Veladri Palla

Date of Award

8-2007

Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

Advisor

Howard H. Patterson

Second Committee Member

Jayendran C. Rasaiah

Third Committee Member

Bruce L. Jensen

Abstract

The present thesis discusses the heterometallic interaction of Pt(CN)4-2(d8) and Ag(CN)2-(d10) ions in the presence of +2 cations like Ba+2, Zn+2. Pure crystals of Pt(CN)4-2 or Ag(CN)2- ions with Ba(N03)2 and mixed metal crystals of Pt(CN)4-2 and Ag(CN)2- ions with Ba(NO3)2 were synthesized. Photoluminescence spectra of the synthesized crystals were taken at 77K, 4K and RT. At 4K the photoluminescence spectra of single crystals of pure Ba[Ag(CN)2]2 show a peak at 408nm and single crystals of pure BaPt(CN)4 show a peak at 464nm. At 4K the photoluminescence spectra of single crystals of the mixed metal system containing both Pt(CN)4-2 and Ag(CN)2- ions shows a new peak at 424nm along with the peaks that corresponds to pure Ba[Ag(CN)2]2 and pure BaPt(CN)4 . This new peak at 424nm is seen between the peaks at 408nm that corresponds to pure Ba[Ag(CN)2]2 and at 464nm that corresponds to pure BaPt(CN)4. This new peak corresponds to the heterometallic interaction of Pt and Ag ions. Also similar luminescence spectra were obtained with mixed metal powders of Pt(CN)4- and Ag(CN)2- ions with zinc as a +2 cation. A peak at 424nm that corresponds to a mixed metal transition is also seen in the case of mixed metal powders of Pt(CN)4-2 and Ag(CN)2- ions with zinc as +2 cation along with the peaks at 390nm and 464nm that corresponds to pure Ba[Ag(CN)2]2 and pure BaPt(CN)4 respectively. The luminescence spectra of the metal systems discussed in this thesis with Ba+2 and Zn+2 as cations differ in both the excitation and emission spectra, except for the emission peak corresponding to a mixed metal transition with both Pt(CN)4-2 and Ag(CN)2- ions. This is because of the different bonding nature of Ba+2 and Zn+2 cations. Ba+2 is ionic nature, whereas Zn+2 is covalent in nature. This difference results in a difference in the environment surrounding Pt(CN)4-2 or Ag(CN)2- clusters when the cation is changed from Ba+2 and Zn+2 which further bring changes in their luminescence properties.

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