Orientation and Polarized Optical Emission Properties of Platinum(II) Complexes in Smectic Liquid Crystals
Orientation and Polarized Optical Emission Properties of Platinum(II) Complexes in Smectic Liquid Crystals
复制标题
DOI：
10.1002/ejic.201201388
复制
发表时间：
2013-04
影响因子：
2.3
通讯作者：
Takeshi Sato;H. Awano;H. Katagiri;Yong‐Jin Pu;Tatsuhiro Takahashi;K. Yonetake
中科院分区：
文献类型：
--
作者：
Takeshi Sato;H. Awano;H. Katagiri;Yong‐Jin Pu;Tatsuhiro Takahashi;K. Yonetake
我们制备了一系列具有棒状配体和近晶液晶（LCs）的铂配合物，以表现出极化磷光。具有长烷基和烷氧基链的Pt配合物“12F2PPyO8”[2-（4 ' -十二烷基-5 ',6 ' -二氟苯基）-5-十二烷基-5 ',6 ' -二氟苯基)-5-十二烷基-氧基吡啶- n，C2 ']和“12F2PPyO12”[2-（4 ' -十二烷基-5 ',6 ' -二氟苯基）-5-十二烷基-氧基吡啶- n，C2 ']的配体表现为smtic A （SmA）相，而与LC配体的Pt配合物没有明显的液晶性。具有长柔性链的宿主lc1 -（4-丁基-2,3-二氟苯基）-4-（反式-4-戊基环己基）苯（4F2PPCH5）和2-（2,3-二氟-4-己基苯基）-6-辛基萘（6F2PNaO8）表现出较宽的SmA相温度范围。铂配合物/Sm LC混合物在摩擦聚酰亚胺衬底上或通过施加磁场定向。在Sm - LC温度范围内，磁取向样品的取向系数大于0.6。取向样品表现出垂直于取向方向的单体态和准分子态的偏振光发射。这表明Pt配合物的跃迁偶极矩是从配体向Pt原子取向的。具有长烷基和烷氧基链的棒状配体的铂配合物和具有此类链的寄主Sm LC更容易获得高阶参数并产生高偏振光发射。在混合物中，SmA相中单体和准分子的极化比分别约为2.5 ~ 2.9和4.6 ~ 5.4。
We have prepared a series of platinum complexes with a rodlike ligand and smectic (Sm) liquid crystals (LCs) to demonstrate polarized phosphorescence. The ligands for the Pt complexes “12F2PPyO8” [2-(4′-dodecyl-5′,6′-difluorophenyl)-5-octyloxypyridinato-N,C2′] and “12F2PPyO12” [2-(4′-dodecyl-5′,6′-difluorophenyl)-5-dodecyloxypyridinato-N,C2′] with long alkyl and alkoxy chains exhibited the Smectic A (SmA) phase, however no liquid crystallinity was evident in Pt complexes with LC ligands. The host LCs 1-(4-butyl-2,3-difluoro-phenyl)-4-(trans-4-pentylcyclohexyl)benzene (4F2PPCH5) and 2-(2,3-difluoro-4-hexylphenyl)-6-octyloxynaphthalene (6F2PNaO8) with long flexible chains showed wide SmA phase temperature ranges. Pt complex/Sm LC mixtures were oriented on rubbed polyimide substrates or by applying a magnetic field. The orientation coefficients of the magneto-oriented samples were recorded to be over 0.6 in the Sm LC temperature range. The oriented samples exhibited polarized optical emissions assigned to the monomer and excimer states, which were perpendicular to the orientation direction. This indicates that the transition dipole moment of the Pt complex is oriented from the ligand to the Pt atom. Pt complexes with rodlike ligands with long alkyl and alkoxy chains and host Sm LC with such chains are much more likely to obtain high order parameters and generate highly polarized optical emissions. In the mixtures, the polarization ratios of the monomer and excimer in the SmA phase were estimated to be approximately 2.5–2.9 and 4.6–5.4, respectively.