N-Benzylisatin

In the title compound, C15H11NO2, two C—H⋯O hydrogen bonds are observed in the crystal structure, as well as π–π stacking with a centroid–centroid distance of 3.623 (2) Å. The planarity of the two ring systems is illustrated by very small deviations of all the atoms from these planes [largest deviations = 0.003 (3) and 0.010 (3) Å for the phenyl and fused-benzene rings, respectively]. The dihedral angle between these two planes is 77.65 (9)°.

In the title compound, C 15 H 11 NO 2 , two C-HÁ Á ÁO hydrogen bonds are observed in the crystal structure, as well asstacking with a centroid-centroid distance of 3.623 (2) Å . The planarity of the two ring systems is illustrated by very small deviations of all the atoms from these planes [largest deviations = 0.003 (3) and 0.010 (3) Å for the phenyl and fused-benzene rings, respectively]. The dihedral angle between these two planes is 77.65 (9) .   Table 1 Hydrogen-bond geometry (Å , ). The molecule isatin has a variety of biological activities. It can cause anxiety but can also be used as a sedative. It can also act as an anticonvulsant agent and can block the binding of an agonist at the atrial natriuretic peptide receptors (Palmer et al., 1987;Goldschmidt & Llewellyn, 1950;Wei et al., 2004;Frolova et al., 1988;Akkurt et al., 2006). Benzylisatin was synthesized to explore the reactivity of the amide group in the isatin molecule and to investigate its possible biological reactivity as free ligand or as bidentate ligand as part of the Re(I) tricarbonyl complex. The coordination of biand tridentate ligand systems to the Re(I) tricarbonyl synthon is part of an ongoing study. The amide group was functionalized in the isatin molecule to illustrate the pH dependent keto-enol tautomerisation of the molecule to coordinate in a bidentate fashion to the Re(I) metal centre. By functionalizing the amide, keto-enol tautomerisation is no The main difference between the structure of N-benzylisatin reported here and that by Akkurt et al. is the packing as a result of the different space groups, P2 1 and P2 1 /c, respectively. In this structure report, the benzylisatin molecules pack in a head-to-toe fashion along the a axis and in layers when viewed along the b axis ( Figure 2). In the structure by Akkurt et al. the molecules pack in a staggered head-to-head fashion when viewed along the c axis.

Related literature
Three C-H···O hydrogen bonds are observed in the structure of N-benzylisatin. One is an intramolecular hydrogen bond and the other two are intermolecular hydrogen bonds to two neighbouring molecules. Some π-stacking is observed in the crystal structure of N-benzylisatin between neighbouring molecules, with a centroid-to-centroid distance of 3.623 (2) Å. This is illustrated in Figure 3.

Experimental
The preparation was performed under strict Schlenk conditions. Isatin (0. reaction mixture was dried, dissolved in ethylacetate and washed three times with water. The combined ethylacetate layers were dried with Na 2 SO 4 . The product was purified with column chromatography with DCM:Hex 1:1 as eluent and monitored with TLC. The resulting orange product was dried under vacuum. Orange crystals were grown from a methanol solution of the product.

Refinement
Aromatic H atoms were positioned geometrically and allowed to ride on their parent atoms, with U iso (H) = 1.2U eq (parent) of the parent atom with a C-H distance of 0.95. The methene H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with U iso (H) = 1.2U eq (C) and at a distance of 0.99 Å.   Packing of the title compound in the unit cell.

Figure 3
Observed π-π stacking in the crystal structure, indicated by dashed lines (hydrogen atoms omitted for clarity). where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.15 e Å −3 Δρ min = −0.19 e Å −3 Special details Experimental. CrysAlis Pro (Oxford Diffraction Ltd, 2007) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. 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 > 2σ(F 2 ) is used only for calculating R-factors(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.