Abstract
We report the synthesis, structures, and magnetic properties of a series of triangular Dy3 complexes with [Dy3(hmci)3(MeOH)6]·3MeOH·2MeCN·2H2O (1) and [Dy3(hmcb)3(MeOH)6]·3MeOH·1H2O (2) (H3hmci = 2-hydroxy-3-methoxy-5-iodobenzaldehyde hydrazone, H3hmcb = 2-hydroxy-3-methoxy-5-bromobenzaldehyde hydrazone). These complexes adopt a calixarene-like triangular topology with phenoxide-bridged Dy3+ ions, leading to near-perpendicular orientation of anisotropic axes relative to the Dy3 plane. Magnetic studies and theoretical calculations reveal rare examples of Ising spin frustration driven by dipolar interactions, while retaining a zero-field single-molecule-magnet (SMM) behavior. Furthermore, halogen substitutions at the para position of the ligands fine-tune the local crystal field environment, enabling modulation of the relaxation dynamics and slow magnetic relaxation profiles. These findings underscore the critical role of ligand design in tailoring spin frustration and optimizing the zero-field SMM performance of triangular Dy3 complexes.