Large mid-IR second-order nonlinear-optical effects designed by the supramolecular assembly of different bond types without IR absorption.

Two new different-bond-type hybrid compounds, (Hg6P4Cl3)(PbCl3) (1) and (Hg23P12)(ZnCl4)6 (2), with supramolecular interactions between host and guest moieties, which based on metal-pnicogen, pnicogen-pnicogen, and metal-halogen bonds were obtained by solid-state reactions. Compounds 1 and 2 show large second-harmonic-generation (SHG) activity and are transparent in the wide mid-IR region, providing an effective route for searching new IR nonlinear-optical material systems by combining two or more different bond types with no IR absorption within a single compound through supramolecular assembly. Theory predications based on first-principles calculations are also performed on the SHG properties of 1 and 2.