The molecular structure of 1,3-dimethyl-2(3H)-imidazolethione (C5H8N2S)

Abstract

The crystal structure of the heterocyclic mole-from N-methylimidazole by conversion into the appropriate cule 1,3-dimethyl-2( 3H)-imidazolethione and its lH n.m.r. dialkylimidazolium iodide and treatment with sulphur in spectrum have been interpreted as showing partial methanolic K,CO,. An X-ray structure determination was double-bond character in the N-C-N system, but no undertaken to decide which of the three structures (a), (b), aromaticity.or (c) (Figure 1) best described the molecule.AN investigation of the molecular structure of 1,3-dimethyl- S S-. s-2(3H)-imidazolethione, (I), was undertaken when it was Me, ) , Me Me, ; &Me N N' s s L=L/ LJ found that the compound had an unusually high melting Crystals suitable for X-ray investigation were grown from point (181-1 82") compared with its 1-methyl-3-ethyl water : orthorhombic, a 8.475 A, b 6.826 A, G 11.306 A, homologue, (11) (51"). Both compounds were synthesized Systematic absences show the

The crystal and molecular structure of 2-mercaptobenzimidazole

“…The bond lengths in the imidazole component are generally longer than those in the free molecule at room temperature (Table 5). Bond angles show good agreement with those of Ansell, Forkey & Moore (1970) with the larger internal angles at the N atoms.…”

Synthesis and Crystal Structures of New 1,3-Disubstituted Imidazoline-2-thiones

“…Earlier, this C=S bond has been considered remarkably long (compared with 1.60Å in a trithiocarbonate as an ill-chosen reference compound), and thus believed to indicate a contribution of the mesoionic imidazolium-2-thiolate (Scheme 2) [7,46]. This point keeps getting reiterated in the literature [38,56].…”

“…This turned out to be a wise decision, because the effect of temperature on the angles in the ring system of this compound obviously is almost as large as the effect of the hetero-atom substituents in the other compounds. Thus, in the reported structures of 10 at room temperature the C-N-C angles within the ring were 108.4 • [7] and 109.2 • [46], whereas at 173 K we found 110.2(2) • . The other thiones reported here which bear N-alkyl substituents exhibit C-N-C ring angles from 110.4(1) • to 110.7(1) • .…”

The structure of 1-(4-imidazolylsulfonyl)-4-phenylimidazole

“…Other examples of base stacking of simple imidazoles are imidazolium dihydrogen orthophosphate (Blessing & McGandy, 1972) and 1,3-dimethyl-2(3H)-imidazolethione (Ansell, Forkey & Moore, 1970) for which stacking views are provided by the authors. Stacking views for imidazole (Martinez-Carrera, 1966) and 1,3-diphosphorylimidazole (Beard & Lenhert, 1968) were drawn and are shown in Fig 5. The overall hydrogen bonding and base stacking appear to be more extensive in 1-(4-imidazolylsulfonyl)-4-phenylimidazole than in other simple imidazoles, but the number of available structures is too small to make any generalizations.…”