A series of new lanthanoid thioarsenates: insights into the influence of lanthanide contraction on the formation of new lanthanoid thioarsenates

Abstract

A series of new lanthanoid thioarsenates [Ln(teta)(μ–η¹:η²:η¹-As^IIIS₃)]_n {Ln = Ce (Ia), Pr (Ib), Nd (Ic), and Sm (Id); teta = triethylenetetramine} and [Ln(teta)(en)(μ–η¹:η¹:η¹-As^VS₄)]_n {Ln = La (IIa), Ce (IIb), Pr (IIc), and Nd (IId); en = ethylenediamine} were prepared by the solvothermal reaction of K₃AsO₃, S, LnCl₃ and organic amines and structurally characterized. Compounds Ia–d crystallise in the orthorhombic space group Aba2 and display 1-D neutral chains [Ln(teta)(μ–η¹:η²:η¹-As^IIIS₃)]_n, which represent the first examples of 1-D organic hybrid lanthanoid sulfides built up from trigonal-pyramidal [As^IIIS₃]³⁻ acting as tetradentate bridging ligands to interlink [Ln(teta)]³⁺ ions, while compounds IIa–d crystallise in the orthorhombic space group P2₁2₁2₁ and consist of other 1-D neutral chains [Ln(teta)(en)(μ–η¹:η¹:η¹-As^VS₄)]_n, which are built up from the linkages of the tetrahedral [As^VS₄]³⁻ ion and the [Ln(teta)(en)]³⁺ ion. To learn more about the influence of lanthanide contraction on the formation of lanthanoid thioarsenates, three organic hybrid lanthanoid thioarsenates [Ln(teta)(en)As^VS₄] [Ln = Dy (IIIa), Ho (IIIb), and Tm (IIIc)] with the neutral molecular structure type in the monoclinic centrosymmetric space group P2₁/c are also presented. Their optical and magnetic properties have been investigated, and density functional theory calculations of Ia and IIa have also been performed.