1,2,3-Dithiazolyl and 1,2,35-Dithiadiazolyl Radicals as Spin-Bearing ...

observed in the precursor III-1 was found to be 1.241(4) Å which is unchanged within
one e.s.d. which is also consistent with the highly similar infrared absorption
frequencies. The nominally single bond C1-O1 distance in III-3 is 1.391(6) Å, while the
analogous bond distance in III-1is 1.347(5) Å. While not substantial, the difference
cannot be ignored. This difference is most likely due to the σ-donating properties of the
methyl group.
Compound III-3 has short intermolecular contacts between neighbouring
molecules in the solid state as shown in Figure 3-4. The oxygen of the carbonyl attached
to the ring is oriented directly toward the two sulfur atoms of a neighbouring molecule.
The O...S distances are 2.757(9) and 2.966(7) Å which are well within the sum of the van
der Waals radii of sulfur and oxygen. The diagram in Figure 3-3 is shown normal to the a
axis and the chain propagates along the [010] direction.
Figure 3-4. Chains of III-3 propagating along the [010] direction by short S-O contacts.
There is only one molecule in the asymmetric unit and therefore the other three
molecules in the unit cell are related by the symmetry operations of the P2 1 /n space
group. A depiction of the unit cell can be seen in Figure 3-5. As is evident from the
diagram, the unit cell possesses a center of symmetry. The molecules are also related via
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