What absorbs at 3745 cm⁻¹ in an FTIR spectrum?
A band near 3745 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 5 cited sources
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Hydroxyl (O-H) | 4 | 4 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
Hydroxyl (O-H) confidence 1.0
“The FTIR spectrum of cm-1 band is due to residual hydroxyls absorbing about 3505 activated AlBEA sample exhibits IR bands at 3782, 3745, 3740 cm-1”
Penkova 等 - 2007 - Effect of the preparation method on the state of n DOI: 10.1021/jp071927p -
Alkyl C-H confidence 1.0
“---------- 4694, 4530 2 stretching compounds.29 ractions occur between The electrostatic potential is the energy of the interaction of a point positive charge (an electrophile) CH stretching (ring) 3745”
Delgadillo-Armendariz 等 - 2014 - INTERACTIONS OF CHITOSANGENIPIN HYDROGELS DURING DOI: 10.5935/0100-4042.20140243 -
Hydroxyl (O-H) confidence 1.0
“For cm-1 SBA-15-ex, the sharp band at 3745 could be attributed to the vibration of isolated hydroxyl group Materials 2013, 6 987”
Grafting of Amines on Ethanol-Extracted SBA-15 for CO2 Adsorption DOI: 10.3390/ma6030981 -
Hydroxyl (O-H) confidence 1.0
“3600 These bands are assigned to the O-H stretching 3745 1.8 Si-OH 12”
Miletto 等 - 2017 - Mesoporous Silica Scaffolds as Precursor to Drive DOI: 10.1002/chem.201701978 -
Hydroxyl (O-H) confidence 1.0
“1A, b) presents absorptions at 3745 and 3740 corresponding to the vibration of OH groups located on the external and internal (i.e.”
Sacchetto 等 - 2013 - The interactions of methyl tert-butyl ether on hig DOI: 10.1039/c3cp51684a
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