Browsing by Subject "Transition metal complexes"

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    Synthetic, structural, and spectroscopic study of luminescent transition metal complexes for use in electronic devices and environmental sensors.
    (2008-11) McGee, Kari Ann
    This thesis describes the synthesis, structural, and spectroscopic study of ruthenium and iridium complexes for use in environmental sensors or electronic devices. Chapters 1-2 discuss studies of ruthenium polypyridyl (pp) complexes used for detection of oxygen gas. In Chapter 1 the variation of the counterion and its affect on the packing structure and subsequent detection of oxygen is discussed. The anion tfpb - (tetrakis(bis-3,5-trifluoromethylphenylborate) worked particularly well and provided the inefficient packing structure with desired channels of open space. In Chapter 2 optically pure metal complexes were explored to alter the packing structure. Both means of creating void space enabled oxygen diffusion to give sensitive and reproducible crystalline oxygen sensors. Chapter 3 describes the dual use of a [Ru(pp) 3 ](tfpb) 2 complex for detection of oxygen and the volatile organic, benzene. The crystalline solid undergoes a reversible vapochromic shift of the emission λ max to higher energy in the presence of benzene. Additionally, in the presence of oxygen the solid exhibits linear Stern-Volmer quenching behavior. This crystalline solid was a practical sensor at low concentrations (0.76%) of benzene vapor. In Chapter 4, the synthesis of new compounds of the general form [( p -cym)Ru(pp)Cl]Cl is discussed. This method allowed the study of a series of Ru(II) complexes, with different polypyridyl and β-diketonate ligands. Modification of the substituent group on the β-diketonate ligand has a pronounced effect on the electronic and electrochemical properties of these complexes. The presence of channels in the crystal structures of two of these molecules as well as the low Ru(III)/Ru(II) redox couple led to their examination as chlorine sensors. In Chapter 5, a selective low-temperature synthesis of the highly desired fac and mer tris-cyclometalated Ir(III) complexes used in OLEDs is discussed. The bis-acetonitrile species, [Ir(C^N) 2 (NCCH 3 ) 2 ]PF 6 , and hydroxy-bridged dimers, [Ir(C^N) 2 (OH)] 2 for two cyclometalating ligands (C^N) were synthesized.The fac-Ir(C^N) 3 and mer -Ir(C^N) 3 complexeswere synthesized at 100 ºC in o -dichlorobenzene from the [Ir(C^N)2(NCCH3)2]PF6 or [Ir(CN) 2 (OH)] 2 complexesrespectively. A mechanism is proposed that may account for the selectivity observed in the formation of these fac-Ir(CN) 3 and mer-Ir(CN) 3 isomers.