Experimental and Theoretical Characterization of the Oxygen-Coordinated Donor−Acceptor Adducts of COCl₂, COClF, and COF₂with AsF₅and SbF₅

Abstract

When reacted with an excess of the corresponding carbonyl halides, AsF 5 and SbF 5 form the following 1:1 adducts: COCl 2 ·AsF 5, COCl 2 ·SbF 5, COClF·AsF 5, COClF·SbF 5, COF 2 ·AsF 5, and COF 2 ·SbF 5 . All adducts are unstable at ambient temperature, and their dissociation enthalpies were determined from the dissociation pressure curves. Vibrational and multinuclear NMR spectra and theoretical calculations show that all compounds are oxygen-coordinated donor−acceptor adducts, and that the strengths of the oxygen bridges increase from COF 2 to COCl 2 and from AsF 5 to SbF 5 . Full normal coordinate analyses of the adducts demonstrate that the bridging modes occur below 100 cm - 1, justifying the frequently used approximation of analyzing similar weak adducts in terms of their separate donor and acceptor molecules.