Investigation of Solvent Effects on Carbonyl Stretching Vibrational Frequency of Camphor
No Thumbnail Available
Date
2021-08-30
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Solvent effects on the carbonyl stretching vibrational frequency of Camphor were
investigated. The solvents were chosen to cover wide polarity range and include carbon
tetrachloride,2-propanol, methanol, and acetonitrile. For protonic and aprotonic solvents
two distinct behaviors were observed. In non-protonic or aprotonic solvent there seems little
or negligible polarity dependent shift was observed. The situation is different for protonic
solvent where strong blue shift was obtained. These facts could be attributed to the low
dipole moment of the chromophore (in aprotonic solvents) and hydrogen bonding with
solvent molecules. The broadness in protonic solvents compared to that in aprotonic
solvents support the suggestion made earlier and indicate the Band I is due to mainly
hydrogen bonding. Similarly, the solvent dependence of Band II analyzed. Generally, a
bathochromic shift was observed though the peak in acetonitrile appears at higher
frequency than both protonic solvents. Additional shoulder peak of absorption was observed
in methanol and propanol solvents. What is striking was that the shoulder is approximately
same as that found in CCl4 solution. This may be due to complex (hydrogen bonding)
between the carbon of carbonyl and oxygen of the alcohols.
Description
Keywords
Camphor, Carbonyl Carbon, Solvent, Hydrogen Bonding