near 1187 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
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Methacrylate | 6 | 6 | 1.0 |
| Acetate | 6 | 6 | 1.0 |
| Methoxy (OCH3) | 5 | 5 | 1.0 |
| C-O single bond | 5 | 5 | 1.0 |
| Secondary amine | 3 | 3 | 1.0 |
| Amide | 3 | 3 | 1.0 |
| C n single bond | 2 | 2 | 1.0 |
| N h | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
N h confidence 1.0
“that can be assigned to the NH Their observation of the absence of proton of E showed a band at 1187 bending vibration of a strongly hydrogen-bonded His and a release in the presence of o-phenanthroline, concomitant with cm-1 cm-1 band at 1”
Kimura 等 - 2020 - Protonation State of a Key Histidine Ligand in the DOI: 10.1021/acs.biochem.0c00810 -
Acetate confidence 1.0
“cm-1, cm-1), 2662 which characterize cyclic dimer, in-plane COH (1400 the CO bending vibrations cm-1) cm-1, (1714 and feature at 1700 which also characterizes the cyclic dimer, the COH bending cm-1 cm-1), (1400) and C-O stretching vibration”
Kondratenko 等 - 2020 - Thioglycolic Acid FTIR Spectra on Ag2S Quantum Dot DOI: 10.3390/ma13040909 -
Ester confidence 1.0
“cm-1 (1) EPMC due to the absorption at 1707 of the In this step, two amine compounds were used, namely cm-1 carbonyl ester strengthened by the band at 1186.86 phenethylamine and morpholine, to produce N-”
Rasyid 等 - 2022 - Synthesis of N-phenethyl-p-methoxycinnamamide and DOI: 10.22146/ijc.76802 -
Ester confidence 1.0
“and bands located between 1187 and 1277/cm that represented ester C=O vibrations.”
Biodegradation of P(3HB-co-4HB) powder by Pseudomonas mendocina for preparation low-molecular-mass P(3HB-co-4HB) DOI: 10.1007/s13205-017-0824-4 -
Acetate confidence 1.0
“The peaks at 1187 and 980 are 2 3 respectively attributed to the asymmetric stretching of C-O-C and the deformation of C=CH [43,44],”
Hosseini 等 - 2017 - Polymethacrylate Coated Electrospun PHB Fibers as DOI: 10.3390/s17102292 -
Amide confidence 1.0
“The -C-N band at wavenumbers 1187 and”
Preparation and Characterization of Indomethacin Supramolecular Systems with -Cyclodextrin in Order to Estimate Photostability Improvement DOI: 10.3390/molecules26247436 -
Siloxane (Si-O-Si) confidence 1.0
“Moreover, in the case of silane- -1 cm-1 samples, a peak at 1187 occurred and was attributed to the presence of siloxane”
APTES-Modified Nanocellulose as the Formaldehyde Scavenger for UF Adhesive-Bonded Particleboard and Strawboard DOI: 10.3390/polym14225037 -
Acetate confidence 1.0
“C-N, C-C and C-O stretching 1187 a 1015 A menu plot molecular graph, the electrostatic”
Rangel-Vazquez 等 - 2014 - Spectroscopy Analyses of PolyurethanePolyaniline DOI: 10.1590/0104-1428.1496
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