Ortho‐Chalcogenotetrelate Anions as Chelating Ligands: Syntheses and Characterization of [K6(MeOH)9][Sn2Se6][Cr(en)2(SnSe4)]2, [Na(H2O)4][Cr(en)3]2[GeS3OH]2[Cr(en)2(GeS4)], and [Ba(H2O)10][{Cr(en)}2(GeSe4)2

Abstract

AbstractReactions of K4[SnSe4], Na4[GeS4] or Ba2[GeSe4] with different 1,2‐diaminoethane (= en) coordinated complexes of CrCl3 ([Cr(en)2Cl2]Cl or [Cr(en)3]Cl3) in MeOH or aqueous solution yielded three novel compounds that contain complexes of Cr3+ with ortho‐chalcogenotetrelate anions [E′E4]4− (E′ = Ge, Sn; E = S; Se): the crystal structures of [K6(MeOH)9][Sn2Se6][Cr(en)2(SnSe4)]2 (1), [Na(H2O)4][Cr(en)3]2[GeS3OH]2[Cr(en)2(GeS4)] (2), and [Ba(H2O)10][{Cr(en)}2(GeSe4)2] (4) have been determined by means of single crystal X‐ray diffraction (1: triclinic space group $P{\bar 1}$; lattice dimensions at 203 K: a = 1175.7(2), b = 1315.3(3), c = 1326.7(3) pm, α = 61.99(3)°, β = 64.05(3)°, γ = 83.57(3)°, V = 1617.4(6)·106 pm3; R1 [I > 2σ(I)] = 0.0788; wR2 = 0.1306; 2: monoclinic space group C2/c; lattice dimensions at 203 K: a = 2445.3(5), b = 1442.5(3), c = 1579.3(3) pm, β = 94.61(3)°, V = 5552.9(19)·106 pm3; R1 [I > 2σ(I)] = 0.0801; wR2 = 0.2046; 4: triclinic space group $P{\bar 1}$; lattice dimension at 203 K: a = 1198.4(2), b = 1236.8(3), c = 1297.5(3) pm, α = 65.69(3)°, β = 63.35(3)°, γ = 81.21(3)°, V = 1565.2(5)·106 pm3; R1 [I > 2σ(I)] = 0.0732; wR2 = 0.1855). 1 and 2 show the yet unprecedented complexation of transition metal ions by non‐bridging, single chalcogenotetrelate ligands to produce dinuclear, heterobimetallic complexes. Compound 2 contains the first structurally characterized complex with an ortho‐thiogermanate ligand. The formation of these compounds, and of a by‐product of 2, [Cr(en)3][GeS3OH]·6H2O (3: monoclinic space group C2/c; lattice dimensions at 203 K: a = 2396.8(5), b = 1463.4(3), c = 1740.1(4) pm, β = 132.99(3)°, V = 4463.8(15)·106 pm3; R1 [I > 2σ(I)] = 0.0462; wR2 = 0.1058), provides some insight in fundamental differences between the reaction behavior of [SnE4]4− anions one the one hand and [GeE4]4− anions on the other hand. The crucial role of the counterion charge becomes evident when comparing the structure motifs of the ternary anions in 1 and 2 with that observed in the Ba2+ compound 4.