Thin-Film Infrared Spectroscopy of Acetonitrile

✍ Scribed by Edward M. Kosower; Gil Markovich; Galina Borz

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 524 KB
• Volume: 8
• Category: Article
• ISSN: 1439-4235
• DOI: 10.1002/cphc.200700465

✦ Synopsis

Abstract

Acetonitrile and [D~3~]acetonitrile in the vicinal region of a planar AgX fiber contain linear dipole–dipole linked oligomers as shown by 1) comparison of infrared band intensity ratios in the gaseous and condensed phases and 2) remarkable plots of absorbance (CN stretch) versus time during evaporation from an AgX planar fiber element. The plots (CH~3~CN 2252 cm^−1^, CD~3~CN 2262 cm^−1^) reveal the presence of octamers, hexamers, tetramers, and dimers along with some heptamer, trimer, and monomer structures. A novel isotope effect arises from the somewhat smaller size of the CD~3~CN resulting in an increase in the CN band intensity. The organized oligomers may be termed pseudocrystals and are the main components responsible for absorption intensity in the infrared spectrum of acetonitrile, on the AgX planar fiber or in an IR cell.