1,3-Dicyclohexyl-3-[(pyridin-2-yl)carbonyl]urea monohydrate from synchrotron radiation

The title urea derivative crystallizes as a monohydrate, C19H27N3O2·H2O. The central C3N grouping is almost planar (r.m.s. deviation = 0.0092 Å), and the amide and pyridine groups are substantially twisted out this plane [dihedral angles = 62.80 (12) and 34.98 (10)°, respectively]. Supramolecular double chains propagating along the b-axis direction feature in the crystal packing whereby linear chains sustained by N—H⋯O hydrogen bonds formed between the amide groups are linked by helical chains of water molecules (linked by O—H⋯O hydrogen bonds). The H atom that participates in these water chains is disordered over two positions of equal occupancy. The double chains are connected into a two-dimensional array by C—H⋯O contacts and the layers stack along the a axis.

The title urea derivative crystallizes as a monohydrate, C 19 H 27 N 3 O 2 ÁH 2 O. The central C 3 N grouping is almost planar (r.m.s. deviation = 0.0092 Å ), and the amide and pyridine groups are substantially twisted out this plane [dihedral angles = 62.80 (12) and 34.98 (10) , respectively]. Supramolecular double chains propagating along the b-axis direction feature in the crystal packing whereby linear chains sustained by N-HÁ Á ÁO hydrogen bonds formed between the amide groups are linked by helical chains of water molecules (linked by O-HÁ Á ÁO hydrogen bonds). The H atom that participates in these water chains is disordered over two positions of equal occupancy. The double chains are connected into a twodimensional array by C-HÁ Á ÁO contacts and the layers stack along the a axis.
We thank Professor W. Clegg and the synchrotron component, based at Daresbury, of the EPSRC National Crystallographic Service, University of Southampton, for the data collection. JLW acknowledges support from CAPES and FAPEMIG (Brazil).

2-carbonyl)urea, (I).
A molecule of N, N'-dicyclohexyl-N-(pyridine-2-carbonyl)urea and a water molecule of solvation comprise the asymmetric unit of (I). Two of the water bound H atoms are disordered and have been assigned site occupancy factors of 0.50.
The disorder is accounted for in terms of the dictates of hydrogen bonding in the crystal structure, see below. The pyridine ring is twisted out of the central C 3 N plane (r.m.s. deviation = 0.0092 Å) with the dihedral angle being 34.98 (10) °. The amide group is even more twisted out of the plane through the central ring forming a dihedral angle of 62.80 (12) °. Each of the cyclohexyl rings adopts a chair conformation.
Hydrogen bonding of the type O-H···O and N-H···O lead to the formation of supramolecular chains along the b axis, Table 1. The amide groups self-associate to form linear chains. Pairs of chains are linked by hydrogen bonding interactions involving the water molecules. Thus, the carbonyl-O2 atom is linked to the water molecule, and the remaining water-H atoms (each with site occupancy factor = 1/2) link water molecules into a helical chain, Fig. 2. The chains are linked into layers via C-H···O interactions, Table 1, which stack along the a direction.