Bis(2-hydroxyethanaminium) biphenyl-4,4′-dicarboxylate

In the title compound, 2C2H8NO+·C14H8O4 2−, the dihedral angle between the benzene rings of the dianion is 9.95 (12)°. In the crystal, the cations and anions are linked via intermolecular O—H⋯O and N—H⋯O hydrogen bonds, generating layers lying parallel to (001).

In the title compound, 2C 2 H 8 NO + ÁC 14 H 8 O 4 2À , the dihedral angle between the benzene rings of the dianion is 9.95 (12) . In the crystal, the cations and anions are linked via intermolecular O-HÁ Á ÁO and N-HÁ Á ÁO hydrogen bonds, generating layers lying parallel to (001).
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LH5226).  (Holman et al., 2001;Plaut et al., 2000;Russell et al., 1997). One of the most important applications, is the use of self-assembly of small molecules with O-H···O, N-H···O and other weaker intermolecular interactions to create one-, two-and three-dimensional networks (Ranganathan et al., 1999;Swift et al., 1998;Zhang et al., 2005). Aromatic acids have attracted our interest because of their importance in crystal engineering and they can form strong directional hydrogen bonds (Bhogala & Nangia, 2003). It is known that ethanolamine (ED) is a good organic base and has hydrogen-bond donor sites. Therefore, combinations of 4,4'-dicarboxyl-biphenyl(BDB) with ethanolamine molecules may be expected to display an interesting network. Herein, we report the crystal structure of the title organic salt (I).
The asymmetric unit of (I) is composed of two independent ED+ cations and one BDB 2dianion ( Fig. 1). The protons of two carboxyl groups from BDB are transferred to the amido groups of ED. The dihedral angle between the two benzene rings of the BDB 2dianion is 9.95 (12) °. In the crystal, dianions and cations are linked via intermolecular O-H···O and N-H···O hydrogen bonds to form a two-dimensional network parallel to (001) which includes R 2 2 (9) rings (Bernstein et al., 1995).
Experimental BDB (0.024 g, 0.01 mmol) and ED (0.012 g, 0.02 mol) were dissolved in hot EtOH/H 2 O (1:1) solution (20 mL). The solution was allowed to cool to room temperature and was evaporated in air for 4 days to give colorless crystals of the title compound (yield: 23%).

Refinement
H atoms bonded to C atoms were positioned geometrically and refined as riding atoms, with C-H = 0.93 -0.97Å and U iso (H) = 1.2U eq (C). H atoms bonded to N and O atoms were refined independently with isotropic displacement parameters.
Figures Fig. 1. The asymmetric unit of the title compound with displacement ellipsoids drawn at the 30% probability level.