The donor-acceptor interaction of aluminium triiodide with organic molecules; effect of addition of various organic compounds on the isotopic exchange of iodine in the aluminium iodide-ethyl iodide liquid system

It is shown, that organic molecules for which a strong donor-acceptor interaction with aluminium triiodide can be expected, with formation of a molecular complex, cause a strong “exchange blocking” effect in the AlI3C2H5I liquid system. Independently of the amount of the added foreign compound, however, a significant part (about 20–30 per cent) of the radioiodine atoms primarily present in the metal iodide is transferred to the ethyl iodide in the first rapid period of the exchange. The suggest a significant role for intermediate compounds and/or solid-liquid surface exchange. Aromatic hydrocarbons and olefines which are supposed to form π-complexes with aluminium trihalides, cause no effect on the iodine exchange in the system investigated.