Some years ago (circa 1995), I learned about the magic of arsenic trichloride. I think it was Karl Christe (when he was still at the Edwards Air Force Base in California), who told me about this wonderfully “benign” material. At that time, I was desperately trying to dissolve a polycyclic aromatic molecule. Apparently, when nothing else works, arsenic trichloride is supposed to solve all your problems, particularly when it comes to dissolving polyaromatics. For many years I have been trying to find the original source describing this wisdom and, as luck would have it, accidentally came across the paper I have been looking for. Here it is, so put it to test if you are brave enough. According to the authors of this old work, arsenic chloride is cheaper than deuterated chloroform. I am not sure about that, but I know several people who swear by the unique properties of this liquid. You might ask: “So did you give it a shot?”. Nope, I did not. I am not that brave after all!
another crazy solvent for polyaromatics is 1:1 mix of benzene with perfluorobenzene. It has a melting just above room temperature (24C), but in liquid form it can be used to make stable high concentration dispersions of graphene. I wonder if anyone tried the deuterated version, and let it crystallize inside the NMR magnet – the 1:1 complex crystallizes in long uninterrupted pi-stacked columns of alternating benzene and C6F6 molecules, it is quite possible the strong magnetic field would align these along the crystallographic axis (co-crystals like these could be a useful alternative to metalorganic framework technique for solving X-ray of molecules that do not crystallize). The nice thing about the 1:1 cocrystal is its high volatility – it still boils at 80C.
This is great, thanks. Sounds like a good combination of properties to dissolve a range of recalcitrant aromatics.