1 K66 [4,5,6,7-tetrabromo-2-(dimethylamino)-1h-benzimidazol-1-yl]acetic acid 1.000 2 K68 (4,5,6,7-tetrabromo-1h-benzimidazol-1-yl)acetic acid 0.850 3 K25 4,5,6,7-tetrabromo-N,N-dimethyl-1h-benzimidazol-2-amine 0.800