| The underlying theme of this dissertation is the examination of systems within constrained media. Using fluorescence and phosphorescence spectroscopy, o-methyldiphenylidene in a glass and studied energy transfer between Gd3+ and selected organic molecules within the gadolinium-exchanged zeolite GdNaX.; When o-methyldiphenylidene and d3- o-methyldiphenylidene are photolyzed in a methylcyclohexane glass at 77 K, a kinetic isotope effect of 2.5 is observed, indicating that a hydrogen a conformational change is proposed to be the rate determining step of this reaction.; GdNaX was prepared by ion-exchange with NaX and no crystallinity loss was found upon characterization with X-ray powder diffraction. The luminescence of Gd3+ within GdNaX was determined to be nearly identical to that of Gd3+ in water with emission maxima at 306 and 311 nm (λex = 273 nm) and excitation maxima at 273, 276, and 279 nm (λem = 311 nm). The lifetime of Gd3+ luminescence was determined to be 6.78 ms in GdNaX and 1.11 ms in methanol.; Energy transfer was observed between Gd3+ and 2,2 ′-bipyridine (bipy) when bipy was absorbed into the zeolite, GdNaX. Evidence for energy transfer includes bipy fluorescence emission at 440 nm upon sensitization with Gd3+, as well as an increase in the lifetime of bipy emission from 15 ns to 633 μsec upon changing from direct (λex = 375 nm) to sensitized (λex = 273 nm) bipy excitation.; Selected other organic molecules, including anthracene, pyrene, benzene, pyridine, and 2,4-pentanedione, were also examined for energy transfer with Gd3+. Both anthracene and pyrene reacted with GdNaX, rendering them unsuitable for study, and neither benzene or pyridine exhibited energy transfer to Gd3+. 2,4-Pentanedione was observed to form a complex with Gd3+ in solution, however, the positioning of its excitation and emission maxima (274 nm and 322 nm, respectively) and the presence of long-lived phosphorescence emission from triplet 2,4-pentanedione render this compound unsuitable for energy transfer studies. |
