Hydrothermal synthesis of [C 6H 16N 2][In 2Se 3(Se 2)]: A new one-dimensional indium selenide

Abstract

A new organically templated indium selenide, [C 6H 16N 2][In 2Se 3(Se 2)], has been prepared hydrothermally from the reaction of indium, selenium and trans-1,4-diaminocyclohexane in water at 170 °C. This material was characterised by single-crystal and powder X-ray diffraction, thermogravimetric analysis, UV–vis diffuse reflectance spectroscopy, FT-IR and elemental analysis. The compound crystallises in the monoclinic space group C2/ c ( a=12.0221(16) Å, b=11.2498(15) Å, c=12.8470(17) Å, β=110.514(6)°). The crystal structure of [C 6H 16N 2][In 2Se 3(Se 2)] contains anionic chains of stoichiometry [In 2Se 3(Se 2)] 2−, which are aligned parallel to the [1 0 1] direction, and separated by diprotonated trans-1,4-diaminocyclohexane cations. The [In 2Se 3(Se 2)] 2− chains, which consist of alternating four-membered [In 2Se 2] and five-membered [In 2Se 3] rings, contain perselenide (Se 2) 2− units. UV–vis diffuse reflectance spectroscopy indicates that [C 6H 16N 2][In 2Se 3(Se 2)] has a band gap of 2.23(1) eV.