Cyclopalladated complexes of 4-aryl-2,1,3-benzothiadiazoles: new emitters in solution at room temperature
Cyclopalladated complexes of 4-aryl-2,1,3-benzothiadiazoles: new emitters in solution at room temperature
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DOI：
10.1039/c1dt10666j
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发表时间：
2011-01-01
影响因子：
4
通讯作者：
Pfeffer, Michel
中科院分区：
文献类型：
--
作者：
Mancilha, Fabiana S.;Barloy, Laurent;Pfeffer, Michel
4-芳基-2，1，3-苯并噻二唑1a-c与乙酸钯在乙酸中环钯化，以良好的产率得到新型二聚配合物2a-c。然后通过在丙酮中与氯化锂反应，然后在二氯甲烷中与吡啶反应，将其转化为单体吡啶-氯-配位的环化络合物3a-c。所有配合物均通过NMR、IR和元素分析进行了表征。配合物2c的X-射线结构表明其为反式构型，而配合物3c的X-射线结构表明吡啶配体和噻唑环之间为相互反式构型。固态漫反射紫外-可见光谱（DRUV）也被应用，以更好地表征配合物在固态下的物理性质。所有络合物通过位于BTD配体中的（LC）-L-1跃迁在约300 nm（λ（1））处呈现强吸收，以及（MLCT）-M-1特征的高于450 nm（λ（2））的额外低能吸收带。该配合物在室温下的溶液中是荧光的，其中可以观察到两个发射带，归因于配体发射的高能带（激发λ（1））和归因于配合物发射的另外的红移的低强度带（激发λ（2））。
The cyclopalladation of the 4-aryl-2,1,3-benzothiadiazoles 1a-c with palladium acetate in acetic acid afforded the novel dimeric complexes 2a-c in good yields. These were then converted into the monomeric pyridine-, chloro-coordinated cyclometallated complexes 3a-c through reaction with lithium chloride in acetone and then pyridine in dichloromethane. All complexes were fully characterized by means of NMR, IR and elemental analysis. The X-ray structure of complex 2c revealed that it presents transoid geometry, whereas the X-ray structure of 3c shows that the pyridine ligand and the thiazole ring are mutually trans. Photophysical properties were investigated by means of UV-Vis absorption and fluorescence emission in solution. Solid-state diffuse reflectance UV-Vis spectra (DRUV) were also applied in order to better characterize the complexes photophysics in the solid state. All complexes present intense absorption at around 300 nm (lambda(1)) via (LC)-L-1 transitions located in BTD ligands, and additional low energy absorption bands, higher than 450 nm (lambda(2)) of (MLCT)-M-1 character. The complexes are fluorescent in solution at room temperature, where two emission bands could be observed, a high energy band (excitation @ lambda(1)) ascribed to the ligand emission and an additional red shifted low intense band (excitation @ lambda(2)) due to the complex emission.