Amino Acid Modification in One-Dimensional Cadmium Thiocyanates for Enhancing Second-Harmonic Generation Response

Colorless crystals of Cd(SCN)(l-C₃H₆NO₂) (1) and Cd(SCN)(l-C₅H₉N₂O₃)·H₂O (2) were grown under mild reaction environments. The two inorganic-organic hybrid compounds adopt one-dimensional structural motifs, wherein cadmium thiocyanate chains are interconnected by l-alanine and l-glutamine ligands, respectively. Both compounds feature wide optical bandgaps and sufficient birefringent values. Notably, compound 1 displays a second-harmonic generation (SHG) intensity of 0.5 × KH₂PO₄, whereas compound 2 exhibits a remarkably enhanced SHG response of 2.0 × KH₂PO₄.