Naloxegol hydrogen oxalate displaying a hydrogen-bonded layer structure

In the salt (5α,6α)-6-[(2,5,8,11,14,17,20-heptaoxadocosan-22-yl)oxy]-3,14-dihydroxy-17-(prop-2-en-1-yl)-4,5-epoxymorphinan-17-ium hydrogen oxalate, C34H54NO11+·C2HO4− the polyether unit of the naloxegol cation adopts the shape of a squashed open letter `O'. In the crystal, the hydrogen oxalate anions are linked into a chain by O—H...O hydrogen bonds. Each naloxegol unit is hydrogen bonded to three hydrogen oxalate ions via two O—H...O and one N—H...O interactions. The resulting hydrogen-bonded two-dimensional layer structure is 3,5-connected and has the 3,5 L50 topology