Triplet Excited States of Some Thiophene and Triazole Substituted Platinum(II) Acetylide Chromophores
Triplet Excited States of Some Thiophene and Triazole Substituted Platinum(II) Acetylide Chromophores
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DOI：
10.1021/jp8083277
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发表时间：
2009-04-09
影响因子：
2.9
通讯作者：
Lindgren, Mikael
中科院分区：
文献类型：
--
作者：
Glimsdal, Eirik;Dragland, Ingunn;Lindgren, Mikael
系统地研究了一系列由两个或三个芳基环（苯基、苯基/噻吩基、苯基/三唑基）与乙炔基相连的乙炔化铂（II）化合物trans-Pt（PBu（3））（2）（C-C-R）（2）的物理性质。报道了四种新的结构相似的化合物：（i）在配体中的联噻吩单元，（ii）在芳环配体上的甲基或甲氧基取代基，其促进沿着分子的长轴沿着更扭曲的构象，以及（iv）具有两种不同的炔基芳基配体，其引起相对于光活性金属离子中心的不对称取代。光谱学研究包括光吸收、光谱和时间分辨发光以及瞬态吸收光谱。在300和420 nm之间的基态UV吸收产生荧光，量子效率在0.1-1%的范围内，并且有效的系间跃迁到三重态。磷光衰减时间在10-500 μ s的顺序在氧抽空的样品。三重态还导致在400和800 nm之间的强宽带三重态-三重态吸收。发现具有不对称取代的配合物具有两个不同结构和能量的三重态。
The photophysical properties of a series of platinum(II) acetylide compounds (trans-Pt(PBu(3))(2)(C C-R)(2)) with the R group consisting of two or three aryl rings (phenyl, phenyl/thiophenyl, phenyl/triazolyl) linked together with ethynyl groups were systematically investigated. Four new structurally similar compounds are reported with: (i) a bithiophene unit in the ligands, (ii) methyl or (iii) methoxy substituents on the aryl ring ligands that promote a more twisted conformation along the long axis of the molecule, and (iv) with two different alkynylaryl ligands giving rise to an asymmetric substitution with respect to the photoactive metal ion center. The spectroscopic studies include optical absorption, spectrally and time-resolved luminescence, as well as transient absorption spectra. The ground-state UV absorption between 300 and 420 nm gave rise to fluorescence with quantum efficiencies in the range of 0.1-1% and efficient intersystem crossing to triplet states. Phosphorescence decay times were in the order of 10-500 mu s in oxygen-evacuated samples. The triplet states also lead to strong broadband triplet-triplet absorption between 400 and 800 nm. The complex with asymmetric Substitution was found to populate two triplet states of different structure and energy.