organic heterocyclic compound cyanine dye Cy5 dye 1 297.13917 297.373 cyanine5 dye CHEBI:37989 cyanine5 dyes C21H17N2R2 cyanine 5 dyes Cy5 Cy5 dyes cyanine 5 dye chebi_ontology cyanine dye 5 [1*][N+]1=C(C([H])=CC([H])=CC([H])=C2Cc3ccccc3N2[2*])Cc2ccccc21