POTASSIUM D-3-PHOSPHOGLYCERATE AND CYCLOHEXYLAMMONIUM D-3-PHOSPHOGLYCERATE HYDRATE

The structures of the D-3-phosphoglycerate monoanions in the potassium [KH2(3-PGA)] and cyclohexylammonium [(CHA)H-2(3-PGA)] salts [H-2(3-PG A) = (HO3POCH2CH)-H--(OH)(CO2H)] have been determined by X-ray analysi s at 297 and 85 K, respectively. The C-C-C-OH torsion angles which def ine the relationship of the carboxylic group to the carbon backbone ar e -120.2(2) and 60.1(3)degrees, and the P-O(ester) bond lengths are 1. 596(2) and 1.600(2) Angstrom for KH2(3-PGA) and (CHA)H-2(3-PGA), respe ctively. There are extensive networks of hydrogen bonds in both crysta ls in which all H atoms of the hydroxyl and ammonium groups are involv ed. The K+ ion is octacoordinate.