Browsing by Subject "Ruthenium"
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Item Synthesis and characterization of ruthenium (II) tetraphenylporphyrin with redox active axial ligands for molecular wires(2016-05) Fathi Rasekh, MahtabFour new ruthenium(II) tetraphenylporphyrin with redox active axially coordinated ligands including two new heterotrinuclear Fe-Ru-Fe complexes of the ruthenium(II) tetraphenylporphyrin axially coordinated with a pair of isocyanoferrocene ((FcNC)2RuTPP) or 1,1'-diisocyanoferrocene (([C5H4NC]2Fe)2RuTPP) ligands [Fc = ferrocenyl, TPP = 5,10,15,20-tetraphenylporphyrinato(2-) anion], and two new isocyanoazulene containing complexes (2-CNAz)2RuTPP ( 2-CNAz = 2-isocyanoazulene) and (6-CNAz)2RuTPP ( 6-CNAz = 6-isocyanoazulene) were synthesized and characterized by UV-vis, MCD, NMR, and FTIR spectroscopies as well as by electrospray ionization mass spectrometry and single crystal X-ray diffraction. Isolation of insoluble polymeric {([C5H4NC]2Fe)RuTPP}n molecular wires was also achieved for the first time. The redox properties of the new trinuclear (FcNC)2RuTPP and ([C5H4NC]2Fe)2RuTPP complexes were probed using electrochemical (CV and DPV), spectroelectrochemical, and chemical oxidation methods and correlated to those of the bis(tert-butylisocyano)ruthenium(II) tetraphenylporphyrin reference compound, (t-BuNC)2RuTPP, as well as (2-CNAz)2RuTPP and (6-CNAz)2RuTPP complexes. In all cases, the first oxidation process was attributed to the reversible oxidation of the RuII center. The second and third reversible oxidation processes in (FcNC)2RuTPP are separated by ~100 mV and were assigned to two single-electron FeII/FeIII couples suggesting a weak long-range iron-iron coupling in this complex. Electrochemical data acquired for ([C5H4NC]2Fe)2RuTPP complex are complicated by the interaction between the axial 1-1,1'-diisocyanoferrocene ligand and the electrode surface as well as by axial ligand dissociation in solution. Spectroelectrochemical and chemical oxidation methods were used to elucidate spectroscopic signatures of the [(RCN)2RuTPP]n+ species in solution. In both (2-CNAz)2RuTPP and (6-CNAz)2RuTPP complexes, the first oxidation process was attributed to the reversible oxidation of RuII center and the second oxidation process was assigned to the reversible oxidation of porphyrin core. The third and fourth irreversible processes were assigned to the oxidation of two isocyanoazulene axially coordinated ligands. DFT and TDDFT calculations aided in correlating spectroscopic and redox properties of complexes with their electronic structures.Item Synthetic, structural, and spectroscopic study of luminescent transition metal complexes for use in electronic devices and environmental sensors.(2008-11) McGee, Kari AnnThis 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.