Synthesis and structure-dependent optical properties of two new organic–inorganic hybrid antimony(iii) chlorides

Abstract

Two organic–inorganic hybrid antimony(III) chlorides, namely (C₉H₂₆N₃)₂Sb₄Cl₁₈ (1) and (C₉H₂₆N₃)SbCl₆ (2), were prepared using a facile solvent evaporation method. They have low-dimensional structures constructed from SbCl₆ octahedra and triply protonated N,N,N′,N′′,N′′-pentamethyldiethylenetriamine cations. The organic cations exhibit different conformations in the two compounds. Compound 1 crystallizes in the centrosymmetric space group P, while compound 2 crystallizes in the noncentrosymmetric space group Pca2₁. Notably, compound 2 exhibits a moderate second harmonic generation (SHG) response of about 1.3 times that of KH₂PO₄ (KDP) under 1064 nm laser irradiation. Meanwhile, this compound displays green-yellow luminescence under 342 nm ultraviolet light irradiation, indicating its potential as a bifunctional optical material. Theoretical calculations based on density functional theory were also performed to gain insights into the correlation between their structures and optical properties.