O-H Functional Groups

The O-H functional group of alcohols is easy to spot. Alcohols have a characteristic band in the range 3400 to 3650 cm-1 that is usually broad and intense. If present, it s hard to miss this band or to confuse it with anything else. 

The central oxygen atom in water (acting as Y) can hydrogen bond the hydrogens in the O-H functional groups of cellulose (the X-H unit) or... 

Intramolecular Reaction of Alkynes with N-H and O-H Functional Groups... 

The N—H functional group of amines is also easy to spot in the IR, with a characteristic absorption in the 3300 to 3500 cm-1 range. Although alcohols absorb in the same range, an N—H absorption is much sharper and less intense than an O-H band. 

In general, the increased efficiency of C—C bond cleavage observed for these substrates can be ascribed to two features a weakened C—C bond in the radical cation due to the presence of the second functional group and the greater acidity of the N-H or O —H functions compared to the a-C—H acidity of the aminium radical cation. 

However, it is clear that vibrational spectroscopy has considerable use beyond the identification of polymorphs and solvates. The infrared spectra obtained on the polymorphs of acetohexamide and selected derivatives has been used to study the tautomerism of the drug compound [127]. It was deduced in this work that Form A existed in the enol form, stabilized by the intramolecular bonding between the O—H and groups that produces a six-membered ring. Form B was characterized by the existence of the keto form, with the urea carbonyl group being intermolecular bonding to a sulfonamide N—H functionality. This behavior can be contrasted with that noted for spironolactone, where no evidence was found for the existence of enolic tautomers in any of the four polymorphs [128]. 

The carbon that bears the functional group is sp hybridized m alcohols and alkyl halides Figure 4 1 illustrates bonding m methanol The bond angles at carbon are approximately tetrahedral as is the C—O—H angle A similar orbital hybridization model applies to alkyl halides with the halogen connected to sp hybridized carbon by a ct bond Carbon-halogen bond distances m alkyl halides increase m the order C—F (140 pm) < C—Cl (179 pm) < C—Br (197 pm) < C—I (216 pm)... 

Chemical properties of isopropyl alcohol are determined by its functional hydroxyl group in the secondary position. Except for the production of acetone, most isopropyl alcohol chemistry involves the introduction of the isopropyl or isopropoxy group into other organic molecules by the breaking of the C—OH or the O—H bond in the isopropyl alcohol molecule. 

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