A series of lanthanoid selenidoantimonates(v): rare examples of lanthanoid selenidoantimonates based on dinuclear lanthanide complexes

Abstract

A series of new lanthanoid selenidoantimonates(V) [Ln(en)(tepa)SbSe₄] (Ln = La (Ia), Ce (Ib), Pr (Ic); en = ethylenediamine, tepa = tetraethylenepentamine) and [Ln₂(tepa)₂(μ-OH)₂Cl₂]-{[Ln(tepa)]₂(μ-OH)₂(SbSe₄)₂} (Ln = Y (IIa), Sm (IIb), Gd (IIc), Tb (IId), Dy (IIe), and Tm (IIf)) were solvothermally synthesized and structurally characterized. The structures of Ia–c consist of neutral molecules [Ln(en)(tepa)SbSe₄], where the tetrahedral [SbSe₄]³⁻ anion acts as a ligand to chelate the [Ln(en)(tepa)]³⁺ cation. The structures of IIa–f contain isolated dinuclear [Ln₂(tepa)₂(μ-OH)₂Cl₂]²⁺ cations built up from two [Ln(tepa)Cl]²⁺ ions linked by two –OH bridging groups and organic decorated {[Ln(tepa)]₂(μ-OH)₂(SbSe₄)₂}²⁻ anions based on two [Ln(tepa)SbSe₄] units bridged by two –OH groups. Although a few lanthanoid selenidoantimonates(V) under solvothermal conditions have been reported, their lanthanide complexes normally appear mononuclear. Hence, IIa–f are rare examples of lanthanoid selenidoantimonates based on dinuclear lanthanide complexes. A preliminary investigation of nine lanthanoid selenidoantimonates(V) shows that the well-known lanthanide contraction has a significant influence on the formation of lanthanoid selenidoantimonates(V) under solvothermal conditions. The absorption edges of all compounds have been investigated by UV-vis spectroscopy, and density functional theory calculations for Ia and IIc have also been performed.