What absorbs at 1743 cm⁻¹ in an FTIR spectrum?
A band near 1743 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 |
|---|---|---|---|
| Carbonyl (C=O) | 15 | 14 | 1.0 |
| Ester | 6 | 6 | 0.9 |
| Carboxyl (COOH) | 1 | 1 | 0.9 |
| N h | 1 | 1 | 0.8 |
| Lipid | 1 | 1 | 0.8 |
| Phospholipid | 1 | 1 | 0.7 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
Carbonyl (C=O) confidence 1.0
“Represented C=O stretching vibration.”
Ouyang 等 - 2012 - Adsorption of Cu (II) from aqueous single metal so DOI: 10.4028/www.scientific.net/AMR.535-537.1601 -
Carbonyl (C=O) confidence 1.0
“Explicit assignment: 'absorption peak at wavenumber 1743 cm-1 indicating the presence of C=O bond of the PLA'”
Triwulandari 等 - 2019 - Effect of lignin on mechanical, biodegradability, DOI: 10.1080/14658011.2018.1562746 -
confidence 0.9
“Peak at 1743 cm-1 assigned to protonation of Glu 278.”
Gorbikova 等 - 2007 - Time-resolved ATR-FTIR spectroscopy of the oxygen DOI: 10.1021/bi701614w -
Carbonyl (C=O) confidence 0.9
“Carbonyl absorption of PMMA.”
Kumar 和 Sidhu - 2013 - Synthesis and Characterization of PMMA-ZrO2 Nanoco DOI: 10.1063/1.4810163 -
Carbonyl (C=O) confidence 0.9
“Strong and sharp absorption peak at 1743 cm-1 assigned to C=O stretching vibration.”
Maulidna 等 - 2020 - Microencapsulation of ginger-based essential oil ( DOI: 10.1016/j.csite.2020.100606 -
Ester confidence 0.9
“Peak at 1743 cm-1 assigned to bond between fatty acids and glycerol.”
Yu 等 - 2021 - Adipose tissue estimates the postmortem interval b DOI: 10.1016/j.microc.2021.105977 -
Carbonyl (C=O) confidence 0.9
“Band at 1743 cm-1 associated with carbonyl stretching of carboxylic acids.”
Aguilar-Bolados 等 - 2020 - SEBS-Grafted Itaconic Acid as Compatibilizer for E DOI: 10.3390/polym12030643 -
Carbonyl (C=O) confidence 0.9
“Explicit assignment in text.”
Ang 等 - 2021 - Modifying Cellulose Acetate Mixed-Matrix Membranes DOI: 10.3390/membranes11020080
Have a spectrum with this band?
Upload your FTIR spectrum and get a full interpretation report — peak assignments with literature citations, library matches, and a confidence-rated evidence chain — in seconds.
Interpret my spectrum