Design, Synthesis And Characterization Of Novel 2, 2’-bipyridine Derivatives Containing Intramolecular Hydrogen Bond And Their Ruthenium Complexes

The donor side of PSⅡ（PhotosystemⅡ） is the most important part of PSⅡ, which supply raw materials and energy for sustaining all lifeforms on earth. In order to construct an artificial photosystem to realize light-induced water oxidation, substantial efforts have been paid to mimic the structure and function of the donor side of PSⅡ. Proton coupled electron transfer （PCET） process is a common but significant process in nature. It have been proved that the electron transfer process from oxygen evolving center to the photosensitizer P680+in PSⅡis also a PECT process. But the mechanism has not been clear until now. Recently, many model systems was established for the investigation of the PECT process in PSⅡ. In this thesis, two mononuclear Ru（Ⅱ） complexes containing strong hydrogen bonds were designed and synthesized, aiming for mimicking the electron transfer process from Tyrz to P680+ assisted by a vicinal histidine His190.First, ligands 4, 6 and 7 were prepared upon the introduction of the phenol or 2-naphthanol group to the ligand 2, 2’ -bipyridine. Their structures were characterized by IR, 1H NMR, MS and elemental analysis. The strong intramolecular hydrogen bonds （formed from the hydrogen of the phenolic OH or naphtholic OH with the bridging C=N nitrogen or the bridging diazo nitrogen） was observed by 1H NMR and X-ray crystallography.Complexes 9 and 11 was obtained through the reaction of ligand 7 with cis-[Ru（bpy）₂]Cl₂·2H₂O and [Ru（phen）₂]Cl₂·2H₂O respectively. Their structures were characterized by IR, 1H NMR, MS and elemental analysis. The introduction of diazo-2-naphthol group makes the MLCT band of complex 9 redshifted with 49 nm compared with the reference complex [Ru（bpy）₃]（PF₆）₂. When using two phenanthroline ligands instead of 2, 2’ -bipyridine ligands, complex 11 was obtained. Its MLCT band slightly blueshifted compared with complex 9.Compared with the reference complex [Ru（bpy）₃]（PF₆）₂, no emission was found for complex 9 and 11. It means that the 3MLCT bands of complex 9 and 11 were quenched by an energy transfer or an electron transfer process after the introduction of diazo-2-naphthol group. We hope that the existence of the strong intromolecular bond decrease the oxidative potential of the naphthanolic OH and promote the intromolecular electron transfer speed from the naphthanolic OH to the Ru²⁺ center. In the future work, we will further investigate the PECT process in complex 9 and 11 by electrochemical, nanosecond laser flash photolysis and theory calculation etc.