The sample's infrared spectrum presented in Fig. 3 shows the
vibrational modes associated with the presence of the polyhydrated ascorbic acid molecules. The peaks of the infrared spectrum and their
corresponding interpretations are detailed in
Table 1. An L-ascorbic acid molecule contains two hydroxyl (OH)
groups attached to double bonded carbon atoms. nfrared spectrum
of the synthesized particle, however, does not show vibration
modes associated with the C¼C bond. The ascorbic acid may be
oxidized into dehydroascorbic acid. Dehydroascorbic acids in the
aqueous solution may have undergone hydration, thus forming
polyhydrated ascorbic acid molecules. The broad peak at 3198 cm1
associated with O-H stretching modes found in the intermolecular
bonded alcohol groups suggests the formation of networks of the
ascorbic acid molecules.
The infrared spectrum in Fig. 3 also shows unidentified peaks in
the range from 2569 to 1980 cm1
. These peaks are attributed to a
possible bond or a complex formed between the Cu atoms and the
polyhydrated ascorbic acid molecules. The ascorbic acid did not
merely coat the copper metal. Otherwise, it would have dissolved in
water. Instead, it formed a complex, which capped the molecules.
This capping may be only a few molecules thick and is too thin to be
visible in the electron micrographs |