Further structural motifs from the reactions of thioamides with diiodine and the interhalogens iodine monobromide and iodine monochloride: an FT-Raman and crystallographic study

The reactions of the thioamides thiourea, tu, 1-ethyl-2-thiourea, etu, 1,3- dimethyl-2-thiourea, dmtu, 1,3-diethyl-2-thiourea, detu, 3-methylbenzothiaz ole-2-thione, mbtt and 3-methylrhodanine, mrh, with one equivalent of diiod ine have been studied; attempts have been made to characterise the resultan t 1:1 addition products using FT-Raman spectroscopy. It has been shown that these materials lie on a CT-ionic borderline. The crystal structure of dmt u . I-2 has been determined and is shown to be ionic and of the form [(dmtu )(2)I]I-+(3)-, an arrangement previously only rarely found in crystallograp hic reports. The reactions of etu and dmtu with iodine monobromide and iodi ne monochloride and of mbtt with iodine monobromide give 1:1 interhalogen a ddition products; initial FT-Raman investigations point to these adopting a CT 'spoke' structure. The reaction of tu with two equivalents of diiodine to give a bulk material of stoichiometry tu . I-4 has been studied in detai l and shown to lead to a variety of novel polyiodide arrangements, the crys tal structures of two of which are reported, (tu)(2)(I-2)(3) and (tu)(3)(I- 2)(5), and compared to each other, the previously reported (tu)(2)I-2 and t o tu itself. These two structures represent further, previously unreported, structural motifs available for these highly complicated systems.