Acta Cryst. (2010). E66, o2656  [ doi:10.1107/S1600536810037748 ]

1-Carboxymethyl-1'-carboxylatomethyl-3,3'-[p-phenylenebis(oxymethylene)]dipyridinium bromide dihydrate

H.-L. Lian and W.-C. Pan

Abstract: In the crystal structure of the title salt, C₂₂H₂₁N₂O₆⁺·Br^-·2H₂O, pairs of betaine molecules are bridged by protons (the bridging proton is disordered), forming strong and symmetrical O-HO hydrogen bonds, leading to an infinite chain along the b axis. The water molecules are linked to the betaine molecule and the bromide ion through O-HO and O-HBr interactions. The central ring, located on an inversion centre, makes dihedral angles of 1.2 (2)° with the outer rings. One of the carboxylic acid groups is deprotonated.

Online 30 September 2010

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