1-Methyl-4-thiocarbamoylpyridin-1-ium iodide

In the title compound, C7H9N2S+·I−, the thioamide moiety is twisted out of the aromatic plane by 38.98 (4)° and forms N—H...I hydrogen bonds. In the crystal, hydrogen-bonded centrosymmetric dimers [C7H9N2S+·I−]2 are linked via additional short contacts from an aromatic CH group to the iodide anion into ribbons parallel to the (010) plane.

In the crystal (Fig. 2), the only significant intermolecular contacts are non-classical hydrogen bonds between H5 and I1 ii , with a separation 0.22 Å shorter than the sum of van der Waals radii (Table 1, entry 3). These link the dimers of ion pairs into ribbons parallel to the (010) plane.

data reports Synthesis and crystallization
The title salt was prepared by a modification of a literature method for related compounds (Kosower, 1955): methyl iodide (0.57 g, 4 mmol) was added dropwise to 4-pyridinethioamide (0.50 g, 4 mmol) in 5.00 ml of dry CH 3 CN, with a colour change from yellow to deep orange. The mixture was stirred for 30 min. at room temperature, followed by reflux for 10 min., cooled, filtered and washed three times with cold CH 3 CN. Recrystallization from boiling 99% ethanol afforded 0.21 g (35% yield) of (I) [CAS registry 749784-54-1]. The crystals are hygroscopic and were stored in a well sealed flask.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2.

Funding information
The Natural Sciences and Engineering Research Council of Canada is gratefully acknowledged for Discovery Grants (RTB). The APEXII diffractometer was purchased with the help of the NSERC and the University of Lethbridge.

Figure 1
The molecular structure of the ion pair with the labelling scheme and 50% displacement ellipsoids.