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.