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

Two organic-inorganic hybrid antimony(III) chlorides, namely (C 9 H 26 N 3 ) 2 Sb 4 Cl 18 (1) and (C 9 H 26 N 3 )SbCl 6 (2), were prepared using a facile solvent evaporation method. They have low-dimensional structures constructed from SbCl 6 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 1̄, while compound 2 crystallizes in the noncentrosymmetric space group Pca 2 1 . Notably, compound 2 exhibits a moderate second harmonic generation (SHG) response of about 1.3 times that of KH 2 PO 4 (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.