Description:
<jats:p><jats:bold>Preparation, Structures, and Thermal Decomposition Reactions of Complexes Consisting of Tl<jats:sup>I</jats:sup>, Pb<jats:sup>II</jats:sup>, and Se<jats:sup>II</jats:sup> and 2,2‐Dicyanoethylene‐1,1‐diselenolate</jats:bold></jats:p><jats:p>The 2,2‐dicyanoethylene‐1,1‐diselenolate‐containing compounds (AsPh<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub>[Tl<jats:sub>2</jats:sub>(Se<jats:sub>2</jats:sub>C=C(CN)<jats:sub>2</jats:sub>)<jats:sub>2</jats:sub>], (AsPh<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub>[Pb(Se<jats:sub>2</jats:sub>C=C‐(CN)<jats:sub>2</jats:sub>)<jats:sub>2</jats:sub>], and (NBu<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub>[Se(Se<jats:sub>2</jats:sub>C=C(CN)<jats:sub>2</jats:sub>)<jats:sub>2</jats:sub>] have been prepared and characterized by single‐crystal structure analysis. The molecular structures of the complex anions <jats:bold>1–3</jats:bold> are significantly influenced by the presence of stereochemically active lone pairs. <jats:bold>1</jats:bold> is dimeric with an Se<jats:sub>4</jats:sub>Tl<jats:sub>2</jats:sub> octahedral centre with a Tl–Tl distance of 3.547(4) Å and an average Tl–Se bond length of 3.143(4) Å. In <jats:bold>2</jats:bold> Pb constitutes the centre of a distorted pseudo‐trigonal bipyramid PbSe<jats:sub>4</jats:sub>E [Pb–Se<jats:sub>ave</jats:sub> = 2.948(3) Å] with one equatorial position obviously occupied by the lonepair E. In <jats:bold>3</jats:bold> the ligands are coordinated to the central Se, which is situated in a centre of symmetry, in an undistorted way giving rise to a Ψ‐octahedral SeSe<jats:sub>4</jats:sub>E<jats:sub>2</jats:sub> geometry [Se–Se<jats:sub>ave</jats:sub> = 2.617(2) Å]. The compounds (AsPh<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub> · <jats:bold>1</jats:bold>, (AsPh<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub> · <jats:bold>2</jats:bold> and (NBu<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub> · <jats:bold>3</jats:bold> have been decomposed thermally to yield TlSe, PbSe as well as Se. The observed contamination of TlSe and PbSe with As is avoided by using (NBu<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub> · <jats:bold>1</jats:bold> and (NBu<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub> · <jats:bold>2</jats:bold> as precursor materials.</jats:p>