Date of Award

2011

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

Assefa, Zerihun Dr.

Abstract

This work presents basic research in the area of lanthanide spectroscopy that could have the potential in chemical sensor technology. As part of the overall theme of developing synthetic scheme that may remove water from lanthanide inner sphere coordination we have targeted phosphines oxides. The synthesis of lanthanide TPAO compounds have been carried out by a reaction of Ln3+ trichloride hexahydrate and TPAO in solvent system containing water. The TPA system was particularly targeted because of its unique property of having a small cone angle (102◦ ) and water solubility and stability. We have attempted to coordinate up to four TPAO into the Eu inner sphere. We were able to characterize crystallographically the structural features of the bis-TPAO complex. The distorted square antiprism [Eu(TPAO)2(H2O)6]Cl3 has been structurally characterized. The compound crystallizes in the orthorhombic crystal system and the space group is, Pccn. Unit cell parameters are a = 35.992(5) Å, b = 10.0915(14) Å, c = 16.638(2) Å, α = β = γ = 90◦ . In addition, in our attempt to develop dual donor system for lanthanide sensitization we have structurally characterized a terbium system consisting of a terpy ligand and a group 11 transition metal complex coordinated simultaneously to a Tb system. The structural feature of the complex shows a distorted antiprismatic Tb(Au(CN)2)3(Terpy)∙4H2O geometry. This complex crystallized in a triclinic system and the space group is, P 1 21/n1 with unit cell parameter of a = 10.6419(17), b = 16.407(3), and c = 24.992(4) Å with α = 90◦ , β = 98.535(5) ◦ , and γ = 90◦ . The studied phosphine oxide and terpy has strong absorbance corresponding to nπ * transition and may act as light harvesting antennae and can subsequently transfer absorbed energy to coordinated Ln(III) cations. Detailed spectral and crystallographic discussions of the compounds are reported in this thesis.

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