Acta Crystallographica Section C

Crystal Structure Communications

Volume 57, Part 12 (December 2001)

Acta Cryst. (2001). C57, 1443-1446 [doi:10.1107/S0108270101016742]

The 143 and 300 K polymorphs of hexamethylenetetraminium 2,4-dinitrophenolate monohydrate

A. Usman, S. Chantrapromma and H.-K. Fun

Abstract: The title compound, 3,5,7-triaza-1-azoniatricyclo[3.3.1.1^3,7]decane 2,4-dinitrophenolate monohydrate, C₆H₁₃N₄⁺·C₆H₃N₂O₅^-·H₂O, the 1:1 hydrate adduct of hexamethylenetetramine (HMT) and 2,4-dinitrophenol, undergoes a temperature phase transition. In the room-temperature phase, the adduct crystallizes in the monoclinic P2₁/m space group, whereas in the low-temperature phase, the adduct crystallizes in the triclinic P $\overline 1$ space group. This phase transition is reversible, with the transition temperature at 273 K, and the phase transition is governed by hydrogen bonds and weak interactions. In both these temperature-dependent polymorphs, the crystal structure is alternately layered with sheets of hexamethylenetetramine and sheets of dinitrophenol stacked along the c axis. The hexamethylenetetramine and dinitrophenol moieties are linked by intermolecular hydrogen bonds. The water molecule in the adduct plays an important role, forming O-HO hydrogen bonds which, together with C-HO hydrogen bonds, bridge the adducts into molecular ribbons. Extra hydrogen bonds and weak interactions exist for the low-temperature polymorph and these interconnect the molecular ribbons into a three-dimensional packing structure. Also in these two temperature-dependent polymorphs, dinitrophenol acts as a hydrogen-bond acceptor and HMT acts as a hydrogen-bond donor.

Formula: C₆H₁₃N₄⁺·C₆H₃N₂O₅^-·H₂O

Online 6 December 2001


	Structure factor file (CIF format) (93.5 kbytes) Contains datablock Iat300K

	Structure factor file (CIF format) (158.3 kbytes) Contains datablock Iat143K

Notes:

To open or display or play some files, you may need to set your browser up to use the appropriate software. See the full list of file types for an explanation of the different file types and their related mime types and, where available links to sites from where the appropriate software may be obtained.

The download button will force most browsers to prompt for a file name to store the data on your hard disk.

Where possible, images are represented by thumbnails.