Same here, it doesn't have any options for donations. At least not that I can see. Unless there is a step between finishing the first 3 potions and the donation?
When trying to donate to the library and you haven't researched everything in the library already, the game will tell you it. Doesn't the game tell you? Research everything in the library and then you can donate if you have the gold. Or is there something I am missing?
Okay, according to some other comment the donation box seems to be bugged I think.