Utsuno Mitsuya, Yutaka Tomona, Murata Masaki, Kurihara Masato, Tamai Naoto, Nishihara Hiroshi
Department of Chemistry, School of Science, The University of Tokyo, Hongo, Tokyo, Japan.
Inorg Chem. 2007 Dec 24;46(26):11291-6. doi: 10.1021/ic700953k. Epub 2007 Nov 29.
Anthraquinone-bridged mononuclear and dinuclear complexes, PtCl(AQ-amide-tpy) (1), Pt2Cl2(AQ-amide-tpy2)2 (2), and Pt2Cl2(AQ-eth-tpy2)2 (3), were synthesized and their photochemical properties were investigated. Amide-bound mononuclear complex 1 exhibited only metal-to-ligand charge transfer (MLCT) absorption and emission, whereas dinuclear complex 2 exhibited a low-energy emission around 700 nm at room temperature. Emission lifetime analysis indicated that this emission was originated from the metal-metal-to-ligand charge transfer (MMLCT) excited state, implying the existence of an intramolecular Pt-Pt interaction at the photoexcited state. 3 with rigid ethynylene linkers showed a low-energy absorption around 520 nm (epsilon = approximately 1100 M(-1) cm(-1)) in addition to an 1MLCT absorption, which was ascribed to a 3MLCT absorption from the consideration of the Pt-Pt distance on a geometry-optimized structure. The emission of 3 appeared at 600 nm, which is higher in energy compared with the emission of 2. It is postulated that the restriction of the Pt-Pt distance flexibility in the rigid structure of 3 prevents the significant increase of the Pt-Pt interaction at the excited state.
合成了蒽醌桥连的单核和双核配合物，即PtCl(AQ-酰胺-tpy)（1）、Pt2Cl2(AQ-酰胺-tpy2)2（2）和Pt2Cl2(AQ-乙炔基-tpy2)2（3），并研究了它们的光化学性质。酰胺键合的单核配合物1仅表现出金属到配体的电荷转移（MLCT）吸收和发射，而双核配合物2在室温下在700nm左右表现出低能量发射。发射寿命分析表明，这种发射源于金属-金属到配体的电荷转移（MMLCT）激发态，这意味着在光激发态存在分子内Pt-Pt相互作用。具有刚性乙炔连接体的3除了1MLCT吸收外，在520nm左右还表现出低能量吸收（ε = 约1100 M(-1) cm(-1)），从几何优化结构上的Pt-Pt距离考虑，这归因于3MLCT吸收。3的发射出现在600nm，与2的发射相比能量更高。据推测，3的刚性结构中Pt-Pt距离灵活性的限制阻止了激发态下Pt-Pt相互作用的显著增加。
