Oxychloridoselenites(IV) with cubane-derived anions and stepwise chlorine-to-oxygen exchange.

The novel oxychloridoselenites(IV) [BMIm][Se 3 Cl 13 ] (1), [BMIm][Se 4 Cl 15 O] (2), [BMIm] 2 [Se 4 Cl 14 O 2 ] (3), [BMPyr] 2 [Se 4 Cl 14 O 2 ] (4), [BMPyr] 2 [Se 6 Cl 18 O 4 ] (5), [BMIm] 2 [SeCl 4 O] (6), [BMPyr] 2 [Se 2 Cl 6 O 2 ] (7), and [BMPyr] 2 [Se 6 Cl 14 O 6 ] (8) are prepared by ionic-liquid-based synthesis. Accordingly, SeCl 4 , SeO 2 (1-6), and/or SeOCl 2 (7,8) as the starting materials are reacted in [BMIm]Cl or [BMPyr]Cl as ionic liquid (BMIm: 1-butyl-3-methylimidazolium, BMPyr: 1-butyl-1-methylpyrrolidinium; partially with AlCl 3 in addition). Generally, the composition and structure of title compounds can be derived from the tetrameric, heterocubane-type (SeCl 4 ) 4 as the initial building unit. Thus, chlorine is successively exchanged by oxygen from 1 to 8. Moreover, the four edge-sharing (SeCl 6 ) octahedra in (SeCl 4 ) 4 are increasingly dismantled, ending with a [SeCl 4 O] 2- anion as a single pseudo-octahedron in 6. Based on the weakly coordinating ionic liquid, it is possible to selectively obtain the different species via synthesis near room temperature (20-80 °C). The oxychloridoselenite anions [Se 4 Cl 15 O] - , [Se 4 Cl 14 O 2 ] 2- , [Se 6 Cl 18 O 4 ] 2- , and [Se 6 Cl 14 O 6 ] 2- are obtained for the first time. The title compounds are characterized by X-ray structure analysis based on single crystals and powders as well as by infrared spectroscopy and thermal analysis.