Temperature Influence on the Formation of Selenidoantimonates: Solvothermal Syntheses, Crystal Structures and Thermal Properties of [Ni(dien)₂]₂Sb₂Se₆, [Mn(dien)₂]₂(SbSe₄)(Cl), [Co(dien)₂]₂(SbSe₄)(Br), and [Co(dien)₂]₃(SbSe₄)₂

Abstract

Abstract New selenidoantimonats [Ni(dien) 2 ] 2 Sb 2 Se 6 ( 1 ), [Mn(dien) 2 ] 2 (SbSe 4 )(Cl) ( 2 ), [Co(dien) 2 ] 2 (SbSe 4 )(Br) ( 3 ), and [Co(dien) 2 ] 3 (SbSe 4 ) 2 ( 4 ) (dien = diethylenetriamine) were solvothermally synthesized in dien solvent at 180 °C. The crystal structure of 1 consists of two octahedral [Ni(dien) 2 ] 2+ cations and a mixed‐valent [Sb 2 Se 6 ] 4− anion. The isolated [Sb 2 Se 6 ] 4− anion is formed by a Sb III Se 3 trigonal pyramid and a Sb V Se 4 tetrahedron sharing a common corner. 2 and 3 are composed of octahedral [M(dien) 2 ] 2+ cations, tetrahedral [SbSe 4 ] 3− anions and halide ions forming an extended network through hydrogen‐bonding interactions. In 4 the [Co(1)(dien) 2 ] 2+ , [Co(2)(dien) 2 ] 2+ and [SbSe 4 ] 3− ions form layered structures via N–H···Se hydrogen bonds. The [Co(3)(dien) 2 ] 2+ ion is located between the layers, and interacts with the layers by N–H···Se bonds. The synthesis and solid state structural studies on the title compounds show that the higher reaction temperature is helpful for the formation of selenidoantimonate(V) compounds in the synthesis of selenidoantimonate from the M 2+ /Sb/Se/dien system. 1 – 4 start to decompose at temperature about 210 °C in N 2 atmosphere. They lose dien ligands at a wide temperature range of 210–450 °C with multisteps for 1 – 3 and a single step for 4 .