Synthesis, characterization, and X‐Ray crystallographic structure of 1,3‐dimethyl‐2(3H)‐imidazoleselone

NHCs in Main Group Chemistry

“…918,919 Analogously, reactions of NHC−AgCl complexes with elemental sulfur led to the formation of thiones. 920 Oxidation of [SIMes-H]I with PhI(OAc) 2 in the presence of succinimide 921 Free or in situ generated NHCs react with elemental sulfur, 926−932 selenium, [54][55][56][927][928][929]933,934 and tellurium [927][928][929]935,936 similarly to other main group compounds with unshared electron pairs (e.g., phosphines or heavier carbene analogues) to give the corresponding chalcogenoureas 1054−1056 in high yields (Scheme 240). Reactivity of other NHCs (e.g., CAACs, 927 1,2,4-triazolin-5-ylidenes, 937,938 and bis(imidazolidin-2-ylidenes) 939,940 ) toward elemental chalcogens is similar.…”

“…981 First representatives of this class of compounds, the dihalo(imidazolium)sulfuranes 1091 (Scheme 249, X = Cl, Br; R, R′ = Me, H), have been obtained in the late 1970s by reaction of N,N-dimethylimidazolin-2-thione and molecular chlorine or bromine. 982 Selenoureas react with bromine 933,964,983,984 and chlorine 984 similarly, yielding adducts 1092 (Ch = Se, X = Br, Cl). Both thiones and selenones form respective dicationic dichalcogenides 1074 and 1075 (cf., section 2.6.2, Scheme 245), if 0.5 981,989 Moreover, the HOMO energy level of the latter is lower than the LUMO energy level of I 2 , which makes the formation of charge-transfer adducts energetically favorable in this case.…”

N-Heterocyclic Carbene Adducts of Main Group Elements and Their Use as Ligands in Transition Metal Chemistry

“…(IMe)Se was later isolated and structurally characterized by another group. 642 The DuPont chemists were interested in (IMe)S and other imidazolin-2-thiones as novel cross-linkers for the preparation of water-soluble car paint. Because the published route was not suitable for a production on an industrial scale, another protocol was developed that started from imidazolium salts with sodium methoxide as base.…”

“…Similar to the thione ligands described above, the coordination chemistry of N-heterocyclic selones has been studied long before the discovery of their synthetic accessibility from the reaction of free carbenes with elemental selenium, which was first documented for the preparation (IMe)Se from 1,3dimethylimidazolium iodide, K 2 CO 3 , and gray Se. 641,642 A series of selenoureas was already reported by Warner in 1963 from the reaction of carbon diselenide (CSe 2 ) with primary amines, which also afforded the cyclic selenoureas benzimidazolin-2-selone and imidazolidin-2-selone by use of o-phenylenediamine or ethylenediamine, respectively. 841 The latter was also prepared from the corresponding thione by methylation and displacement of the thiomethyl moiety by the hydroselenide ion.…”

Bioinorganic Chemistry in Thyroid Gland: Effect of Antithyroid Drugs on Peroxidase‐Catalyzed Oxidation and Iodination Reactions

“…The -methylated derivative of 2 (1,3-dimethylimidazole-2-selone), on the other hand, produces a hypervalent “T-shaped” compound having I−Se−I moiety [62, 63]. It should be noted that the reaction of the methylated analogue of 2, 1,3-dimethylimidazole-2-selone, with one equivalent bromine affords a hypervalent compound having Br−Se−Br moiety, whereas the corresponding reaction utilizing a half-equivalent bromine leads to the formation of a diselenide dication having two as counterions [64]. Therefore, the existence of 2 in its zwitterionic (or selenolate) form is probably responsible for its different reactivity toward iodine.…”