UKnowNotWatUDo - 2-4-2011 at 15:40
I know some organic molecules with appropriate pKa's can be deprotonated to yield colored anions such as Fluorene, Diphenylacetic Acid,
Diphenylacetonitrile, etc. In all of these compounds there seems to always be two aromatic rings, which I'm assuming is a large part of what makes
these C-H bonds at all acidic. Would it be possible to indirectly assess the nucleophilicity of these organic anions by adding a suitable electrophile
and measuring with a colorimeter? Or are some of them simply too sterically hindered? Also if anyone has any other examples of organic compounds that
form colored anions and where they could be acquired that would be great. I'm not sure if any of them are very touchy compounds to buy, but I have a
large amount of Potassium t-Butoxide leftover and decided that this was an interesting project.
Contrabasso - 3-4-2011 at 00:33
You might find something in the structures of the colour developers used in film processing. Note that the emulsion on the film contains part of the
colour creating molecule and the developer contains the rest.
By now a lot of the patents will be publicly available as a primary research tool. There are a few resources with DIY formulations for colour
processing that will give you the chemical names for the colour developers ( known as CD-1 through to CD-4 ) BUT the in emulsion couplers are more
securely guarded by the major companies.
Also look at the range of indicators available for pH and specific ions, there is a huge catalogue of chemicals that have and change colour with their
environment