Nearly symmetrical hydrogen bonds in the gas phas

The relationship between structure and energetics of nearly symmetrical hydrogen bonds has been studied in the gas phase via ion cyclotron resonance spectrometry. Investigations on ion molecule complexes allow access to ionic systems with nearly symmetrical hydrogen bonds.;The relationship between structure and energetics of nearly symmetrical hydrogen bonds was studied in alcohol/fluoride complexes. Using measured alkoxide and complex ion electron affinities, and appropriate neutral binding energies allow us to estimate the hydrogen bond strength in the complexes. Only alcohol/fluoride ions made with alcohols more acidic than HF photodetach; if ROH is more acidic than HF the structure is $rm ROsp-{cdot}HF,$ if ROH is less acidic than HF the structure is $rm ROH{cdot}Fsp-.$ The results show no evidence for unusual structural change or stabilization when a hydrogen bond forms between two acids with similar acidities.;We investigate hydrogen bonding interactions of silanols using alcohol/siloxide complex ions. When a silanol and an alcohol of comparable acidity are complexed, silanols resemble alcohols, and their complexes are stabilized by hydrogen bonding. Silanols are more strongly aggregated in condensed phase, but in gas phase alcohols form stronger hydrogen bonds.;Gas phase reactions of benzyl and methoxide anions with alkyl formates and other esters are studied and compared in an attempt to generate benzyl/methanol complex. Although these anions have similar basicities, in many cases the reaction pathways differ.;The non observation of photodetachment of simple siloxide ions is discussed in terms of their geometry which affects the cross section for photodetachment via the Franck-Condon factors. A theoretical study on the trimethylsiloxide ion, and radical showed a large geometry change. With a sufficiently poor geometric overlap, the Franck-Condon factors can reduce the photodetachment transition intensity and photodetachment is not observed.;We accessed the intermediate NOHF$sp-$ of a proton transfer reaction which occurs with a spin change. The complex NOHF$sp-$ was allowed to react with various neutrals, and NO$sp-,$ fluoride, or electron transfer products were observed. Based on photodetachment spectroscopy results and ab initio calculations we inferred that the complex structure is $rmsp3NOsp-{cdot}HF,$ consistent with the reactivity observations.