[repetelww]

Well I guess this topic is more or less related to "traditional" organic chemistry, depending on your view of the subject matter.

For the past few months I have been working on some Host-Guest chemistry. I have an organic host that I synthesized after a great deal of work, and we are hoping to incorporate a guest molecule. For what I am attempting to do, the molecule needs to have a few basic characteristics: Small Molecule, Linear Molecule, UV/VIS active, a fair amount of emission at 570nm.

So from that I know that I am probably looking for a dye molecule that is red. After looking through many different dye molecules, I believe a dye under the trade-name Methyl Red would be a good fit for our application, and Nile Red might also work. However, being size constrained many dye molecules are not applicable. I was hoping that perhaps if anyone knew any others that seem to fit perhaps they could suggest to help me out.

Also, I have looked into metal complexes that could perhaps work, so if anyone knows any that fit the criteria, please share, I am quite open to possibilities.

Thanks.

[billnotgatez]

what red do you want
http://www.glidden.com/color/color-visualizer.do#path=colorPalette&cid0=&cid1=&cid2=&cid3=&cid4=&cid5=&cid6=&cid7=&cid8=

 

[repetelww]

The specific color of red does not matter so much. It is really the size of the molecule that is the constraining factor.

[Corribus]

Fluorescence is a rather limiting factor, particularly in the red.  You're pretty much limited to porphyrins, cyanine dyes, Ruthernium tris-bipyridine, and some of the fluorones (rhodamine family, and I'd include nile red here).  There might be some others out there.  And quantum dots, if you're willing to go that route.  Water solubility will limit you even further. 

What size and polarity are you looking for?  Cy3 (Cyanine-3) might be your best bet.  Fairly linear, emission max at 570, reasonably stable, inexpensive. 

See: http://en.wikipedia.org/wiki/Cyanine