Infrared photochemistry of metal ion complexes
Abstract
In this thesis, infrared multiphoton dissociation (IRMPD) of metal containing ions in the gas phase was investigated using Fourier transform mass spectrometry. About 47 ions are studied, and two of them are found photoinactive. Specifically, three distinct projects have been undertaken: (1) kinetics studies to determine infrared cross-sections, (2) the IRMPD of M(acetone)$\sb2\sp+$ (M = Al, Fe, Co, Cu, ScO), and (3) the IRMPD of M(alkenes)$\sp{+}$ (M = Fe, Co, Ni). Of these metal complexes, all were found to be photoactive at 10.6 $\mu,$ except Al(acetone)$\sp+$ and Ni(C$\sb2$H$\sb2$)(C$\sb2$H$\sb4$)$\sp+.$ Sustained off-resonance irradiation (SORI), a technique that mimics infrared activation, was also applied to many of these ions and the results were in agreement with IRMPD results. For kinetics studies, the infrared cross-sections for Fe(acetone-d$\sb6$)$\sb2\sp+$ and Co(C$\sb2$H$\sb4)\sb2\sp+$ were examined. The methods of obtaining those cross-sections and the difficulties associated with the measurements with the current instrument are discussed. In the acetone studies, IRMPD and collision-induced dissociation (CID) on M(acetone)(acetone-d$\sb6)\sp+$ for M = Al, Fe, Co, and Cu suggest that the two acetone ligands bind in an equivalent fashion with respect to the metal center. For ScO(acetone)$\sb2\sp+,$ loss of CH$\sb4,$ instead of loss of acetone, was observed under IRMPD. Its perdeuterated analog, however, produced loss of acetone-d$\sb6$ in addition to CD$\sb4.$ Perdeuteration was observed to increase the photodissociation rates for the acetone system. The IRMPD of M(alkene)$\sp+$ (M = Fe, Co, or Ni, alkene = $\rm C\sb2H\sb4, C\sb3H\sb6, C\sb4H\sb6, C\sb4H\sb8$ and $\rm C\sb5H\sb{10}$) was also investigated. Multiple products were observed for some of these ions. An explanation for these observation are given using energy diagrams. Unlike the acetone system, perdeuteration was observed to decrease the the photodissociation rates for the $\rm MC\sb4H\sb6\sp+$ system.
Degree
Ph.D.
Advisors
Freiser, Purdue University.
Subject Area
Chemistry|Chemistry|Radiation
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