Designing a 3‐Hydroxypropane‐1‐Sulfonate Deep‐Ultraviolet Nonlinear Optical Crystal

Abstract Although 3‐hydroxypropane‐1‐sulfonates are discovered several decades ago, their nonlinear optical (NLO) properties have remained unexplored, mainly because most of them crystallize in centrosymmetric space groups. Herein, by incorporating polarizable rare‐earth metal La ³⁺ cations, a novel non‐centrosymmetric 3‐hydroxypropane‐1‐sulfonate, namely La[SO ₃ (CH ₂ ) ₃ OH] ₃ is designed and synthesized, whose crystal structure features 3D framework constructed by highly distorted [LaO ₉ ] polyhedra and [SO ₃ (CH ₂ ) ₃ OH] ⁻ anions. Experimental results reveal that La[SO ₃ (CH ₂ ) ₃ OH] ₃ is NLO‐active with a moderate second‐harmonic generation response of 0.6 times that of the benchmark KH ₂ PO ₄ and a wide absorption edge below 190 nm. Structural analyses and first‐principles calculations reveal that the non‐centrosymmetric nature and NLO properties are closely related to highly polarizable cationic [LaO ₉ ] polyhedra. This work highlights 3‐hydroxypropane‐1‐sulfonates as promising candidates for deep‐ultraviolet NLO materials and provides some inspiration for designing non‐centrosymmetric structures.