A Switchable NLO Organic‐Inorganic Compound Based on Conformationally Chiral Disulfide Molecules and Bi(III)I₅ Iodobismuthate Networks

Abstract

International audience<p>A novel organic-inorganic hybrid based on cystamine and BiI5chains is prepared. Due to the flexibility of the disulfide molecules in the structure, single crystals or crystalline thin films of this hybrid undergo a reversible acentric-to-centric structural transition at moderate conditions (T = 36.8 °C). This makes the title compound an excellent candidate for temperature controlled SHG or THG switches.</p

Example of Disulfide Conformational Change in the Solid State: Preparation, Optical Properties, and X‐ray Studies of a Cystamine‐Based Iodoplombate Hybrid

“…This phenomenon was described as an exceptional conglomerate to true racemate reversible transition in the solid state. [4] More recently, a similar phenomenon, that is, a helical conformational change, was also observed in the parent bismuth compound leading to polymorphs α-and β-(H 2 cys)BiI 5 . [5] In both cases, hybrids, which are based on MI 5 chains of cornershared MI 6 octahedra, undergo a reversible acentric-to-centric structural transition, making them good candidates for SHG switches controlled by temperature.…”

“…[4] More recently, a similar phenomenon, that is, a helical conformational change, was also observed in the parent bismuth compound leading to polymorphs α-and β-(H 2 cys)BiI 5 . [5] In both cases, hybrids, which are based on MI 5 chains of cornershared MI 6 octahedra, undergo a reversible acentric-to-centric structural transition, making them good candidates for SHG switches controlled by temperature. In the broad field of nonlinear optic (NLO) materials, the incorporation of switchability into the NLO behavior is of high interest for applications in optoelectronic or photonic technologies.…”

“…[3] In the course of our investigations on perovskite-like compounds, we recently focused on the synthesis of halogenometalates of Bi III and Pb II hybrid materials containing the diprotonated cystamine molecule [H 3 N(CH 2 ) 2 S-S(CH 2 ) 2 NH 3 ] 2+ , here denoted by H 2 cys. [4][5][6] Although the conformational change in disulfides (leading to racemization) is well known in solution due to the relatively low barrier of rotation of S-S bonds (in the case of nonbulky R-and RЈ-organic groups), [7] we recently showed that the disulfide-based cystamine molecule was also able to change its conformation in the solid state. Thus, the α-[(H 2 cys)PbI 5 ·H 3 O] phase was transformed cal diprotonated cystamine cation in the solid state.…”

“…Although both structures are acentric, the intensity of the SHG signal of 1a is much higher than that of 1b. [5] whereas longer experiment times at 100°C favor the decomposition of cystamine as well as the formation of NH 4 I. The phase transition between 1a and 1b does not affect the crystalline quality, which allows us to perform a complete X-ray diffraction study by using one single crystal (data collected at 293 K and 323 K for 1a and 1b, respectively).…”

Experimental and theoretical studies of the second- and third-order NLO properties of a semi-organic compound: 6-Aminoquinolinium iodide monohydrate

“…For this reason the crystal engineering strategy of combining organic and inorganic moieties was proposed with the objective of building more cohesive crystalline structures [5]. Several examples of hybrid organic-inorganic crystals have emerged as good candidates for NLO materials [6,7,8,9]. These systems exhibit high nonlinear optical efficiency in the visible region and good thermal and mechanical stability compared with those of purely organic crystals.…”