Studying On The Gas Phase Reactions Of Ferrocene Derivatives

With the development of mass spectrometry technology, it has been widely used in the study on the gas phase reactions for organic compounds. In this thesis, tandem mass spectrometry, isotopic labeling experiments and theoretical computations were applied to investigating the mechanisims of collision-induced dissociation in the electrospray ionization mass spectrometry for ferrocene derivatives.Firstly, the gas phase fragmentation mechanisms of N-phenyl ferrocene carboxamide derivatives were discussed. It was found that the amide oxygen was the most favorable site for protonation. However, the reaction was triggered upon a1,3-proton transfer to a "dissociative protonation site":amide nitrogen or ipso-carbon of ferrocenyl ring. Loss of aniline and loss of phenyl isocyanate were observed as the two major competitive routes, which were controlled by transition states of proton transfer reactions confirmed with the help of theoretical calculations. Moreover, the intensities of product ions were influenced by the substituents at phenyl ring. Electron-withdrawing groups at phenyl ring were in favor of neutral loss of substituted aniline, whereas the electron-donating groups strongly favored lossing the substituted phenyl isocyanate.Secondly, in the fragmentation of protonated benzoylferrocenes, the characterized product ion:ferrocinium cation was observed, which was proposed from a proton transfer from carbonyl oxygen to ipso-carbon of ferrocenyl ring followed by electron transfer reaction in [substituted benzoyl/ferrocene] ion-neutral complex. The mechanism was then investigated by theoretical calculations and the abundances of ferrocinium cation were related to the electron affinities of the benzoyl cations. When the complex contained an electron acceptor(substituted benzoyl cation) with higher electron affinity, the electron transfer reaction was more efficient, vice versa.Finally, the fragmentation of a series of N-phenyl ferrocene imine derivatives was studied. The proton can transfer to the dissociative protonation sites and trigger the fragmentation. Major product ions resulted from electron transfer and proton transfer reactions via ion-neutral complexes, respectively. The intensities of ferrocinium cation were related to the electron affinities of the N-phenyl imine cations, whereas the formation of protonated ferrocene were controlled by the difference in proton affinity between the ferrocene and substituted isocyanobenzene within the complex. The proposed mechanisms are supported by theoretical study and isotopic labeling experiments.