Patent ID: 7014981

Claim:
A benzoindole styryl compound, which has the following chemical structure: where R 1 is CH 2 C 6 H 4 CO 2 R 6 , R 6 being an alkyl or fluorinated alkyl group; R 2 and R 3 are selected from the group consisting of hydrogen atoms, alkyl groups containing one to eight carbons (C 1-8 ), alkyl-oxygen groups containing one to eight carbons, alkyl-ester groups (—CO 2 R 8 ) containing one to eight carbons, and a pyrrolidine ring formed by connecting R 2 and R 3 , a julolidine ring formed by one of R 2 and R 3 to benzene ring, R 8 being an aklyl or fluorinated alkyl group; R 4 and R 5 are selected the group consisting of hydrogen atoms, alkyl groups with one to eight carbons (C 1-8 ), trifluoromethyl groups, alkyl-oxygen group, carboxyl groups, nitric groups, amide groups (CONR 9 R 10 ), sulfonic groups, SO 3 R 11 , alkyl-ester groups with one to eight carbons (C 1-8 ), and halide ions (Y − , each of R 9 , R10 and R 11 being hydrogen or an aklyl group; wherein the choice of Y − needs to match R 1 and Y − is selected from the group consisting of (TCNQ − ) n (tetracyano-p-quinodimethane), (TCNE − ) n (tetracyanoethylene) (n=0, 1), CIO 4 —, SbF 6 —, PF 6 —, BF 4 and halide ions.