Breaking Symmetry for SHG Response: Lanthanide Acetate Crystals via Water Molecule Regulation Strategy

In the field of nonlinear optical (NLO) materials research, the design and synthesis of novel materials are crucial for advancing modern scientific and technological development. This study employs an innovative coordination strategy, building upon the existing structure of [Ln₂(CH₃COO)₆(H₂O)₄]·4H₂O (Ln = Tb, Sm), to successfully synthesize a series of acetate rare-earth metal compounds [Ln₂(CH₃COO)₆(H₂O)] [Ln = Tb(1), Er(2), Y(3)] by regulating the number of water molecules. This approach achieved a structural transition from centrosymmetric (CS) to noncentrosymmetric (NCS), endowing these compounds with significant nonlinear optical responses. We discovered that reducing the coordinated water molecules and introducing acetate as a bidentate ligand is an effective method for modulating crystal structure and realizing NLO performance. This finding not only deepens the understanding of the structure of acetate salts but also provides important theoretical and experimental support for the development of materials with potential NLO propeties.