Studies of organometallic ions in the gas -phase by using Fourier transform ion cyclotron resonance mass spectrometry
Abstract
Fourier transform ion cyclotron resonance (FTICR) mass spectrometry combined with laser desorbtion technique is applied to study several types of novel organometallic ions in the gas-phase. The polyhydrido trimethylphosphine rhenium complex, ReH7(PMe 3)2, and fragment ions, ReHx(PMe3) 2+/–, were generated and examined in the mass spectrometer to determine their structures or characters. The ion-molecule reaction results indicate that ReH7(PMe3)2 prefers to lose molecular hydrogens, to demerit and to be attached by the electron rich atom/molecule. The σ-bond, Π-bond and M=S, M=O, M=CH2 bond ligand containing metal-ligand ions react with tert-butyl isocyanide to generate different products. The two kinds of imidoly ion/dipole complexes are formed as initial step for these reactions based on bond type and bond energy of the metal-ligand complex. Consequently, reaction mechanisms and product distributions depend on generated imidoly ion/dipole complexes. The generation and characterization of transition-metal distonic ions, which contain the metal charge site spatially separated from the radical site are reported. The fluorine-substituted metal distonic ion IFe+C 6F4• was formed by rearrangement of a conventional metal cation, Fe+C6F4I. The metal distonic ion structure of this ion was demonstrated by ion-molecule reactions and collision-induced dissociation. Fluorine substitution on the benzene ring facilitates iodine atom migration by the strong inductive withdrawal of electrons and forming the dπ-pπ bond. However, the non-fluorine-substituted metal ion, Fe+C6H4I does not rearrange to the metal distonic ion structure. Nascent metal distonic ions, Fe +C6F4• and Fe+C 6H4•, rearrange to linear diyne-ene structures through metal biradical para-benzyne as intermediates. The study of novel transition-metal distonic ions reveals a whole new area of organometallic ion chemistry.
Degree
Ph.D.
Advisors
Jacobson, Purdue University.
Subject Area
Analytical chemistry|Organic chemistry
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