[okerio]

I reduced 1,1'-diformyl ferrocene using lithium aluminium hydride to get 1,1'-ferrocene dimethanol. purity check on TLC indicate one spot however NMR indicate presence of extra peak which i cant account for. recrystallization has not proved useful. please help.
Douglas

[lavoisier]

First, I assume you ruled out the possibility that the extra NMR peak is a solvent or a reagent from any of the previous synthetic steps.
Second, you may try different TLC conditions, and/or bidimensional TLC, or even better, HPLC or HPLC-MS.
If you definitely have a new substance, but it gives just one additional peak in NMR, it must be either very simple or very similar to your product, if you see what I mean.
I'm assuming that your product has no obvious isomers, has it ? (like the one with the two aromatic cycles twisted, for instance)