Synthesis And Properties Of Some Multiazotic Heterocyclic S-triazine Derivatives

Star-shaped triazine derivatives are very important in organic chemisty and widely applied in the fields of magnetic materials, liguid crystal materials, and organic light emitting materials. These compounds usually have good thermal stability and excellent electro-optical properties because of their particular star-shaped exposure structure. In our research, some star-shaped triazine derivatives were prepared and their thermal and electron-transport properties were investigated.⑴2,4,6-tris(p-formylphenoxy)-1,3,5-triazine was synthesized using cyanuric chloride, p-hydroxybenzaldehyde, and triethylamine as the basic materials, and characterized by FT-IR, NMR spectra and elemental analysis. The synthesis technology was optimized, and the yield was much higher compared with the published methods.⑵Some heterocyclic compounds with active amino-groups were synthesized by traditional method using hydrazine hydrate, formic acid, and carbazole as basic materials. Then these compounds reacted with 2,4,6-tris(p-formylphenoxy)-1,3,5- triazine, and some star-shaped triazine derivatives were obtained. The compounds were characterized by FT-IR, NMR spectra and elemental analysis.⑶The thermal properties of these compounds were investigated by the way of differential scanning calorimetry (DSC) and thermalgravitational analysis (TG-DTG), and the results indicated that all the compounds had good thermal stability with no glass transition process. The four compounds all degraded after melting, and the melting points were 219℃, 150℃, 190℃, 313℃, separately. Furthermore, the results also indicated that the thermal properties of the compounds descended evidently because of the presence of methyl and hydroxymethyl groups, and the thermal property of compound with a hydroxymethyl group was better than compound with a methyl group which might caused by the hydrogen bonding association. The thermal property of compound with carbazole ring was much better than others.⑷The electron-transport properties of the compounds were investigated by the energy band structure parameters which were calculated through UV-visible absorption and cyclic voltammogram. The energy gaps ( E g) of the four compounds were 3.66 eV, 3.56 eV, 3.54 eV, 2.94 eV, separately, and the LUMO energy levels ( E LUMO) were﹣3.97 eV,﹣3.92 eV,﹣3.85 eV,﹣3.98 eV, separately. The LUMO energy levels of electron-transport materials must be below﹣3.0 eV which might indicate that the compounds we had synthesized had a good electron-transport properties. In addition, the LUMO energy levels of compounds with methyl and hydroxymethyl groups were a little lower which might showed us that the properties of compounds were not changed evidently in the presence of functional groups. Furthermore, the property of compound with carbazole ring was closely to others.In this paper, a series of new triazine derivatives with nonplanar, star-shaped structure were synthesized. These compounds, with good stability and excellent electron-transport properties, might have widely applications in the future.