Structure of heteroassociates formed in the HF-(C2H5)2O liquid system

The aim of this work was to determine the structure of stable heteroassociates (HAs) with the stoichiometric ratios 1:2, 2:1, and 4:1 of molecules formed in the HF-(C2H5)2O binary liquid system. The stretching frequencies of HF molecules found for each HA using a special procedure for processing IR spectra were compared with the calculated frequencies VHF of the stable molecular complexes (HF)m ((C2H5)2O)n (m = 1, 2, 4, 8; n = 1, 2) with different topologies by the density functional method (B3LYP/6-31++G(d,p)). As a result, it was shown that the most stable (among H-bonded complexes with the same stoichiometric ratio of molecules) HAs HF((C2H5)2O)2, (HF)4 ((C2H5)2O)2, and (HF)8-((C2H5)2O)2 formed in HF solutions in diethyl ether. All of them had a cyclic structure and a common peculiarity of structure: only one lone electron pair of the oxygen atom of the (C2H5)2O molecules is involved in hydrogen bonding.