Design, Synthesis, And Properties Of Functional Molecules Based On Porphyrin And Pyrrole

Cyclic porphyrinic arrays have attracted much attention for their potential applications in models of artificial photosynthetic antenna, optoelectronic devices, sensors, photovoltaic devices and non-linear optical(NLO) materials. Peripherally metalated porphyrins should offer a scaffold to investigate electronic and steric effects of the inner metal and porphyrin core onto the outer metal. Such effects influence molecular physical and chemical properties such as magnetism, photophysics, and reactivity in metal-catalyzed reactions.In this thesis, β-to-β 2,5-pyrrolylene-bridged cyclic porphyrin dimers, trimers and earring porphyrin were synthesized by Suzuki-Miyaura cross-coupling reaction. Further exploration of the photophysical and electrochemical propertiess of these compounds provided relatively ideal results. The key studies are listed below.(1) According to literature procedures, β-borylated porphyrin and α-borylpyrrole were synthesized via highly regioselective Ir-catalyzed C-H bond activation in high yields. Later, treatment of β-borylated porphyrin with CuBr2 in THF/H2 O or CuBr/NBS in toluene/DMF affords β-bromoporphyrins.(2) β-to-β 2,5-pyrrolylene bridged porphyriyn cyclic dimers, trimers and non-cyclic pyrrolylene bridged porphyrin were prepared by Suzuki-Miyuara cross-coupling of β-brominated porphyrin and α-borylpyrrole. These compounds were characterized by 1H NMR, mass spectra. Two molecular structures of these compounds were confirmed by crystal X-ray diffraction techniques. Their photophysical properties of these compounds were studied by UV/Vis absorption spectra, fluorescence emission spectra. Their electrochemical properties were studied by cyclic voltammetry. The optical and electrochemical properties of the pyrrolylene bridged cyclic porphyrin array were different from those non-cyclic porphyrins, such as broader Soret bands and Q-bands, small reduced fluorescence quantum yields and electrochemical HOMOLUMO gap. Those results demonstrate that the pyrrolylene bridged cyclic porphyrin oligomers display larger electronic interactions than non-cyclic arrays.(3) Earring porphyrins were obtained by Suzuki-Miyaura reaction of β-brominated porphyrin and bis-(boryl)tripyrrane. Treatment of the earring porphyrins with Pd(OAc)2, Cu(OAc)2 and Ni(OAc)2 resulted in facile metalation to afford Pd(II), Cu(II) and Ni(II) complex, respectively. These compounds were characterized by 1H NMR, and one molecular structure was confirmed by X-ray diffraction analysis. The photophysical of these compounds were examined by UV/Vis absorption spectra. These absorption of these earring porphyrin derivatives extended into near-IR region, these features are particularly advantageous for potential applications in optical devices working in the near-IR region.