(E)-4-(Benzyloxy)benzaldehyde thiosemicarbazone

In the title compound, C15H15N3OS, the thiosemicarbazone group adopts an E configuration with respect to the C=N bond. The benzaldehyde thiosemicarbazone fragment is almost planar [maximum deviation = 0.012 (1) Å], while the dihedral angle between the benzyloxy and phenyl rings is 72.48 (5)°. In the crystal structure, molecules are interconnected by N—H⋯N and N—H⋯S hydrogen bonds, forming a two-dimensional network parallel to the bc plane and are further stacked along the a axis by π–π interactions [centroid–centroid separation 3.9043 (7) Å]. The crystal structure is also stabilized by C—H⋯π interactions.

In the title compound, C 15 H 15 N 3 OS, the thiosemicarbazone group adopts an E configuration with respect to the C N bond. The benzaldehyde thiosemicarbazone fragment is almost planar [maximum deviation = 0.012 (1) Å ], while the dihedral angle between the benzyloxy and phenyl rings is 72.48 (5) . In the crystal structure, molecules are interconnected by N-HÁ Á ÁN and N-HÁ Á ÁS hydrogen bonds, forming a two-dimensional network parallel to the bc plane and are further stacked along the a axis byinteractions [centroid-centroid separation 3.9043 (7) Å ]. The crystal structure is also stabilized by C-HÁ Á Á interactions.

Comment
The chemistry of thiosemicarbazones have been of immense interest because these compounds provide intriguing chelating patterns, profound biomedical properties, structural diversity and ion-sensing abilities (Al-Awadi et al., 2008;Amoedo et al., 2006;Demertzi et al., 2007;Mirsha et al., 2006;Kizilcikli et al., 2004). Compounds of this type have been used as antibacterial, antifungal and antitumor agents (Sing et al., 2001;Offiong et al., 1997). Due to their long chain structure, they are very flexible and form linkages with a variety of metal ions (Chandra et al., 2001). It was advocated that their flexibility and bioactivity arise because of the presence of the imino group (-N=CH-) in addition to thioamino moities present in the skeleton of the molecule. The title thiosemicarbazone derivative (I) was synthesized and its crystal structure is reported here.
(I) is likely to have biomedical properties similar to other nitrogen-sulfur donor ligands studied by our group.

Experimental
The title compound was synthesized by adding a solution of 4-benzyloxybenzaldehyde (2.12 g, 10 mmol) in ethanol (30 ml) to a hot solution of thiosemicarbazide (0.91 g, 10 mmol) in ethanol (100 ml). The mixture was refluxed for 2 hrs and subsequently cooled to room temperature. The light yellow precipitate of the title compound was separated by filtration, washed with ethanol and dried in vacuo over anhydrous CaCl 2 . (Yield: 1.75 g, 61%), and was then dissolved in chloroform (0.11 g in 50 ml) and allowed to stand at room temperature (288-293 K) for 20 days. Yellow single crystals of the title compound were obtained after recrystallization from a solution of chloroform/toluene (30:7 v/v) after 12 days at room temperature, M.p 446 K.
supplementary materials sup-2 Refinement H atoms bound to N atoms were located from a difference Fourier map and refined freely with isotropic displacement parameters. The remaining H atoms were positioned geometrically and allowed to ride on their parent atoms, with d(C-H) = 0.93 Å, for aromatic, 0.97 Å, for CH 2 and U iso = 1.2U eq (C). The highest residual electron density peak is located at 0.69 Å from C8 and the deepest hole is located at 1.19 Å from C12. Fig. 1. The asymmetric unit of the title compound, showing 50% probability displacement ellipsoids and the atomic numbering. The N-H···N intramolecular hydrogen bond is shown as dashed line.

Special details
Experimental. The low-temperature data was collected with the Oxford Cyrosystem Cobra low-temperature attachment. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq S1 −0.13297 (