Perfect layered arrangement of ion-paired chromophores in a crystalline non-linear optical organic salt: 2-amino-3-nitropyridinium chloride

Abstract

2-Amino-3-nitropyridinium chloride is reported as a new crystalline non-linear optical organic salt, built around a two-dimensional hyperpolarisable cationic chromophore. Its crystal structure (space groupP2 ₁ ) reveals a quasi-perfect layered arrangement of the cations and the anions. Within each layer the chromophores are arranged in a herringbone structure and strong hydrogen bonds are present. The first hyperpolarisabilities of ion-paired chromophores calculated for 2-amino-3-nitropyridinium chloride as well as 2-amino-5-nitropyridinium chloride emphasize the favourable contribution of the inorganic anionic sublattice to the enhancement of the molecular β _ijk and macroscopic χ ⁽²⁾ susceptibilities.