Synthesis and Reactivity of Selones and Dihaloselones: Complexation of Selones with d(8)- and d(10)-Metal Ions

摘要

The reactivities of the monodentate selone LSe (L = 1,3-dibutylbenzimidazol-2-ylidene; 10a), the bidentate pyridine-functionalized selone LSe (L = 1-pyridyl-3-butylimidazol-2-ylidene; 10b) and the multidentate ether-functionalized selone LSe {L = 1,3-bis[2-(2-methoxyethoxy)ethyl]benzimidazol-2-ylidene; 10c} with soft transition-metal halides (PdX2, PtX2, ZnX2, CdX2 and HgX2; X = Cl, Br, I) are probed. Compounds 10a and 10c react with metal halides to give complexes of the type [Cu-2(mu-X)(2)(LSe)(2)] (X = Br, I; 11, 12), [MX2(LSe)(2)] (13-22) or [M2X2(mu-X)(2)(LSe)(2)] (X = Cl, Br, I; 26-32), whereas 10b and HgX2 (X = Cl, Br, I) form 1:1 complexes HgX2(LSe) (21-23), in which the pyridine moiety coordinates to the metal centre to form a six-membered chelate. The reactivity of 10a was compared with those of triphenylphosphine and triethylamine. The reaction of 10c with molecular iodine yields the diiodoselone LSeI2 (35), which disproportionates to give the selone adduct of the iodonium ion, [(LSe)(2)I]I-+(3)- (36). The reactions of LSeX2 [X = Cl (34a), Br (34b), I (34c)] with organotellurium compounds, namely, tellone LTe (10d) and diphenyl telluride (37), afford the dihalotellones LTeX2 [X = Cl (38a), Br (38b), I (38c)] and Ph2TeX2 [X = Cl (39a), Br (39b), I (39c)], respectively. The oxidizing properties of LSeX2 (34a-34c) were investigated with rare-earth metals.