Nura Suleiman Gwaram - Two new polymorphs of 2,6-diaminopyrimidin-4(3H)-one monohydrate, Acta Cryst. (2011). C67, o6–o9

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      Publication Details (including relevant citation   information):

      Nura Suleiman Gwaram, Hamid Khaledi, Hapipah Mohd Ali and Marilyn   M. Olmstead

      Acta Cryst. (2011). C67, o6–o9

      aDepartment of Chemistry, University of Malaya, 50603 Kuala   Lumpur, Malaysia,
      and bDepartment of Chemistry, University of California, One   Shields Avenue, Davis,
      CA 95616, USA
      Correspondence e-mail:
      Received 9 October 2010
      Accepted 9 November 2010
      Online 8 December 2010


      The title compound, C4H6N4OH2O, crystallized simultaneously
      as a triclinic and a monoclinic polymorph from an
      aqueous solution of 2,4-diaminopyrimidin-6-ol. Previously, an
      orthorhombic polymorph was isolated under the same
      experimental conditions. The molecular geometric parameters
      in the two present polymorphs and the previously reported
      orthorhombic polymorph are similar, but the structures differ
      in the details of their crystal packing. In the triclinic   system,
      the diaminopyrimidinone molecules are connected to one
      another via N—H O and N—H N hydrogen bonding to
      form infinite chains in the [011] direction. The chains are
      further hydrogen bonded to the water molecules, resulting in   a
      three-dimensional network. In the monoclinic system, the
      diaminopyrimidinone molecules are hydrogen bonded
      together into two-dimensional networks parallel to the bc
      plane. The water molecules link the planes to form a   threedimensional
      polymeric structure.

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