Rachford Aaron A, Hua Fei, Adams Christopher J, Castellano Felix N
Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, USA.
Dalton Trans. 2009 May 28(20):3950-4. doi: 10.1039/b818177b. Epub 2009 Feb 12.
The synthesis and subsequent photophysical investigation of [Pt(mesBIAN)(tda)], where mesBIAN is bis(mesitylimino)acenaphthene and tda is tolan-2,2'-diacetylide, reveal excited-state characteristics best described as triplet charge transfer ((3)CT) in nature upon visible light excitation. Large ground-state dipole moments are apparent as the absorption spectrum dramatically red-shifts with decreasing solvent polarity. The (3)CT excited state is significantly lower in energy than the ligand-centered (3)tda excited-state, as confirmed by steady-state and time-resolved techniques. Singlet oxygen sensitization studies demonstrate that (1)O(2) production occurs by diffusive quenching from the photo-excited (3)CT state (Phi(Delta) = 0.24, lambda(max) approximately 1270 nm) in oxygen-saturated dichloromethane.
[Pt(mesBIAN)(tda)]的合成及其后续光物理研究表明，在可见光激发下，其激发态特性本质上最适合描述为三重态电荷转移((3)CT)。其中mesBIAN为双(均三甲苯基亚氨基)苊，tda为二乙炔基苯。随着溶剂极性降低，吸收光谱发生显著红移，表明存在较大的基态偶极矩。稳态和时间分辨技术证实，(3)CT激发态的能量明显低于配体中心(3)tda激发态。单线态氧敏化研究表明，在氧气饱和的二氯甲烷中，(1)O(2)是通过光激发(3)CT态的扩散猝灭产生的(Phi(Delta)=0.24，lambda(max)约为1270nm)。
