Bis(benzyltrimethylammonium) bis[(4SR,12SR,18RS,26RS)-4,18,26-trihydroxy-12-oxido-13,17-dioxaheptacyclo[14.10.0.0^3,14.0^4,12.0^6,11.0^18,26.0^19,24]hexacosa-1,3(14),6,8,10,15,19,21,23-nonaene-5,25-dione] sesquihydrate: Dimeric structure formation via [O-H-O]^- negative charge-assisted hydrogen bonds (-CAHB) with benzyltrimethylammonium counter-ions

The reaction between bis-ninhydrin resorcinol and benzyltrimethylammonium fluoride in ethanol has produced the title compound, 2C₁₀H₁₆N⁺·2C₂₄H₁₃O₈ ^-·1.5H2O, which contains a unique centrosymmetric supramolecular dimeric entity, where two deprotonated ligands are held together via two strong and short [O⋯O = 2.4395(13)Å] [O-H-O]^- bonds of the type negative charge-assisted hydrogen bonds (-CAHB). The central aromatic rings of the ligands create parallel-displaced π-π stacking at an interplanar distance of 3.381(1)Å, which helps stabilize the dimer. In the crystal, two symmetry-related solvent water molecules with a site occupancy of 0.75 are attached to the carbonyl groups of the dimer by weaker O-H⋯O hydrogen bonds, forming chains along [101].