Chemical Reactivity of Ti~+Ion within Ti~+(CH2FCH2OH)_n Clusters

摘要

The ion-molecule reactions that proceed inside Ti~+(CH2FCH2OH)_n heterocluster ions were studied using a laser ablation-molecular beam/reflectron time-of-flight mass spectrometric technique.The mass spectra exhibit a major sequence of cluster ions with the formula Ti~+(OCH2CH2F)_m(CH2FCH2OH)_n(m=1,2),which is attributed to sequential insertions of Ti+into the O-H bond of ethanol molecules within the heteroclusters,followed by H elimination.The TiO+and TiFOH~+ions produced from the reactions of Ti~+with CH2FCH2OH are interpreted as arising from insertion of Ti~+into the C-O bond,followed by C2H5F and C2H4 elimination,respectively.The observation of Ti~+(H2O)(CH2FCH2OH)_n ions is attributed to the insertion of Ti~+ions into the C-O bond in the ethanol molecules,leading to a beta-H atom transfer and CH2CHF elimination.This reaction pathway presumably plays an important role as the cluster size increases.Ab initio calculations on the complexes of Ti~+with CH2FCH2OH molecules show that the minimum energy structure is that in which Ti~+is attached to the O and F atoms of fluorinated ethanol,forming a five-membered ring.The formation mechanisms and reaction energetics of the observed heterocluster ions are discussed.