Solvothermal syntheses, crystal structures, and properties of new lanthanide compounds based on tetraselenidoantimonate and tetraethylenepentamine mixed ligands

Abstract

New lanthanide(III) compounds [[Ln(tepa)(Cl)]-[Ln(tepa)(OH)] 2 (SbSe 4 ) 2 ] n (Ln=Sm, Eu), [H 2 tepa][[Ln(tepa)-(SbSe 4 )] 2 (OH) 2 ] (Ln=Eu, Gd, Ho) (tepa=tetraethylenepen-tamine) were prepared by solvothermal methods. Acting as a bidentate l-1j:2j-SbSe 4 bridging ligand, the [SbSe 4 ] 3-unit interconnects [[Ln(tepa)] 2 (OH) 2 ] 4? and [Ln(tepa)Cl] 2? (Ln=Sm, Eu) ions to form one-dimensional coordination polymers [[Ln(tepa)(Cl)][Ln(tepa)(OH)] 2 (SbSe 4 ) 2 ] n . The [SbSe 4 ] 3-unit acts as monodentate ligand to Ln(III) centers in [H 2 tepa][[Ln(tepa)(SbSe 4 )] 2 (OH) 2 ]. The different coordination modes of the [SbSe 4 ] 3-units in [[Ln(tepa)(Cl)][Ln-(tepa)(OH)] 2 (SbSe 4 ) 2 ] n and [H 2 tepa][[Ln(tepa)(SbSe 4 )] 2 -(OH) 2 ] are attributed to the size of Ln 3? ions. The bidentate l-1j:2j-SbSe 4 bridging ligand in [[Ln(tepa)(Cl)][Ln(tepa)-(OH)] 2 (SbSe 4 ) 2 ] n is observed in the lanthanide complexes of tetraselenidoantimonate ligands for the first time. All compounds exhibit steep band gaps between 2.04 and 2.31 eV at room temperature. Graphical abstract