[pi]-metal complexes of i-propyldinaphthoporphycene



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Porphycenes have attracted attention for their ability to stabilize complexes with a wide range of metal cations. Coordination compounds of these macrocycles are endowed with of specific chemical, optical, electronic, spectroscopic and photochemical properties,1-8 such as, strong absoptions in the red region of the UV-vis spectrum. These characteristics have been used in the study of protein mimicry,9, 10 photodynamic therapy (PDT)11-16 and materials chemistry17, 18 The fusion of bipyrrolic entities with aromatic rings could led to a change in the photophysical properties of porphycenes, and could give rise to nonlinear optical (NLO) behavior.19 Taken in concert, these possibilities provides an incentive to study metal complexes of new porphycenes. With that goal in mind, presented here is the synthesis and the spectroscopic and voltamperometric analyses of four metollocene complexes of a relatively new annulated porphycenes, namely i-propyldinaphthoporphycene. Chapter 1 of this thesis provides a brief introduction into porphycenes and porphyrins as well as complexes prepared from these macrocycles. Because it relates more closely to the research described in this thesis, the emphasis will be on peripherally substituted and directly π-metallated porphyrin-like macrocycles. Annulated porphycenes and their metal complexes display geometric and optical features that differ from those of normal porphycenes. Chapter 2 details the coordination compounds of annulated porphycenes, as well as some of their optical and redox features. This chapter also summarizes the current synthesis of dinaphthoporphycenes, while detailing efforts by other authors to coordinate transition metals to dinaphthoporphycenes, which culminated in the preparation of the first nickel(II) complex known so far with this ligand. It was recently found that the electronic properties of porphycenes change from those of an electron donor to those of an electron acceptor when the RuCp* (Cp*: pentamethylcyclopentadienyl) fragment is coordinated to the “π-face” of the macrocycle. This finding, discovered using so-called etioporphycenes, motivated the author to explore the metal complexation chemistry of i-porpyldinaphthoporphycene. This led to the synthesis of four metalloporphycenes are described in Chapter 3. Here, the coordination of the [M(Cp*)]n+ (M = Ru, Ir and Rh) fragments to the π-electron framework was established by analytical, and structural means. Thus, this chapter provides of a description of the spectroscopic, structural and voltamperometric features of these complexes.