Light-induced dynamics in photoactive metal complexes with secondary chromophores
The present thesis is concerned with the photophysical characterization of mono- and multimetallic photoactive transition metal complexes and corresponding dyads and triads with functional organic chromophores. In particular, electronic interactions in ground and excited states between the constituents in multichromophoric compounds are analyzed. Light-induced dynamics in the given systems are probed using femtosecond transient absorption spectroscopy in order to identify and detail energy and electron transfer processes. The major portion of this thesis treats bis(tridentate) complexes based on 4-substituted 2,2 :6 ,2 -terpyridines and Fe(II), Ru(II), Os(II) and Ir(III) central ions. Such compounds are studied as potential building blocks for hierarchic coordination oligomers. In this context, dyads with Ru(II) central ions and fullerene units are analyzed in dependence of the size of bridging chromophore and linker units. With respect to multimetallic complexes, energy transfer processes between Ru(II) and Os(II) and Fe(II) complex fragments are studied. In a trinuclear Ru(II)-Fe(II)-Ru(II) complex exposed to high excitation fluence kinetically hindered energy transfer is observed. Keywords: Ruthenium(II), Iron(II), Osmium(II), Iridium(III), transition metal complexes, 2,2 :6 ,2 -terpyridine, 2,6-di(quinolin-8-yl)pyridine, time-resolved spectroscopy, transient absorption, multichromophoric compounds, dual emission, excitation energy transfer.
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