CMDITR Review of Undergraduate Research - Pluto - University of ...

chromatography (TLC) (5%EA in methylene
chloride) was performed on the irradiated and
non-irradiated solutions. Irradiated solution
showed separation into a light blue colored band
(non-degraded) as well as pale-yellow substance
(degraded FTC). With this data in hand, multiple
samples of degraded chromophore were
collected. Then, EA was dried out from those
solutions leaving the solid that had a brownishorange
color. NMR scan of that solid finally
showed some new and different peaks in
comparison to the NMR scan of the original,
non-irradiated solution of FTC (Figure 4).
The first NMR scan, acquired by Dr. Yi
Liao, showed some definite changes (Figure 4b).
There were peaks present in the aldehyde region,
changes in the aromatic region, as well as some
very strong peaks in the aliphatic region.
Because a number of the peaks pointed to
contaminants, the procedure was repeated and a
second NMR scan was taken showing very
similar peaks as on the first one but with a large
bump in the 2.2-2.5ppm region missing. All of
the conclusions about the structure of the
degradation products were made based on that
scan.
Conclusion
The preliminary data that have been
gathered from these experiments provide some
ideas about the degradation mechanism of FTC
under UV light. While conditions of degradation
were established only in EA, they give a
possibility of establishing a step-by-step
degradation mechanism for FTC by providing
controllable degradation conditions. For now, it
is possible to say that degradation products
contain aldehydes which may be due to the
oxygen reacting with FTC at one of the double
bonds (Figure 5). Which double bond
specifically is still to be determined, but at this
moment double bond “a” is considered for
further study since one of the aldehydes made
from it is commercially available. It is possible
to take NMR of that aldehyde and compare it
with the available NMR of the degraded FTC
(Figure 6). If a match occurs, it will be possible
to draw some more reliable conclusions. Once
accurate structures can be identified it will be
possible to further study a step by step
degradation of EZ-FTC as irradiation time is
increased as well as degradation mechanism at
telecommunications wavelengths.
38 CMDITR Review of Undergraduate Research Vol. 1 No. 1 Summer 2004