Synthesis and Properties of Highly Efficient Near-Infrared Luminescent Zn-Nd and Zn-Yb Multimetal Complexes

Abstract

Near-infrared (NIR) luminescent rare-earth complexes are highly sought-after for bioimaging and optical communication due to their distinctive optical characteristics. Herein, a series of Nd³⁺ and Yb³⁺ complexes were synthesized via a multistep protocol: first, forming an intermediate ligand–metal framework from appropriate precursors; then, coordinating with NdCl₃·6H₂O or YbCl₃·6H₂O; and finally, modifying with specific organic reagents. Their NIR luminescence properties were systematically investigated, revealing characteristic emission bands corresponding to the f-f electronic transitions of Nd³⁺ and Yb³⁺. The energy transfer processes within the complex structures and the influence of the ligand environment on emission intensity and lifetime were analyzed. These results offer insights into designing efficient rare-earth NIR luminescent materials, which show promise for NIR-based applications such as bioimaging and optical communication.