CRYSTAL AND MOLECULAR-STRUCTURE OF PENTA(CYCLOHEXYLAMMONIUM) D-2,3-DIPHOSPHOGLYCERATE TRIHEMIHYDRATE

The crystals of penta(cyclohexylammonium) D-2,3-diphosphoglycerate tri hemihydrate an orthorhombic, space group P2(1)2(1)2(1), a = 6.404(3), b = 22.75(1), c = 30.78(1) angstrom. The structure has been determined by X-ray diffraction methods, and refined by full-matrix least-square s technique to R = 0.065 for 2802 non-zero (hkl) and (hklBAR) reflecti ons. The D-2,3-diphosphoglycerate anion adopted extended conformation with the phosphate groups at the extreme end. The carboxylate group ma kes a dihedral angle of 70.2(8)-degrees with the plane through the gly cerate carbon backbone. The lengths of the P - O ester bond are 1.635( 7) and 1.624(7) angstrom at the position-2 and 3, respectively. The cr ystal structure is stabilized by two-dimensional hydrogen-bond nets pe rpendicular to c axis.