Crystal structure of fully protonated 3,10,20,21,28-tetraoxo-5,8,23,26-tetrakis(carboxymethyl)-2,5,8,11,20,23,26,29-octaaza[12.12]metacyclophane

A protonated cation salt of title compound C₃₆H₄₈N₈O₁₂ crystallized in the monoclinic space group with cell parameters a = 11.4721(8)Å, b = 23.1049(16)Å, c = 21.0730(14)Å, β = 99.0040(10)° and Z = 4; the final residual factor was 0.0582 with 9694 reflections. A cyclophane conformation was determinated by an interplay between the ridigidy of amide and phenyl groups and the presence of intramolecular hydrogen bonds and C-H···π interactions. 2006