A NEUTRON-DIFFRACTION STUDY OF HYDROGEN-BONDING IN THE DEUTERIUM (HYDROGEN) L-ARGININE PHOSPHATE MONOHYDRATE

The crystal structure of the title compound D (H)LAP with chemical for mula (D2N)(2)CND .(CH2)(3)CH(ND3)CO2 . D2PO4. D2O has been determined by single crystal neutron diffraction. Positional and thermal paramete rs of atoms were refined by block diagonal matrix least-squares techni que. A final R(f) value of 0.048 was obtained for 1040 observed indepe ndent reflections. The crystal structure consists of alternate layers of phosphate groups and ariginine molecules stacked along the a-axis a nd held together by hydrogen bonds. By deuteration of HLAP, the deuter iums occupy hydrogen positions except those hydrogen atoms bonded to c arbon atoms. All the D(H) bond lengths in D(H)LAP are about 10% to 30% longer than those in HLAP. And bond angles are obviously different fr om references [1] and [2].