[darkdevil]

Hi all,

I have a question on separating my organotin compounds. This is how I made my organotin:

I am sure that I have obtained some products, as there is no problem for me to obatin some Stille Coupling products when I used the organotin in excess.

However I still need a pure organotin compound to perform Stille Coupling reaction with exact stoichiometry. I am not familiar with organotin compounds, the only thin I know is that they are VERY toxic. I tried to purify with the product with silica gel and everything was lost. I was told by a colleague that these compounds are sensitive to acidic environment. Do i really need to use Al2O3 for flash chromatography? or Can I "neutralize" the silica gel first and how can I do so?

THank you!

[MOTOBALL]

I have read of the use of NH4OH solution to prewash silica gel; this was with a derivatized carbohydrate which lost an acid-labile group during chromatography on regular silica gel.

[darkdevil]

I never knew organotin compounds were that acid sensitive. I performed TLC with silica gel plates and the product spots were seen on the TLC plate. But then when I actually did the flash chromatography, no product spot was found and I got only my starting materials after quite an unusually long waiting for any spots to come out

[TheUnassuming]

Do you see smearing on the TLC of your material?  A good way to test for silica decomp is to run a 2-d TLC.  Basically run the TLC on a square cut plate on one side, then flip it 90º and run it again.  If you are getting silica decomp you should see your product spot making multiple spots on the second run.