PROTON AND ALKALI METAL IONS ATTACHED TO ALKYLPEROXYL RADICALS: STRUCTURE AND STABILITY OF M+-CnH2n+1O2 (M = H, Li, Na, K; n = 1 ~ 3) COMPLEXES

Abstract

The structure and stability of the still experimentally unknown M +- C n H 2n+1 O 2 ( M = H , Li , Na , K ; n = 1 ~ 3) complexes were theoretically investigated via density function theory at the B3LYP/6-311+G(3df,2p)//B3LYP/6-311G(d,p) level. The addition of alkali metal ions ( Li , Na , and K ) to C n H 2n+1 O 2 are found to form only one stable structure, while proton transfer reactions with C n H 2n+1 O 2 produce two isomers except for CH 3 CH 2 CH 2 O 2. The optimized geometries and Mulliken population analysis indicate that the M + ( M = Li , Na , K )- C n H 2n+1 O 2 complexes exist as ion-dipole molecules. Our prediction for the affinity energies of M + to C n H 2n+1 O 2 are 165.4, 178.0, 181.9 and 176.8 kcal/mol ( H +); 34.3, 36.4, 37.5, and 38.4 kcal/mol ( Li +); 24.4, 26.1, 26.9, and 27.5 kcal/mol ( Na +); and 17.5, 19.2, 19.6, and 20.0 kcal/mol ( K +), respectively. Thus, these values suggest that C n H 2n+1 O 2- M + ( M = H , Li , Na , K ) complexes could be detected as stable species in gas phase at room temperature by ion attachment mass spectrometry.