Optical properties of pyrazine derivatives compared with their s-triazine analogs

A series of aryl-substituted pyrazine derivatives, as well as their s-triazine analogues, have been synthesized. For the three-branched compounds, the pyrazine derivatives show strong emission, while its s-triazine analogue TSTA shows too weak emission to be detected. Furthermore, the two-branched pyrazine with para-branching pattern exhibits much higher emission intensity than its analogue which attaches two branches in meta-position. These results indicate great effects of branching pattern on fluorescence intensity for multi-branched compounds with six-membered aromatic center.