The first lanthanide–tetraselenidoantimonate complexes with hexadentate polyamine co-ligand: Solvothermal syntheses of [Sm(peha)(SbSe4)]n and [Eu(peha)(SbSe4)]

•Lanthanide complexes were prepared using hexadentate coligands for the first time.•Tridentate μ-1κ2:2κ-SbSe4 to Sm3 + and bidentate 1κ-SbSe4 to Eu3 + were obtained.•1 and 2 exhibit optical band gaps at 2.04 and 2.11 eV, respectively.

Two lanthanide(III) complexes containing tetraselenidoantimonate ligand [Sm(peha)(μ-1κ2:2κ-SbSe4)]n (1), and [Eu(peha)(1κ2-SbSe4)] (2) (peha = pentaethylenehexamine) were solvothermally prepared by reactions Sb, Se and LnCl3 in pentaethylenehexamine (peha). The tetrahedral [SbSe4]3 − unit connects [Sm(peha)]3 + into the neutral 1-D coordination polymer 1 as a tridentate μ-1κ2:2κ-SbSe4 bridging and chelating ligand. It coordinates to [Eu(peha)]3 + with a 1κ2-SbSe4 chelating mode, forming the mononuclear complex 2. The tridentate μ-1κ2:2κ-SbSe4 bridging and chelating mode and 9-coordinate Sm(III) center in 1 are firstly observed in the systematic syntheses of the Sm/Sb/Se system in different polyethylenediamines. Compounds 1 and 2 exhibit steep band gaps at 2.04 and 2.11 eV at room temperature, respectively.

Graphical abstractThe first lanthanide–tetraselenidoantimonate complexes with hexadentate polyamine co-ligand, [Sm(peha)(SbSe4)]n (1) and [Eu(peha)(SbSe4)] (2) were prepared by solvothermal methods using peha as solvent, and the first μ-1κ2:2κ-SbSe4 ligand to Sm(III) center is observed.Figure optionsDownload full-size imageDownload as PowerPoint slide