Crystal and molecular structure of putrescinium hydrogen phosphate dihydrate

Abstract

The X-ray structure of putrescinium hydrogen phosphate dihydrate,$H_3 \mathop N\limits^ + (CH_2 )_4 \mathop N\limits^ + H_3 \cdot HPO_4^{2 - } \cdot 2H_2 O$, has been determined from three-dimensional diffractometer data and refined by full-matrix least-squares techniques. The crystals are monoclinic,P2₁/c, a=6.5932(4),b=16.776(1),c=9.2375(7) Å,β=95.772(6)°, andZ=4; finalR=0.036 for 1360 observed reflections. The putrescinium dication has the all-trans conformation. The structure contains a three-dimensional network of H bonds in which all available proton do nors are utilized. Each of the$- \mathop N\limits^ + H_3$ groups interacts with three electron-rich atoms arranged in an equilateral triangle, but the character of the individual N-H⋯O bonds is different at opposite sides of the dication. The water molecules are involved in relatively strong H bonds but they do not interact with the cation.