[<i>o</i>‐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-C₅ H₄ NHOH]₂ [I₇ O₁₈ (OH)]⋅3 H₂ O (I), featuring a novel branched polyiodate chain has been obtained by evaporation method. [o-C₅ H₄ NHOH]₂ [I₇ O₁₈ (OH)]⋅3 H₂ O (I) crystalizes in the polar space group Ia and features an [I₇ O₁₈ (OH)] <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mspace></mml:mspace> <mml:mrow><mml:mi>∞</mml:mi></mml:mrow> <mml:mrow><mml:mn>2</mml:mn> <mml:mo>-</mml:mo></mml:mrow> </mml:msubsup> </mml:math> branched polyiodate chain in which [I₃ O₉ ]^3- trimers are grafted on the same side of the one-dimensional (1D) chain based on [I₄ O₁₁ (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×KH₂ PO₄ (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.