The first examples of thiogermanate anion [GeS₃(SH)]³⁻as a bridging ligand to a lanthanide complex

Abstract

Two new lanthanoid thiogermanates [Ln(dien)(2)(μ-η(1),η(2)-GeS(3)(SH))](n) {Ln = La(), Nd(); dien = diethylenetriamine} were solvothermally synthesized and structurally characterized. Both and represent the first examples of the soft Lewis basic [GeS(3)(SH)](3-) anions as tridentate bridging ligand to hard Lewis acidic Ln(3+) ions. Both and exhibit semiconducting properties with absorption band edges of 2.11 eV for and 2.28 eV for . The DFT study of indicates a direct band gap with an electronic transfer excitation of S 3p to both Ge 4s and La 5d orbital electrons.

Solvothermal syntheses of lanthanide thiogermanates displaying three new structural moieties

“…The -SH group has also been reported in the other suldes [Ni(tepa)] 2 [In 4 S 7 (SH) 2 ]$H 2 O 22 and [Ln(dien) 2 (m-h 1 ,h 2 -GeS 3 (SH))] n (Ln ¼ La, Nd). 7 There are a lot of weak N-H/S hydrogen bonds between -NH groups and S atoms of [GeS 3 (SH)] 3À anions. The [Ho(trien)(en)-GeS 4 H] molecules are connected via N-H/S hydrogen bonds to form lays parallel to the (100) plane (Fig.…”

“…The [GeS 4 ] tetrahedra under solvothermal conditions exhibit a characteristic tendency to condense via corner-or edgebridging forming dimeric [Ge 2 S 6 ] 4À or [Ge 4 S 10 ] 4À moieties with transition metal complexes as counterions. 5 But simply noncondensed [GeS 4 ] 4À or [GeS 3 (SH)] 3À anion combined with lanthanide complexes is very scarce, and appear to be limited to that of [Ln(dien) 2 (GeS 3 (SH))] n (Ln ¼ La, Nd), 7 where the [GeS 3 (SH)] 3À anion acts as a [m-h 1 ,h 2 -GeS 3 (SH)] bridging ligand to [Ln(dien) 2 ] 3+ group to form a 1-D coordination polymer. The [GeS 3 (SH)] 3À anion in III acting as bidentate chelating ligand is the second example of noncondensed [GeS 4 ] 4À or [GeS 3 (SH)] 3À species with lanthanide complexes under solvothermal conditions.…”

“…Evidently, two types of lanthanide complex cations are related to the Ln 3+ ion size. To complete a coordination number of nine for both La 3+ and Nd 3+ ions, and eight for Ho 3+ ion, the [GeS 3 (SH)] 3À anion coordinates to unsaturated [Ln(dien) 2 ] 3+ or [Ho(trien)(en)] 3+ ions forming 1-D neutral chains [Ln(dien) 2 (GeS 3 (SH))] n (Ln ¼ La, Nd) 7 and molecular [Ho(trien)(en)GeS 3 (SH)] (III). These results demonstrated that lanthanide contraction has a signicant inuence on the formation of lanthanide thiogermanates under solvothermal conditions.…”

“…4 When transition metal complexes substitute for nonchelating amines or tetraalkyl-ammonium ions, thiogermanate anions are strongly dominated by [Ge 2 S 6 ] 4À or [Ge 4 S 10 ] 4À moieties. 5 Notably, the noncondensed [GeS 4 ] 4À mode in organic hybrid thiogermanates is very scarce, and appear to be limited to that of [VO(dien)] 2 GeS 4 , 6 [Ln(dien) 2 (GeS 3 (SH))] n (Ln ¼ La, Nd), 7 and [Na(H 2 O) 3 ]-[Cr(en) 3 ] 2 [GeS 3 (OH)] 2 [Cr(en) 2 (GeS 4 )], 8 where the [GeS 4 ] 4À ion is stabilized by coordinating to metal complex. More interestingly, the cations of these thiogermanates are either protonated amine or transition metal complex cations, 3,5,6,8 but the thiogermanates with lanthanide-containing counter cation prepared under mild solvothermal conditions have been still a less explored area.…”

“…12 However, the synthesis of lanthanide chalcogenides modied with organic components are hampered by the heat, water, oxygen and light sensitivity of these materials, and the difficulty of so Lewis basic Q 2À ligands (Q ¼ S, Se, Te) coordinating to the hard Lewis acidic Ln 3+ ions via Ln-Q bonds in the solvents. 13 Recently, we have attempted the preparation of lanthanide thiogermanates in chelating amine solutions by the solvothermal methods allowing access to thermodynamically metastable phases, and prepared four organic hybrid lanthanide thiogermanates, [Eu(dien 14 and [Ln(dien) 2 (GeS 3 (SH))] n (Ln ¼ La, Nd), 7 where the so Lewis basic [Ge 2 S 6 ] 4À and [GeS 3 (SH)] 3À units act as ligands to the hard Lewis acidic Ln 3+ ions. To investigate systematically inuence of the well-known lanthanide contraction and different chelating organic amines on the formation of lanthanide thiogermanates, we started to explore the system LnCl 3 /GeO 2 /S/amine under solvothermal conditions, and successfully synthesized a series of organic hybrid lanthanide thiogermanates, [Ln(dien) 3 ] 2 [Ge 2 S 6 ]Cl 2 [Ln ¼ Pr (Ia), Sm (Ib), Gd (Ic), Dy (Id)], [Er 2 (dien) 4 (m-OH) 2 ][Ge 2 S 6 ] (II) and [Ho(trien)(en)GeS 3 (SH)] (III).…”