Studies on Intermolecular Complex Formation. IV. Crystal Structure of Cytosine-Resorcylic acid 2:1 Complex monohydrate

Abstract
The crystal and molecular structure of a cytosine and resorcylic acid complex monohydrate has been solved by the direct method. The molecular complex is formed by two moles of cytosine and one mole of resorcylic acid. The crystals are monoclinic, with a space group of P21/n, and with a=8.335, b=20.605, c=10.159 Å, and β=95.5°. The final R-factor for 1820 reflections is 0.100. Resorcylic acid is hydrogen-bonded to one of the cytosine molecules with one hydrogen bond, and the two cytosine molecules with one hydrogen bond, and the two cytosine molecules are associated with three hydrogen bonds in a system similar to that of the guanine-cytosine hydrogen bond in the Watson-Crick model.