| abstract |
The present invention relates to the use of a compound having formula (I) as a fluorescent chromophore: Wherein: A 1 is -N- or -C (Y 1 ) -; A 2 is -N- or -C (Y 2 ) -; A 3 is -N- or -C (Y 3 ) -; A 4 is -N- or -C (Y 4 ) -; At least one of A 1 , A 2 , A 3 and A 4 represents -N-; X 1 is -N- or -C (Y 5 ) -; X 2 is -N- or -C (Y 6 ) -; X 3 is -N- or -C (Y 7 ) -; Y 1 , Y 2 , Y 3 , Y 4 , Y 5 , Y 6 and Y 7 are independently selected from the group consisting of H, electron-donating groups and electron-withdrawing groups. |