Solution Raman spectrum and normal-co-ordinate analysis of dioxygen difluoride

Abstract

Raman spectra of O, F, in CCIF, solution are reported for the first time. A vibrational assignment is proposed based on polarisation data. A reinvestigation of the vibrational-potential function and a calculation of the barrier height to internal rotation have been made. THE i.r. spectrum of 02F2 was first observed using matrix-isolation techniques by Brown,l by Spratley et aZ.,, and by Arkell,3 the latter two groups of workers being primarily concerned with the i.r. spectrum of 0,F. None of these workers, however, observed the complete spectrum of 02F,. Loos et aL4 have recorded the complete i.r. spectrum of solid 02F2 and, in an earlier paper,5 we reported the solid-state i.r. and Raman spectra and also the i.r. spectrum of 02F2 trapped in various matrices at 20 K. Noble6 has carried out a normal-co-ordinate analysis of 0,F and Loos et aL4 have undertaken one for 02F2 using these solid-state i.r. frequencies.This paper describes Raman polarisation studies on 0,F2 dissolved in CClF, at about 190 K. This work was mentioned in proof in a previous publication5 and confirms an assignment of lower-frequency modes given therein which differs slightly from that of Loos et aL4 Using this assignment, and solution-phase frequencies, we have reinvestigated the vibrational-potential function of this unusual molecule. EXPERIMENTAL

The Structural Chemistry of Acyclic Organic Peroxides

“…In peroxides of the type R 1 −O−O−R 2 (for R 1 , R 2 = alkyl, aryl, vinyl, alkynyl) a progressive increase of the peroxide dihedral angle with the steric demand of R 1 and R 2 is observed ( 53 . These effects may be explained by taking hyperconjugation between a lone pair at oxygen (n) and the σ * orbital of the F−O bond into account.…”