Glimsdal Eirik, Dragland Ingunn, Carlsson Marcus, Eliasson Bertil, Melø Thor Bernt, Lindgren Mikael
Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
J Phys Chem A. 2009 Apr 9;113(14):3311-20. doi: 10.1021/jp8083277.
The photophysical properties of a series of platinum(II) acetylide compounds (trans-Pt(PBu(3))(2)(C[triple bond]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 micros 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.
系统研究了一系列铂（II）乙炔化合物（反式-Pt(PBu(3))(2)(C≡C-R)(2)）的光物理性质，其中R基团由通过乙炔基连接在一起的两个或三个芳环（苯基、苯基/噻吩基、苯基/三唑基）组成。报道了四种结构相似的新化合物，其具有：（i）配体中的联噻吩单元，（ii）芳环配体上的甲基或（iii）甲氧基取代基，这些取代基促进了分子长轴方向上更扭曲的构象，以及（iv）具有两种不同的炔基芳基配体，导致相对于光活性金属离子中心的不对称取代。光谱研究包括光吸收、光谱和时间分辨发光以及瞬态吸收光谱。300至420nm之间的基态紫外吸收产生了量子效率在0.1-1%范围内的荧光，并有效地系间窜越到三重态。在抽空氧气的样品中，磷光衰减时间为10-500微秒量级。三重态还导致在400至800nm之间有强烈的宽带三重态-三重态吸收。发现具有不对称取代的配合物填充了两种结构和能量不同的三重态。
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