Sciencemadness Discussion Board

Pheophytin

infrablue - 21-6-2021 at 06:29

Wanting to make some pheophytin complexes with various metals that have more than one oxidation state, to test the effect of light on the valence of the metal ion.

There's some kind of vivid green ground cover in the front yard so it seemed like a good source of chlorophyll.

Placed some of the leaves, cut up with scissors, into isopropanol and allowed to sit overnight. Liquid turned a nice deep shade of green, and the plant matter turned pale.

Took some of the liquid and slowly added HCl. The color changed to olive green. Allowed solution to evaporate, leaving behind a greenish-blue-black solid. Carefully washed the solid in water in hopes of removing MgCl2.

Added more IPA to the solid to redissolve it. Added a solution of CuCl2 in IPA and saw a color change from yellow-green to more of an emerald green.

Wish I could verify the reactions spectroscopically. From what info I can find, chlorophyll and pheophytin are both supposed to have strong red and blue absorption peaks, so would appear green as do these experimental results. But the copper salt is also green (maybe I should have chosen iron III or cerium :D ). Besides that, unrelated to this experiment, I was playing with electrolyzing nickel in HCl to NiCl2, I found my FeSO4, and a while back I'd made a little bit of PrCl3, almost everything in my experiment space right now is green.

j_sum1 - 21-6-2021 at 15:59

Sounds interesting. Sounds ambitious without good analytical equipment. It will be difficult to know exactly what you have produced. But you may well produce a range of interesting colours.

[edit]
I note that Wikipedia suggests isolation of pheophytin with a weak acid rather than the HCL you used.

[Edited on 22-6-2021 by j_sum1]

Fery - 21-6-2021 at 21:31

here a process of separation, there are more compounds in leaves:
https://sci-hub.st/10.1104/pp.3.2.211

rockyit98 - 22-6-2021 at 18:54

TRY Mn+2.

Chlorophyllin Chlorophyllin refers to any one of a group of closely related water-soluble salts that are semi-synthetic derivatives of chlorophyll, differing in the identity of the cations associated with the anion. Its most common form is a sodium/copper derivative used as a food additive and in alternative medicine. As a food coloring agent, copper complex chlorophyllin is known as natural green 3 and has the E number E141https://en.wikipedia.org/wiki/Chlorophyllin

[Edited on 23-6-2021 by rockyit98]

j_sum1 - 22-6-2021 at 19:21

Just looking at this, it might be possible to hydrolyse the ester bond and isolate this beasty alcohol.


figure.png - 69kB

Has anyone ever tried it?