[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)] 2À 1 branched polyiodate chain in which [I 3 O 9 ] 3À trimers are grafted on the same side of the one-dimensional (1D) chain based on [I 4 O 11 (OH)] 3À 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 À2 , 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.Second-harmonic-generation (SHG) materials harboring the capacity of generating coherent light are widely used in solid-state lasers in recently years. [1][2][3] The basic requirements for brilliant SHG materials include the NCS structures, strong SHG effects, high LIDT values, wide band gaps, phasematching capabilities, facile synthetic methods, etc. Metal iodates are a class of excellent SHG crystals due to the existence of the stereochemically active-lone-pair (SCALP) electrons of I 5+ cation which can undergo second-order Jahn-Teller (SOJT) distortion. [4,5] At present, several common strategies have been utilized to design new SHG iodates: (a) Introduction of SOJT distorted d 0 transitional metal (TM) cations (Mo 6+ , V 5+ , W 6+ , Nb 5+ , Ti 4+ , etc.). [6][7][8][9][10][11][12] The additive polarizations from both models of SOJT cations can result in strong SHG effects as exampled by A(VO) 2 O 2 (IO 3 ) 3 (A = K, Rb, Cs, NH 4 ) (500 SiO 2 and 3.6 KTiOPO 4 (KTP)); [7,8] (b) Introduction of cations with also SCALP electrons (Bi 3+ , Pb 2+ , etc.) as in BiO(IO 3 ) (12.5 KDP) and PbPt(IO 3 ) 6 (H 2 O) (8 KDP); [13,14] (c) Introduction of the strong electronegative F À anion which can widen the band gaps of iodates and

[C3N6H7]2[B3O3F4(OH)]: a new hybrid birefringent crystal with strong optical anisotropy induced by mixed functional units

“…For example, [C(NH 2 ) 3 ](H 2 C 3 N 3 O 3 ) ([C(NH 2 ) 3 ] + [H 2 C 3 N 3 O 3 ]), Sc(IO 3 ) 2 (NO 3 ) ([IO 3 ] + [NO 3 ]), [o-C 5 H 4 NHOH] 2 [I 7 O 18 (OH)]·3H 2 O ([o-C 5 H 4 NHOH] + [I 7 O 18 (OH)]), and K 12 Pb 51 (CN 2 ) 30 Cl 54 (Pb + [CN 2 ]) have been characterized as high-performing birefringent materials and they have all been designed by introducing different birefringence-active units. 11 Inspired by these, the assembly of the mixed functional modules [C 3 N 6 H 7 ] and [B 3 O 3 F 4 (OH)] led to the discovery of a new semi-organic fluorooxoborate with the formula [C 3 N 6 H 7 ] 2 [B 3 O 3 F 4 (OH)] (abbreviated as MelBF ). A combination of the large birefringence (0.440@546 nm) and short absorption edge (240 nm) makes MelBF a potential birefringent crystal applicable in the UV spectral region.…”

Explorations of New SHG Materials in Mercury Iodate Sulfate System**

“…[14] For example, [o-C 5 H 4 NHOH] 2 [I 7 O 18 (OH)] • 3H 2 O, which combines the non-centrosymmetric organic amine group with the branched [I 7 O 18 (OH)] 2À chain, produces a remarkable SHG signal of 8.5 × KDP at 1064 nm. [15] Introducing the most electronegative F element into metal iodates can generate crystals with novel structures. [16] [GaF(H 2 O)][IO 3 F] with [GaF(H 2 O)] 2 + chains and IO 3 F 2À polar groups exhibits a SHG effect of 10 × KDP at 1064 nm.…”

An Optically Anisotropic Crystal with Large Birefringence Arising from Cooperative π Orbitals

“…0.10@546 nm), [9a] ( o ‐C 5 H 4 NHOH) 2 [I 7 O 18 (OH)] ⋅ 3H 2 O (cal. 0.114@1064 nm), [9b] (C 5 H 6 ON)(H 2 PO 4 ) (cal. 0.25@1064 nm), [4g] CeF 2 (SO 4 ) (exp.…”