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

An organic–inorganic hybrid polyiodate, namely, [o‐C5H4NHOH]2[I7O18(OH)]⋅3 H2O (I), featuring a novel branched polyiodate chain has been obtained by evaporation method. [o‐C5H4NHOH]2[I7O18(OH)]⋅3 H2O (I) crystalizes in the polar space group Ia and features an [I7O18(OH)]∞2- branched polyiodate chain in which [I3O9]3− trimers are grafted on the same side of the one‐dimensional (1D) chain based on [I4O11(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×KH2PO4 (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. [ABSTRACT FROM AUTHOR]