Se₂^2-, Se₅^2-, and Se₇^2- Ligands in [NEt₄]₂[As₂Se₆], [enH][AsSe₆]·2.2.2-cryptand, [NEt₄][AsSe₈], and [(en)₂In(SeAs(Se)Se₂)]·en

Abstract

The extraction in ethylenediamine (en) of "AsSe4", "TlAsSe4", and "InAsSe4", followed by reaction with cation sources or 2.2.2-cryptand, has led to the isolation of [NEt4]2[As2Se6] (1), [enH][AsSe6]·2.2.2-cryptand (2), [NEt4][AsSe8] (3), and [(en)2In(SeAs(Se)Se2)]·en (4). These compounds contain AsSe+ units coordinated to Se22-, Se52-, and Se72- ligands in 1 and 4, 2, and 3, respectively. The [As2Se6]2- anion features two AsSe+ units joined by Se22- ligands; the resultant As2Se4 ring exhibits a chair conformation. The [AsSe6]- anion features an AsSe+ unit coordinated in a bidentate fashion by a Se52- ligand to create an AsSe5 ring with a chair conformation. The [AsSe8]- anion contains an AsSe+ unit coordinated by a bidentate Se72- ligand; the resultant AsSe7 ring has a crown conformation. [(en)2In(SeAs(Se)Se2)] features an octahedral In atom bridged by one Se2- and one Se22- ligand to an AsSe+ unit; two bidentate en ligands complete the coordination about the In center.