Synthesis And Photoinduced Electron Transfer Of Novel Platinum(Ⅱ) And Copper(Ⅰ) Polypyridine Complexes

Photoinduced electron transfer performs one of the most essential and important processes in light-to-chemical energy conversion. Therefore, it has been extensively studied for construction of systems for photoinduced electron transfer. Key goals are to achieve long-lived charge-separation states and high solar-energy conversion efficiency. In this thesis, a series of platinum(II) and copper(I) polypyridine complexes have been designed and synthesized. The photoinduced electron transfers from the complex chromphor to the electron acceptor have been systematically studied and many intersting results are obtained.1. The first platinum(II) chromophore-based dyads [ClPt{C^∧N^∧N(PhMV²⁺)}],[Ph3PPt{C^∧N^∧N(PhMV²⁺)}]⁺,[(μ-dppm)Pt2{C^∧N^∧N(PhMV²⁺)}2]²⁺ and [ClPt{N^∧N^∧N(PhMV²⁺)}]⁺, with the electron acceptor methyl viologen group were synthesized and characterized. The crystal structure of [ClPt{C^∧N^∧N(PhMV²⁺)}] was determined by X-ray crystal analysis.2. Steady and time-resolved spectral investigations suggest that photoinduced intramolecular electron transfers in the platinum(II) dyads with electron acceptor covalently linked are more favorable than the bimolecular electron transfers. These dyads are integrated two-component systems and the interfacial interactions are reduced. Furthermore, no photodegradation was found during the photoinduced electron transfer process for all of these dyads. All these results show the dyads are superior photocatalysts.3. Two copper(I) polypyridine complexes with viologen groups covalently linked [Cu{HC^∧N^∧N(PhMV²⁺)}2]⁺ and [Cu{HC^∧N^∧N(PhMV²⁺)}(PPh₃)₂]⁺ were synthesized. The crystal structure of [Cu{HC^∧N^∧N(PhMV²⁺)}₂]⁺ was confirmed by X-ray crystal analysis.4. Long-lived charge-separated states of the two copper(I) complexes were investigated due to the fifth-coordination of solvent with the Cu(II) center and the lifetime could be tuned by varying the solvent. Even steady-state spectra could monitor the production of photoinduced electron transfer with the electron donor TEOA in the systems. Moreover, copper(I) complexes are inexpensive and less toxic. So these copper(I) complexes have emerged as promising candidates for photocatalysis.