Oxygen-containing compounds infrared spectra

If the unknown, neutral, oxygen-containing compound does not give the class reactions for aldehydes, ketones, esters and anhydrides, it is probably either an alcohol or an ether. Alcohols are readily identified by the intense characteristic hydroxyl adsorption which occurs as a broad band in the infrared spectrum at 3600-3300 cm-1 (O—H str.). In the nuclear magnetic resonance spectrum, the adsorption by the proton in the hydroxyl group gives rise to a broad peak the chemical shift of which is rather variable the peak disappears on deuteration. 

A coordination number of 7 does not seem likely for chromium (III) also, the infrared spectrum indicates that this compound contains uncoordinated hydroxyl groups. The similarity of the visible-ultraviolet absorption spectra of [Cr(HO-A)2] and [Cr(AcO-A)2] (above) is further evidence of the identical character of the donor groups in both compounds, and hence, hydroxyl groups appear to be uncoordinated in the former. We must seek an explanation not involving coordination of the hydroxyl oxygen to chromium (III). 

Given that a molecule contains oxygen, how could an infrared spectrum of such a molecule be used to find out whether the compound was a carboxylic acid, a phenol, an alcohol or an ether ... 

Compound A (C4H602) has an index of hydrogen deficiency of 2. With two oxygen atoms and a peak in the infrared at 1760 cm-1, it is likely that one of the elements of unsaturation is the carbon-oxygen double bond of an ester. The H NMR spectrum contains a three-proton singlet at 8 2.1 ppm, which is consistent with a CH3C unit. It is likely that compound A is an acetate ester. 

The inhibition performances of honey could be explained as follows Fourier transform infrared (FTIR) spectrum in Figure 3 demonstrates that honey is a mixture of various compounds containing carbon (C), oxygen (polyphenols), nitrogen and sulphur (glucosinolates) which all can be adsorbed on the corroded metal (Radojcic et al., 2008). The bands at about 1055.3 and 1418.1 cm"i are consists of C, O, H and N atoms, meanwhile the peak at 1255.6 cm i is due to sulphur (S). A band appearing near 2935.7 cm i proves the existence of C, O and H atoms in NH. A band located at 3355.1 cm"i corresponds to O, N and H atoms. 

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