What absorbs at 3649 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 3649 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.

Возможные назначения функциональных групп

Ранжирование отражает накопленные литературные данные, а не единственное авторитетное правило. Всегда проверяйте в контексте вашего образца.

Possible materials

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 3649 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.

Литература, лежащая в основе этих назначений

• достоверность 1,0

  “IR peaks at higher ranges, 3380 cm-1 and 3649 cm-1, corresponding to N-H stretching [58], and O-H stretching [56], respectively.”

  Thermal Hazard and Smoke Toxicity Assessment of Building Polymers Incorporating TGA and FTIR—Integrated Cone Calorimeter Arrangement DOI: 10.3390/fire5050139
• Hydroxyl (O-H) достоверность 1,0

  “3b) such as hydroxyl, Ti-O cm-1, cm-1, films23, υ υ υ υ ethyl, acetyl and ethoxide in the shows stretching's for at 3649 at 3445 CH2,”

  Ghann 等 - 2017 - Fabrication, Optimization and Characterization of DOI: 10.1038/srep41470
• N h достоверность 1,0

  “Explicit assignment in text”

  Fabrication of Chitosan Nanofibers Containing Some Steroidal Compounds as a Drug Delivery System DOI: 10.3390/polym14102094
• Hydroxyl (O-H) достоверность 1,0

  “Therefore, the hypothesis emitted in -1 -1 In contrast, IR bands at 3649 cm and 1741 cm correspond to the previous publication [8] suggesting the presence of nodules of the phenol and ester functions of AO completely dissolved into the AO c”

  Physico-chemical analysis of a silane-grafted polyethylene stabilised with an excess of Irganox 1076®. Proposal of a microstructural model DOI: 10.1016/j.polymdegradstab.2020.109453
• Acetate достоверность 1,0

  “cm-1 cm-1 777 (C-H bending), 1134 1158 1158 (C-O stretching), 3649 and 3662 R2 (O-H stretching)].”

  Relationships in Gas Chromatography—Fourier Transform Infrared Spectroscopy—Comprehensive and Multilinear Analysis DOI: 10.3390/separations7020027
• достоверность 0,8

  “attributed to O-Si asymmetric stretch”

  Sadeghzadeh 和 Zhiani - 2019 - Photooxidation of triarylphosphines under aerobic DOI: 10.1039/c8ra09721f