Synthesis, Photophysics Properties Of The Complexes Of Iridium And Europium And Eu(Ⅲ)-coupled Graphene Oxide

Phosphorescent iridium(III) complexes have been intensively studied for more than 10 years because of their remarkable photophysical properties and various optoelectronic applications.To date, they have been widely applied in organic light-emitting diodes(OLEDs), light-emitting electrochemical cells, chemosensors and bioimaging. Considerable efforts have been devoted to synthesis of high performance neutral and cationic iridium(III) complexes with tunable and improved phosphorescent properties through the proper choice of the coordinated ligands.Organic light-emitting diodes(OLEDs) have been intensively studied throughout the world owing to their potential application in the next generation of full-color flat panel displays. Organic and polymeric electroluminescence(EL) across the whole visible region from blue to red has been demonstrated, and the efficiency, brightness, and device lifetime are rapidly approaching commercial target figures. However, it is difficult to achieve pure emission colors from small organic molecules or conjugated polymers. Because of the high pure brightness, monochrome characteristics and chemical environment stability, electroluminescent Eu3+ complexes shows great prospects.Graphene is a 2D single planar sheet of sp2-hybridized atoms with remarkable electronic, mechanical and thermal properties. Since its discovery, graphene has attracted enormous research interest in scientific communit ies.Graphene oxide(GO), which contains a range of reactive oxygen functional groups, is strongly hydrophilic and water soluble, and it can also serve as a substrate for graphene-based materials using known carbon surface chemistry. Futhermore, GO has been observed to exhibit weak luminescence. For imaging GO with visible-light emissions and for convenient applications of GO in the fields of immune recognition and therapeutics, neuroscience research and tissue engineering, and cancer diagnosis and treatment just like carbon nanotubes, researchers have tried to modify GO with fluorescent materials. Traditional organic fluorescent dyes were employed to prepare fluorescent GO. However, the organic fluorescent groups exhibited a shorter life expectancy. It limits the application of GO in these fields. So we linked the Eu(III) complexes and graphene oxide with covalent, resulting in a new functional nano-materials.The compounds not only have the advantages of rare earth fluorescent complexes, but also show the strong hydrophilicity and biocompatibility of graphene oxide(GO).Therefore, the article content is mainly from the following three aspects:(1)We have designed and synthesized a series of pyrazine derivatives and quetiapine, and synthesized the corresponding iridium complexes with acetylacetone(acac) and 1, 3-diphenyl-1,3-propylene ketone(dbm) as the ligand. All the compounds were detected by NMR, MS and elemental analysis. At the same time the UV-visible, fluorescence and electrochemical test of the the compounds were investigated in methylene chloride solution.By changing the conjugation of the primary ligand and vice ligand, the luminescence properties of the complexes were improved and we achieved the effective control of yellow to red.(2)We have designed and synthesized a series of phenanthroline derivatives, and synthesized the four corresponding europium complexes with the trifluoroacetyl thiophene acetone(tta) as the ligand. All the compounds were detected by NMR, MS and elemental analysis. At the same time the UV-visible and fluorescence test of the the compounds were investigated in ethanol solution. We introduced the groups of amino(-NH2), hydroxyl(-OH), carboxyl(-COOH) and nitro(-NO2) in the phenanthroline derivatives.The good carrier mobility of these group well improved the carrier mobility of the ligand and improved the electrioluminescence properties of the europium complexes.(3)By amidation reaction of the carboxyl group of graphene oxide and the amino group of phenanthroline derivatives,we got Eu(III)/graphene oxide compounds. The complexes were detected by IR, XPS and TEM. At the same time the UV-visible and fluorescence test of the the compounds were investigated in ethanol solution. The experiment results show that the compounds have strong luminescence, and enhanced the fluorescence properties of graphene oxide.