Heteroleptic compounds of bismuth(III) adopting a new binuclear structural type: hexamethylenedithiocarbamato(HmDtc)-chloride of [Bi2(S2CNHm)4(μ2-Cl)2] (I) and its solvated form [Bi2(S2CNHm)4(μ2-Cl)2]·2CH2Cl2 (II) have been isolated and studied by X-ray diffraction, IR spectroscopy, and simultaneous thermal analysis. Despite the identical chemical composition, the structure of binuclear molecules in I and II differs significantly. In the first case, the noncentrosymmetric molecule includes two nonequivalent moieties of [Bi(S2CNHm)2Cl], which are combined by μ2-Cl ligands to form the [Bi–(μ2-Cl)2–Bi] metallocycle in the butterfly conformation: Bi(1)–Bi(2) 4.0785(5) Å, Cl(1)–Cl(2) 3.936(2) Å. On the contrary, in the solvated form II, the complex is centrosymmetric and four-membered [Bi2Cl2] ring is stabilized in a rhombic configuration: Bi(1)–Bi(1)a 3.9592(9) Å and Cl(1)–Cl(1)a 4.540(4) Å. According to the microprobe method, the main residual substance after the thermolysis of the complexes is microcrystalline Bi2S3 with inclusions of metallic bismuth particles.
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