Infrared Absorptions of Functional Groups

APPENDIX 2B IR Characteristic Infrared Absorptions of Functional Groups... 

TABLE 15.3 Typical Infrared Absorptions of Functional Groups" continued)... 

The purpose of this book is to provide a simple introduction to characteristic group frequencies so as to assist all who may need to interpret or examine infrared and Raman spectra. The characteristic absorptions of functional groups over the entire infrared region, including the far and near regions, are given in tables as well as being discussed and amplified in the text. 

Infrared absorption spectra of heteropyrans have been used mainly for the identification of functional groups. Assignments of the bands belonging to heterocyclic bond vibrations (C=C, C—S, C—Se, C—Te) have not been common. As a rule, 4W-heteropyrans exhibit maxima at higher wave numbers than 2//-isomers. Typical IR absorption maxima for heteropyrans are shown in Table X. 

Infrared absorption spectra have frequently been used in structure proof of imidazo[2,l-h]thiazoles, but identification of functional groups is the... 

Predict the characteristic infrared absorptions of the functional groups in the following molecules. 

Infrared spectroscopy is an extremely useful tool for detecting the presence and type of functional group. Strong absorption bands are characteristic of various classes of monosaccharides containing a carbonyl group. 

Infrared Absorption Frequencies of Functional Groups Table 4.7, Saturated Compounds sp sharp, br = bfoad, (w) = weak, (s) = strong... 

When infrared spectroscopy is applied to humic substances, a number of functional groups can be determined (see MacCarthy and Rice, Chapter 21 in this book). The procedures for the preparation of KBr pellets and recording of the spectra have been described elsewhere (Robin et al., 1977 Debyser and Gadel, 1981). The spectra can be compared in a quantitative way (for related samples or compounds) by means of planimetry of the absorption bands. 

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