I. GAS PHASE CHEMISTRY AND PHOTOCHEMISTRY OF CARBON(7)HYDROGEN(7)OXYGEN(+). II. GAS PHASE CHEMISTRY AND PHOTOCHEMISTRY OF IONS GENERATED IN REACTIONS OF ATOMIC METAL IONS WITH NITROALKANES AND ALKYL NITRITES (PHOTODISSOCIATION)

CAROLYN JEANE CASSADY, Purdue University

Abstract

Gas phase chemistry and photochemistry of organic and inorganic ions have been investigated using ion cyclotron resonance (ICR) and Fourier transform mass spectrometry (FTMS). The techniques employed for determining ion structures include ion-molecule reactions, collision-induced dissociation (CID), and photodissociation. A study of C(,7)H(,7)O('+) ions from a series of compounds yields evidence for five unique structures and demonstrates the utility of FTMS for the elucidation of isomeric species. In addition, photodissociation and CID studies have been performed on the molecular ions of various substituted toluenes. The reactions of a series of late transition metal ions with methyl nitrite have been studied and are found to proceed through a common intermediate. The products resulting from this intermediate are dependent on the metal ion. The reactions of nitromethane with these metal ions have also been investigated, with the dominant reaction pathway observed being a nitro-to-nitrite rearrangement. The reactions of Fe('+), Co('+), Ni('+), and Rh('+) with a series of nitroalkanes are outlined. These ions exhibit a rich and unusual chemistry in their reactions with nitroalkanes. Evidence is presented for a long-lived (>1 ms) reaction intermediate of C-N insertion. The D(Fe('+)-OH) and D(Co('+)-OH) bond energies have been determined by deprotonation reactions and by photodissociation. Reasonable agreement is observed for the two methods with values of D(Fe('+)-OH) = 77 (+OR-) 6 kcal/mol and D(Co('+)-OH) = 71 (+OR-) 6 kcal/mol obtained by proton transfer and D(Fe('+)-OH) = 73 (+OR-) 3 kcal/mol and D(Co('+)-OH) = 71 (+OR-) 3 kcal/mol obtained by photodissociation. Photodissociation is shown to be a relatively simple technique which gives accurate metal ion-ligand bond energies and which may be applied to many inorganic systems. The reactions of FeOH('+) and CoOH('+) with alkanes have been studied and are found to proceed by both C-H and C-C insertion. No evidence is seen for ROH formation at the metal center. The MOH('+) ions appear to be less reactive than the bare metal ions.

Degree

Ph.D.

Subject Area

Analytical chemistry

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