Exploration of SMM behavior of Ln complexes derived from thianaphthene-2-carboxylic acid.

Two lanthanide-based dinuclear complexes [Ln(L)(DMF)(HO)] (Ln = Dy (1)/Tb (2)) derived from thianaphthene-2-carboxylic acid have been synthesized and characterized in detail. Single-crystal XRD analyses confirm that the centro-symmetric discrete dimeric structures contain eight-coordinated lanthanide centers with biaugmented trigonal prism geometry in the complexes. Magnetic studies reveal the presence of antiferromagnetic interaction as well as thermal depopulation of Stark sublevels with a decrease in temperature for both complexes, whereas prominent field-induced single-molecule magnet behavior was observed for 1. Also, an isostructural yttrium-based complex (3) and a magnetically dilute sample of complex 1 (1') have been prepared for magnetic dilution study. 1' shows a combination of Orbach and Raman relaxation processes with effective energy barrier ΔE = 19.508 cm and relaxation time τ = 9.710 × 10 s.