Brain&Force - 17-3-2016 at 22:18
Even though I have relatively limited home lab facilities, I was able to make an unusual compound - dysprosium phthalate - that happens to be highly
fluorescent!
The compound is extremely easy to make. Just get any phthalate salt and any dysprosium salt (I used dysprosium sulfamate produced from the reaction of
dysprosium metal with sulfamic acid in water, and sodium phthalate from reaction of phthalic anhydride with sodium bicarbonate) and mix them. I used
an excess of phthalate because dysprosium is expensive of course.
On addition, a cloudy suspension forms, which begins to settle after a few minutes. On exposure to a commerically available CFL black light, it glows
a bright teal color.
I'm going to try the same thing with other lanthanides and figure out if I can get more fluorescent materials. What might be really interesting,
though, is whether substituting the phthalate ring can affect fluorescence or other interesting properties of the complex. I made this compound after
reading this paper which synthesized the compound in a much more complicated manner, likely to get good crystals for the x-ray diffraction experiments.
(They used potassium hydrogen phthalate and dysprosium nitrate, sealed in a PTFE container and heated at 160 °C for 3 days, then slowly cooled it
down to form crystals.) One of their unexpected findings is that the deep blue transition is more prominent than the yellow one, which is apparently
the opposite of what most fluorescent dysprosium compounds do. I'd like to see if ring substituents can change the intensities of different emission
bands.
And for good measure, here's a picture. The fluorescence is not all that bright but the color is quite intense.
<img src=http://i.imgur.com/mjXnR1A.jpg width=800>
Chemist_Cup_Noodles - 14-4-2016 at 05:58
First off, how has this thread not gotten more replies? But I must ask, where do you get the dysprosium? I think I saw recently that China was
starting to choke up it's prices on the rare earth metals and exports of the rare earths was decreasing. Idk it might have been a long time ago and
they've loosened up again. Nevertheless, great post!
nezza - 15-4-2016 at 23:07
I have tried to repeat this with no success. My lanthanide salts do not give a precipitate with sodium phthalate or phthalic acid. Adding excess
hydroxide gives a precipitate, but it is not fluorescent.
morsagh - 16-4-2016 at 08:26
How do you know it is polymeric structure?