²⁷Al NMR Study on the Solvation of Anhydrous AlCl₃ in Various Lewis Base Solutions

The solvation of anhydrous AlCl₃ in various Lewis base solvents has been investigated by ²⁷Al NMR spectroscopy. In rather concentrated ether, pentan-2-ol, tetrafuran, dioxane, dimethylsulfoxide solutions, peaks of 5-coordinated species of solvared complexes have been observed. The stereohindrance effects of ligands on coordination number of Al can been seen from ²⁷Al chemical shifts. In primary and some secondary alcohol solutions, 6-coordinated species can be formed because of smaller ligaed stereohindrance, and ²⁷Al signals are situated arround O ppm. In tertiary alcohol and ketone solutions, peaks arround 100 ppm which belong to 4-coordinated species are predominant. Ethers have greater stereohindrance and can not from 6-coordinated species with Alcl₃. Therefore no peaks arround O ppm can be observed in ether solutions. In diethylether and nitromethane solutions signal belooging to Al₂Cl₆ dimer has been observed.