Organic Amorphous Material N,N,N,N'-tetraaryl(Ar_2~1Ar_2~2)-1,1'-1,1'-biphenylk-4,4'-diamine

摘要

A series of N,N,N,N'-tetraaryl(Ar_2~1Ar_2~2)-1,1'-biphenyl-4,4'-diamine were synthesized by the Pd(O) catalyzed C-N bond formation methodology. The physical properties, including glass transition temperature (Tg), melting point (Mp) and oxidation potential were measured. For Ar~1 = 2-naphthyl and Ar~2 = 3-toly (4f) and Ar~2 = 3-ethylphenyl (4h), the DSC charats indicate that theyhave Tg, but no observale Mp. These two compounds are amorphous in solid state. The X-ray powder diffraction pattern of 4f further confirmed that it is truly amorphous throughout the temperature range in which it is solid. Therefore, we have demonstrated that a low molecular weight organic solid can be amorphous. This is an important aspect in the preparation of morphologically stable amorphous thin film. Other compounds with Ar~1 = Ph, 1-naphthyl while Ar~2 = 3-toly or 3-ethylphenyl are normal compounds with both Tg and Mp when prepared in their glassy state by rapid cooling of their melt. The oxidation potentials for compounds with Ar~1 = 1-naphthyl and 2-naphthyl and identical Ar~2 are exactly the same. The molecular structural features must be important factors for an organic solid to be in the amorphous state.