Structure-reactivity studies of organometallic cations in the gas phase by using Fourier transform mass spectrometry
This dissertation describes four areas of study involving organosilicon and organosilicon transition metal ion chemistry in the gas phase: structural elucidation of isomeric silylenium ions by using specific ion-molecule reactions, rearrangement of nascent [alpha]-silyl-substituted carbenium ions, dyotropic rearrangement of organo-silylenium ions, and generation and characterization of transition metal-silylene and -silene cationic complexes. Ion-molecule reactions with methanol and isotopically labeled ethene were developed that can structurally distinguish isomeric alkylsilylenium ions. The unimolecular rearrangement of simple nascent [alpha]-silyl-substituted carbenium ions in the gas phase was explored. These incipient carbenium ions undergo 1,2-migration from silicon to carbon to yield a more stable (thermodynamically) silylenium ion with the following relative migratory aptitudes. The mechanism of ethene extrusion for unimolecular dissociation of (CH[sub 3])[sub 3]Si[sup +] was studied. CAD combined with isotopic exchange reactions suggest that (CH[sub 3])[sub 3]Si[sup +] and (C[sub 2]H[sub 5])(CH[sub 3])Si H[sup +] interconvert upon activation. A mechanism involving a concerted 1,2-hydrogen/1,2-methyl migration is proposed. The first example of efficient ion isomerization, (C[sub 2]H[sub 5])SiH[sup +][sub 2] to (CH[sub 3])[sub 2]SiH[sup +], without subsequent dissociation by using sustained [open quotes]off-resonance[close quotes] collision-activated dissociation (SORI-CAD), is also described in the gas phase. The first examples of generation and characterization of isomeric iron-silylene and -silene cationic complexes have been presented. The structure-reactivity characteristics of these species have been explored by both CAD and ion-molecule reactions with ethene, water, and benzene. CAD failed to yield structural information. Reaction with ethene-D[sub 4] and ethene-[sup 13]C[sub 2] provided evidence for formation of iron-silene and iron-silylene species.
- Research Organization:
- North Dakota Univ., Grand Forks, ND (United States)
- OSTI ID:
- 7243134
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
IRON COMPLEXES
CHEMICAL REACTION KINETICS
MASS SPECTRA
STRUCTURAL CHEMICAL ANALYSIS
ORGANIC SILICON COMPOUNDS
ACTIVATION ENERGY
CATIONS
FOURIER TRANSFORM SPECTROMETERS
ORGANOMETALLIC COMPOUNDS
SILICON COMPLEXES
CHARGED PARTICLES
COMPLEXES
ENERGY
IONS
KINETICS
MEASURING INSTRUMENTS
ORGANIC COMPOUNDS
REACTION KINETICS
SPECTRA
SPECTROMETERS
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties