From centrosymmetric CN3H6C6H5SO3 to non-centrosymmetric CN3H6C6H4SO3(OH): Hydroxyl introduced hydrogen bond reconstruction to realize strong second harmonic generation

Non-centrosymmetric (NCS) crystalline structures, critical for second harmonic generation (SHG) in all-solid-state lasers, are far less prevalent than their centrosymmetric (CS) counterparts. In this study, we report a structural transformation from CS to NCS configuration in benzenesulfonate derivatives via hydroxyl group incorporation, as illustrated by the transition in the newly discovered CN 3 H 6 C 6 H 5 SO 3 (CS) and CN 3 H 6 C 6 H 4 SO 3 (OH) (NCS). The introduced hydroxyl groups induce hydrogen bond reconstruction, effectively breaking the original centrosymmetry. The resulting NCS compound exhibits remarkable nonlinear optical (NLO) properties, including a strong SHG response (1.6 × KDP with the particle sizes of 200–250 μm), a wide bandgap (UV cutoff at 290 nm, corresponding band gap is 4.37 eV), and a large birefringence (0.21@1064 nm), demonstrating excellent potential as an UV NLO crystal material.