(3RS)-S-[1-(3-Chlorophenyl)-2-oxopyrrolidin-3-yl]-N,N′-dimethylthiouronium bromide

The title molecule, C13H17ClN3OS+·Br−, consists of benzene and pyrrolidine rings and an S–C(NHCH3)2 group. The central C—N bond lengths in the S–C(NHCH3)2 fragment indicate partial double-bond character. Molecules are interconnected into chains by N—H⋯Br hydrogen bonds and the chains are linked into pairs by weak C—H⋯Br hydrogen bonds.


Related literature
For the reactivity of the title compound, see: Hanusek et al. (2004);Sedlá k et al. (2002Sedlá k et al. ( , 2003. For a related structure, see: Hanusek et al. (2009). Experimental Crystal data

Comment
In our previous papers we have discussed the reactivity of the title structure (Sedlák et al., 2002(Sedlák et al., , 2003Hanusek et al., 2004).
In continuation of the above mentioned studies, the related crystal structures of the title compound (Scheme 1, Figs. 1 and 2) as well as of the non-methylated analogue (Hanusek et al., 2009) have been determined and the influence of the N-methyl substituents on the crystal structure has been examined.
All the isothiouronium cations that have been studied in the solid state take part in the hydrogen bonding with different anions. (These anions comprise Clas well as complex organic anions.) Also in the title compound and its non-methylated analogue such interactions are present. In the title structure, there is a motif N2-H2···Br1···H1-N1 that links the molecules into the infinite chains parallel to the b axis (Fig. 2, Tab. 1). Moreover, the pairs of these chains are interconnected by additional C-H···Br contacts to give columns parallel to the b axis. These pairs of the chains are linked by the virtue of two-fold screw axes. There is also a weak C-H···π-electron interaction with π-electrons of the chlorophenyl ring (Tab. 1).

Experimental
The title compound was synthesized according to Hanusek et al. (2004) from saturated acetone solutions of the racemic 3-bromo-1-(3-chlorophenyl)pyrrolidin-2-one and N,N'-dimethylthiourea. Single crystals (blocks) suitable for analysis were grown directly from the reaction mixture. Their average size was 0.3×0.3×0.2 mm

Refinement
All the hydrogens were discernible in the difference electron density map, nevertheless they were situated into the idealized positions. Except for for the H(N) that are involved in the hydrogen bonding and therefore their coordinates were refined without constraints or restraints the rest of the hydrogens were refined riding on their parent C: C-H = 0.95, O.98, 0.99, 1.00 Å for the aryl, methyl, methylene and methine hydrogens, respectively. U iso (H)=1.2U eq (C/N) for the H(N), methylene and methine H atoms, while U iso (H)=1.5U eq for methyl hydrogens.  and ω scans h = −19→16 Absorption correction: gaussian integration (Coppens, 1970) k = −8→9

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.

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