[o‐C5H4NHOH]2[I7O18(OH)]⋅3 H2O: An Organic–Inorganic Hybrid SHG Material Featuring an [I7O18(OH)] Branched Polyiodate Chain

Abstract An organic–inorganic hybrid polyiodate, namely, [ o ‐C 5 H 4 NHOH] 2 [I 7 O 18 (OH)]⋅3 H 2 O ( I ), featuring a novel branched polyiodate chain has been obtained by evaporation method. [ o ‐C 5 H 4 NHOH] 2 [I 7 O 18 (OH)]⋅3 H 2 O ( I ) crystalizes in the polar space group Ia and features an [I 7 O 18 (OH)] branched polyiodate chain in which [I 3 O 9 ] 3− trimers are grafted on the same side of the one‐dimensional (1D) chain based on [I 4 O 11 (OH)] 3− tetramers. The asymmetric organic amine groups are beneficial to the polymerization of iodate groups and inducing the formation of the non‐centrosymmetric (NCS) structure. Compound I exhibits a rather large Second‐Harmonic‐ Generation (SHG) signal of 8.5×KH 2 PO 4 (KDP) upon 1064 nm laser radiation, a moderate band gap of 3.90 eV and a high laser‐induced‐damage‐threshold (LIDT) of 182.34 MW cm −2 , hence it is a promising new SHG material. The relationship between the structures of the organic amine groups and the overall structures has been also analyzed.