The vibration spectra and structures of the hydrochlorides of urea, thiourea and acetamide. The basic properties of amides and thioamides

✍ Scribed by E. Spinner

• Book ID: 104333029
• Publisher: Elsevier Science
• Year: 1959
• Weight: 1002 KB
• Volume: 15
• Category: Article
• ISSN: 0371-1951
• DOI: 10.1016/s0371-1951(59)80294-0

✦ Synopsis

The i&a-red and Raman spectra, of the hydrochloridea and of the neutral molecules have been measured. The spectra show that the structures of the cations are NHsCO~H,, NH&&H, and CHsCO&H, respectively; no spectrum of the cation of thioacetamide could be obtained.

The postulate of extensive delocalization of the unshared nitrogen electrons in these substances, leading to partial double bond character of the CN bonds, is hard to reconcile with (a) the preferred site of proton addition, (b) the spectral results in the caaea of urea and acetamide;

however, no f%m conclusions can be drawn about the bonding in thiouree and its cation because of mixing of vibrations there. The structure and basic properties of amides and thioamides are discussed with reference to electronic theory.