Synthesis And Properties Of Novel Organic Electroluminescent Materials Base On Metal-organic Coordination Polymers

Metal-organic complexes play an important role in the research of organic electroluminescent materials. Among the ligands reported, N,O-containing ligands, such as schiff bases and hydrobenzothiazoles, have attracted extensive attention in researches. Herein, we hope to report a series of novel metal-organic coordination polymers based on bisalicylaldehyde derivatives as organic electroluminescent materials.Three kinds of bisalicylaldehydes were prepared from 4,4'-biphenol ,salicylaldehyde and bisphenol A.And then kinds of substitutes were introduced into the bisalicylaldehydes. Series of novel ligands, such as Schiff bases and hydrobenzothiazoles, were synthesized from substituded bisalicylaldehydes backbone, then coordinated with Zinc(II) to give corresponding coordination polymers. The ligands and complexes with linker C(CH3)2 which were synthesized from bisphenol A had the best solubility.The thermal properties were detected by TG test. The decomposition temperature of Schiff base Zinc coordination polymers was 400 oC. That of hydrobenzothiazole-Zinc coordination polymers was high to 520 oC.The fluorescence emission peaks of Schiff base-Zinc coordination polymers were between 490~515 nm and the quantum yields were between 0.8%~7.6%. The fluorescence emission peaks of hydrobenzothiazole ligands were between 540~580 nm while the emission peaks of hydro- benzothiazole-Zinc coordination polymers had a blue-shift and located at 470~490 nm. The quantum yields of the hydrobenzothiazole ligands were between 0.8%~2.5% while the quantum yields of complexes were between 2.3%~12.4%. A red-shift and enhanced emission spectrum were brought with the introduction of conjugated substitutes to the ligands and homologous comlpexes.The crystal structure of hydrobenzothiazole ligand 4c was analyzed. The wide conjugated and plane structure explained the reason of the strong emission of hydrobenzothiazoles. The CV analysis showed the Schiff base-Zinc and hydrobenzothiazole-Zinc coordination polymers have suitable energy-band structures. Thus the compounds synthesized here can become promising organic electroluminescent materials.