Date of Award

Spring 1994

Degree Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Chemistry

Abstract

Ruthenium(II) polypyridine complexes have attracted considerable interest over the past two decades as possible photosensitizers in solar energy conversion schemes. Two approaches to improve their physico-chemical properties can be envisioned. The ligands can be modified or the complexes can be incorporated into an organized media. In this research resonance Raman (RR) spectroscopy is utilized to provide a detailed characterization for the structure and dynamics of free and zeolite-entrapped ruthenium (TI) complexes. The resonance Raman (RR) and the time-resolved resonance Raman (TR3) spectra for the tris(4-methyl-2,2'-bipyridine)ruthenium (II) complex, Ru(mmb)l+, and its methyldeuteriated analogue Ru(drmmb)/+ are reported. The spectra are compared to those of tris(2,2'-bipyridine)ruthenium(II), Ru(bpy)/+, and tris(4,4-dimethyl, 2,2'bipyridine) rutheniufu(II), Ru( dmb )/+,and its methyl-deuteriated analogue Ru(d6-dmb )l+. The spectra for the ground state of the complex with the asymmetric ligand, mmb, are readily interpretable in terms of vibrationally isolated fragments (pyridine and 4- methylpyridine) with the exception of a few modes which are assignable to stretches of the inter-ring and adjacent bonds. The TR3 spectra are shown to be consistent with slight polarization of the 3MLCT excited-state charge distribution toward the pyridine fragment of the chelated anion. The resonance Raman (RR) and the time-resolved resonance Raman (TR3) spectra of tris(5-methyl-2,2'-bipyridine)ruthenium(II)complex is also reported and compared to the corresponding ruthenium(II) polypyridine complexes. The findings are similar to these for the tris(4-methyl-2,2'-bipyridine)ruthenium(II) complex. In addition to the studies above, studies involving an entirely new approach for constructing supramolecular systems was undertaken. The fundamental principles behind the construction of these systems are discussed and the preparation of these weakly interacting diad systems within the supercages of zeolite-Y is described. The photophysical properties of these systems have just begun to be studied and thus will not be discussed here.

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