| Popis: |
This Thesis is concerned with the preparation and study of photo active cyanometallate complexes. Chapters 2 to 4 focus on the photophysical and structural properties of these complexes when involved in hydrogen-bonded or halogenbonded supramolecular assemblies. The last two Chapters mainly deal with the synthesis of some new polynuclear cyanometallate complexes of osmium(II) and ruthenium(II) and report on their characterisation. Chapter 1: provides an introduction to supramolecular photochemistry of Ru(polypyridyl) complexes. The emphasis is on [Ru(bipy)(CN)4f', with a quick review of its main characteristics. Chapter 2: analyses the H-bonding interaction in solution (lH NMR, UV-Vis spectroscopy) and solid state between various cyanometallate complexes and the photoactive compound [Ru(bipY)2(H2biim)]2+. Strong charge-assisted H-bonded assemblies are formed in solid state and solution, and one assembly exhibits oxidative photo-induce electron transfer. Chapter 3: reports on the serendipitous isolation and structural characterisation of a ruthenium cyanide-bridged dinuclear complex. Chapter 4: describes the study of halogen-bonding interaction between [Ru(bipy)(CN)4f' and a series of halogen substituted pyridinium ions. Formation of halogen bonding is monitored by spectroscopic and X-ray characterisation. Halogen bonding is found to control association of the components in solid state, whereas in solution electrostatic interactions prevail. Chapter 5: deals with the preparation and structural and photophysical characterisations of a series of novel mono- and dinuclear osmium complexes, of the type [Os(ll-diimine)(CN)4f' and [Os2(Il-diimine)(CN)s]4-. In one such dinuclear complex, both electrochemical and TRlR data prove that electronic communication between the metal centres is solvent dependent. Chapter 6: represents an early stage in the development of a series of highnuclearity dendrimeric structures based on cyanometallate systems. Synthesis and preliminary characterisation of one trinuclear and one tetranuclear complex based on a [Ru(bpm)3]2+ core with peripheral {Ru(CN)4} 2- units is reported. |
