Molecule of the year 2007

(3,5-Dimethyl-1H-pyrazol-4-ylmethyl)-isopropyl-ammonium chloride monohydrate

Five strong hydrogen bonding interactions of four types (N—H···O, N—H···Cl, O—H···N and O—H···Cl) connect molecules of the title compound in the crystal into corrugated sheets stacked along the a axis. The intermolecular interactions can be discussed in terms of the first through fifth level graph sets and the constructor graph method is particularly useful for vizualization of the supramolecular assembly. This first example of a constructor graph approach to describing a pentary system of hydrogen bonds has been published by Ilia A. Guzei, Lara Spencer, Frankline Keter, and James Darkwa from Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, WI 53706, USA, and Department of Chemistry, University Johannesburg, Auckland Park Kingsway Campus, Johannesburg 2006, South Africa in Acta Cryst. C, 2007, C63, 8, o481-o483.

Molecular Structure Laboratory

Chemistry Department

University of Wisconsin-Madison

The Crystallography Laboratory provides single crystal X-ray crystallographic facilites and services to members of the Chemistry Department and to other collaborators. The laboratory is a part of the Paul Bender Chemical Instrumentation Laboratories that provide access to major shared resources in NMR, MS, ESR, IR, and X-ray diffraction facilities.