[1-(3-Chlorophenyl)-1H-1,2,3-triazol-4-yl]methanol hemihydrate

The asymmetric unit of the title hydrate, C9H8ClN3O·0.5H2O, comprises two independent 1,2,3-triazole molecules and a water molecule of crystallization. The dihedral angles between the six- and five-membered rings in the 1,2,3-triazole molecules are 12.71 (19) and 17.3 (2)°. The most significant different between them is found in the relative orientations of the terminal CH2OH groups with one being close to perpendicular to the five-membered ring [N—C—C—O torsion angle = 82.2 (5)°], while in the other molecule, a notable deviation from a perpendicular disposition is found [torsion angle = −60.3 (5)°]. Supramolecular chains feature in the crystal packing sustained by O—H⋯(O,N) interactions along the a-axis direction. The chains are connected via C—H⋯N interactions and the resultant layers stack along the b axis.

The asymmetric unit of the title hydrate, C 9 H 8 ClN 3 OÁ0.5H 2 O, comprises two independent 1,2,3-triazole molecules and a water molecule of crystallization. The dihedral angles between the six-and five-membered rings in the 1,2,3-triazole molecules are 12.71 (19) and 17.3 (2) . The most significant different between them is found in the relative orientations of the terminal CH 2 OH groups with one being close to perpendicular to the five-membered ring [N-C-C-O torsion angle = 82.2 (5) ], while in the other molecule, a notable deviation from a perpendicular disposition is found [torsion angle = À60.3 (5) ]. Supramolecular chains feature in the crystal packing sustained by O-HÁ Á Á(O,N) interactions along the a-axis direction. The chains are connected via C-HÁ Á ÁN interactions and the resultant layers stack along the b axis.
The use of the EPSRC X-ray crystallographic service at the University of Southampton, England, and the valuable assistance of the staff there is gratefully acknowledged. JLW acknowledges support from CAPES and FAPEMIG (Brazil).

Comment
Boechat and colleagues have been interested in the synthesis, biological activities and structures of 1,2,3-triazole derivatives for some time (Boechat et al., 2010(Boechat et al., , 2011Costa et al., 2006aCosta et al., , 2006bFerreira et al., 2007, Jordão et al., 2009. Recently, they reported the synthesis and anti-mycobacterial activities of a number of 4-R-1-(X-phenyl)-triazole derivatives (Boechat et al., 2011). The structure of one of the compounds investigated in that study, i.e. the title compound, (I), is now reported.
Two independent molecules of a 1,2,3-triazole derivative and a water molecule of solvation comprise the asymmetric unit of (I), Fig. 1. Geometrically, the two organic molecules are similar to each other with r.m.s. deviations for bond distances and angles being 0.0092 Å and 0.757°, respectively (Spek, 2009). From the overlay diagram, Fig. 2, it is evident that the independent molecules approximate mirror images. However, small twists between the five-and six-membered rings differ with the dihedral angles between their least-squares being 12.71 (19) and 17.3 (2)°, respectively, for the N1-and N4-containing molecules. More notable are the relative orientations of the terminal CH 2 OH groups as seen in the values of the N3-C8-C9-O1 and N6-C17-C18-O2 torsion angles of 82.2 (5) and -60.3 (5)°, respectively.
The presence of a supramolecular chain along the a axis is the most prominent feature of the crystal packing, Fig. 3.
These are mediated by O-H···O and O-H···N hydrogen bonds with additional stability afforded by C-H···O interactions, Table 1. Chains are connected into layers via C-H···N interactions, Table 1, and these stack along the b axis. The closest interactions between layers are of the type Cl···Cl, i.e. Cl1···Cl2 i = 3.4117 (15) Å for i: 2 -x, 1 -y, 1 -z.

Experimental
The compound, obtained as published (Boechat et al., 2011), was recrystallized from EtOH as a hemihydrate.

Refinement
The C-bound H atoms were geometrically placed (C-H = 0.95-0.99 Å) and refined as riding with U iso (H) = 1.2U eq (C). The O-H H atoms were located from a difference map and refined with O-H = 0.84±0.01 Å, and with U iso (H) = 1.5U eq (O). Fig. 1. The molecular structures of the components comprising the asymmetric unit in (I) showing displacement ellipsoids at the 50% probability level.