Experimental and Calculational Studies of the Interactions of BF3 with Fluoroethers

BF₃ was co-condensed with (C₂H₅)₂O, (CF₃CH₂)₂O, and (C₂F₅)₂O in excess argon at 15 K. Infrared spectra of the matrices showed a definite Lewis acid-base interaction between BF₃ and diethyl ether; a weak but definite interaction with bis(2,2,2,-trifluorodiethyl)ether, and no observable interaction with perfluorodiethyl ether. Molecular orbital (MO) calculations complemented the experimental observations by revealing that fluorine atoms on the ethers decreased electron localization about the oxygen atom. Thus, the experimental data and MO calculations indicated a clear trend between strength of interaction with BF₃ and the degree of ether F substitution. The implications of the results for commercial perfluoro ether lubricant/metal oxide surface interactions are discussed.