Synthesis, Structural Characterization, and SHG Behavior of a Lanthanum/β-d-Fructose-Based Metal–Organic Framework

Interest in non-centrosymmetric crystalline materials exhibiting second harmonic generation (SHG) has increased due to their potential applications in optical sensing and biosensing. Saccharide-based metal complexes are particularly attractive systems, as chiral sugars can promote non-centrosymmetric crystal packing. In this work, a new lanthanum–β-D-fructose compound, [La(C6H12O6)(H2O)5]Cl3 (LaFRUCl), was synthesized using a simple and low-cost method and characterized by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic space group P212121 and consists of infinite (La3+–fructose)n chains extending along the [001] direction, forming a one-dimensional Metal–Organic Framework. The nonlinear optical response was evaluated using the Kurtz–Perry powder technique with a Nd:YAG laser (1064 nm) and compared to a sucrose reference. The measured SHG efficiency is comparable to that of previously reported alkaline earth metal–sugar analogs. While the compound’s SHG emission is significant, evaluation of its structural stability under aqueous or physiological conditions is be required before considering biological applications.