Dibenzo[b,f][1,4]thiazepin-11-yl-diethyl-amine

In the title compound, C17H18N2S, the thiazepine ring adopts a boat conformation and the dihedral angle between the benzene rings is 75.92 (5)°, resulting in a butterfly-like conformation. In the crystal, molecules are connected via weak Caromatic—H⋯N contacts involving the imine N atom as acceptor and through a quite short C—H⋯π interaction. The resulting molecular chains propagate along the c-axis direction.

In the title compound, C 17 H 18 N 2 S, the thiazepine ring adopts a boat conformation and the dihedral angle between the benzene rings is 75.92 (5) , resulting in a butterfly-like conformation. In the crystal, molecules are connected via weak C aromatic -HÁ Á ÁN contacts involving the imine N atom as acceptor and through a quite short C-HÁ Á Á interaction. The resulting molecular chains propagate along the c-axis direction.
Cg is the centroid of the C8-C12 ring. Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: SIR92 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: PARST (Nardelli, 1995). Many antidepressant drugs have a tricyclic structure with two aromatic rings fused to a central seven membered ring, on which one or more heteroatoms can be present. In this context, dibenzothiazepines are a class of heterocyclic scaffolds containing nitrogen and sulfur which belong to the class of the so-called "privileged structures", i.e. structures "able to provide high affinity ligands for more than one type of receptor" (Evans et al. 1988;Patchett & Nargund 2000;Fedi et al. 2008). In fact the dibenzothiazepine skeleton has a broad spectrum of medical applications; its derivatives are used to treat schizophrenia and also find applications as neuroleptics, antidepressants, antihistaminic, just to name a few (Ganesh et al. 2011;Pettersson et al. 2009;Riedel et al. 2007;Warawa et al. 2001). Within our programme research concerning the structural elucidation of tricyclic molecules in order to gain further insights into structure-property relationships (Altamura et al., 2008;Altamura et al., 2009;Altamura et al., 2011) we investigated the crystal and molecular structure of the title compound. The overall shape of the tricyclic skeleton is controlled both by the conformation of the central seven-membered ring and the relative arrangement of the aromatic rings bound to it. The central thiazepine ring adopts the usual boat conformation, with C1, C2, C8 and C9 as the basal plane, the S atom as the bow and the N1-C7 bond as the stern. The deviation from a pure boat conformation is quite small as can be seen from the asymmetry index ΔC s which is 3.97°; the bow angle is 51.04 (8)° and the stern angle is 41.89 (8)° (Duax et al. 1976;Bertolasi et al. 1982;Ravikumar & Sridhar, 2005). Finally, the dihedral angle between the benzene rings is 104.08 (5)°. As a consequence the dibenzothiazepine tricyclic skeleton assumes an overall butterfly-like shape (Fig. 1). The N2-C7 bond is shorter than an usual N-C single bond [1.368 (2) Å compared to 1.416 Å (Allen et al. 1987)] and the sum of the bond angles about N2 is 358°; consequently, N2 has a partial sp 2 character. Molecular chains, which propagate along the c axis, are formed through intermolecular interactions (Fig. 2): a weak C-H aromatic ···N contact which involves the imine nitrogen atom as acceptor and a quite short C-H···π interaction (Table 1).

Experimental
The synthesis of the title compound started from the commercially available tricyclic lactam (

Refinement
All the H atoms were positioned with idealized geometry using a riding model and refined with U iso (H) 1.2 times U eq (C) (1.5 for methyl H atoms).

Figure 1
Crystal structure of the title compound with labelling and displacement ellipsoids drawn at the 50% probability level.

Figure 2
Crystal structure of the title compound with view along the b-axis. Intermolecular H-bonding interactions are shown as dashed lines.  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.23 e Å −3 Δρ min = −0.26 e Å −3 Special details 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.