Abstract
A series of novel phosphorescent platinum (II) complexes bearing phosphine ligands were synthesized. Photoluminescence of platinum (II) complexes in solid state are influenced by substituents on phosphine ligands, but the energy gap between HOMO and LUMO isn’t. Tri-(4-flourophenyl) phosphine has the best steric effect for preventing Pt-Pt interaction and π-π interaction to make red shift in photoluminescence. DFT-calculation was measured on several of platinum (II) complexes to discuss the reaction mechanism and the effect of different types of anions. According to DFT-calculation, PtdfppyCNPPh3 has the biggest energy gap between HOMO and LUMO, so I tried to synthesize PtdfppyCNPPh3 which can be a deep blue phosphorescent material in OLED. The synthesis of PtdfppyCNPPh3 was unsuccessful, but fortunately, aggregate complex with high luminescence was obtained. We changed reaction condition to promote the yield of aggregate complexes by self-assembly reaction. These two aggregate complexes have unique parellelogramal structure with Pt-CN-Ag unit, which was the first example of Pt-CN-Ag aggregate complex. In other hand, platinum (IV) complexes were synthesized by oxidative-addition process. While platinum (II) complexes were oxidized to platinum (IV) complexes, MLCT gap will be induced to larger. Hence, photoluminescence of platinum (IV) complexes are blue-shifted than that of platinum (II) complexes. Especially, for PtdfppyacacCH3CN, the complex can emit deep blue phosphorescence at 77 K with wavelength of 437 nm, 465 nm, 497nm in which 437 nm was the shortest wavelength of emission with 2,4-diflourophenyl pyridyl ligand.