REDETERMINATION OF THE STRUCTURE OF GUANINE HYDROCHLORIDE MONOHYDRATE

C5H6N5O+.Cl-.H2O, M(r) = 205.6, monoclinic, P2(1)/c, a = 4.479 (1), b = 9.995 (1), c = 19.304 (2) angstrom, beta = 107.90 (1)-degrees, V = 819.1 (2) angstrom 3, Z = 4, D(m) = 1.664, D(x) = 1.667 g cm-3, lambda(Mo K-alpha) = 0.71073 angstrom, mu = 4.38 cm-1, F(000) = 424, T = 293 (1) K, R = 0.034, wR = 0.043 for 1736 observed reflections with I > 1.96 sigma(I). The guanine molecule is non-planar with a dihedral angle of 1.7 (1.5)-degrees between the imidazole and the pyrimidine rings. The base rings are protonated at N(7) and form a hydrogen network with two modes of pairing [N(7)-H7...O(1) and N(10)-H101...N(3)]. Several interactions of the type D-H...A are noted between purine cations, water and chlorine anions.