以2-苯基吡啶为主配体、以氟修饰的吡啶-2-甲酸为辅助配体合成出一系列环金属中性铱配合物。产物结构通过核磁及质谱进行了确认, 对其光物理性能研究表明, 这些配合物的发光波长在498～516 nm之间, 属于绿光发射。没有氟取代的配合物Ir1量子效率最高, 达到32%, 而由于2位氟取代的位阻影响Ir4的量子效率最低只有6%, 其他氟取代配合物的量子效率在13%～16%之间。引入氟原子后配合物的氧化电位都有所增加, 氧化电位由511 mV增加到547～574 mV 之间。热稳定性也在氟取代后增加, 由142 ℃提高到187～380 ℃之间, Ir4提高的最少, 为187 ℃。应用于电致化学发光时, 除Ir4外, 氟取代都能增加其电致化学发光强度, 由332增加到333～370之间。而配合物Ir4的发光强度只有203。以上结果表明氟取代的效果跟位置有很大关系, 2位氟取代由于位阻效应, 使配合物的量子效率及稳定性都有不利影响, 而其他位置的取代则能提高配合物的这些性能。该研究结果对设计开发综合性能优异的发光材料具有借鉴意义。

A series of neutral cyclometalated iridium(Ⅲ) complexes(Ir1-Ir5), which containing 2-phenylpyridine main ligand and fluorinated picolinic acid ancillary ligands, were synthesized with main ligand of 2-phenylpyridine and ancillary ligand of 2-pyridine carboxylic acid. The structures of the complexes were confirmed by the NMR and mass spectroscopies. All these complexes displayed intense green phosphorescent emission with the emission maximum between 498 nm and 516 nm. The quantum efficiency of reference complex Ir1 is 32.0%. Due to the influence of the 2-position fluorine substituent, complex Ir4 has the lowest quantum efficiency of 6.0%. The quantum efficiency of other fluorinated complexes are between 13.0% and 16.0%. Compared with the reference complex Ir1, the oxidation potential of fluorinated complexes increased from 511 mV to 547-574 mV and the thermal stability enhanced from 142 ℃ to 187-380 ℃. The thermal stability increase of Ir4 is the minimum(187 ℃). The ECL intensity of reference complex Ir1 was 332. Except Ir4, the ECL intensity of complexes Ir2-Ir5 is higher than reference complex Ir1, which is between 333 and 370. Complex Ir4 has the lowest ECL intensity of 203. All these results show the influence of fluorine substituent is related to the substituent positions in picolinic acid. The 2-position fluoro-substitution can reduce the quantum efficiency and thermal stability because of the steric effect. Relatively, fluoro-substitution on other positions can enhance these two performances. This research can be used as a reference in the design and development of efficient luminescent materials.