Structures, spectroscopic studies and solid-state thermal transformations of coordination polymers from P 4Se 3 and CuX (X=Cl, Br, I)

Abstract

The formation of coordination polymers (CuCl)P 4Se 3 ( 1), (CuBr) 3(P 4Se 3) 2 ( 2), (CuI) 3(P 4Se 3) 2 ( 3) and (CuI)P 4Se 3 ( 4), from solutions of copper(I) halides and P 4Se 3 by diffusion methods has been studied. The new compounds were characterized by X-ray crystallography, solid-state 31P MAS NMR and Raman spectroscopy. Theoretical studies on the DFT level in the crystalline phase allowed the unequivocal assignment of the recorded Raman shifts between 200 and 480 cm −1. The structure of 1 consists of a 2D network of castellated [CuCl] n chains and bidentate P 4Se 3 molecules. The 3D network of 2 comprises [CuBr] n chains, which are linked by tridentate P 4Se 3 molecules. Compound 3 is a three-dimensional polymer composed of four-membered (CuI) 2 rings and castellated [CuI] n chains, which are linked by tridentate P 4Se 3 molecules involving two basal and the apical P atoms. Thermal conversion of 1 at 230 °C gives (CuCl) 3(P 4Se 3) 2 ( 5), which is isostructural with 2. The thermal conversion of (CuI) 3P 4S 3, which was studied for comparison gave at 371 °C (CuI) 3P 4S 4, Cu 3PS 4 and small amounts of Cu 6PS 5I.