Air-stable pentagonal-bipyramidal dysprosium(iii) single-molecule magnets with a sulfur-containing macrocyclic equatorial ligand

The fabrication of electronic devices utilizing single-molecule magnets (SMMs) requires deposition on conducting surfaces, which usually consist of thiophilic elements such as gold, silver and copper. Thus, SMMs possessing sulphur-containing ligands that are capable of attaching on such surfaces through chemical bonding are fascinating. Here, we designed and successfully isolated a series of pentagonal-bipyramidal dysprosium(iii) compounds with a sulfur-containing macrocycle PYNS ligand, [Dy(L_A)₂(PYNS)][BPh₄] (PYNS = 2,6-bis(4-(pyridin-2-yl)thiazol-2-yl)pyridine); L_A⁻ = ^tBuO⁻ for 1Dy; (S)-PhEtO⁻ for 2Dy; CF₃PhMeO⁻ for 3Dy; Ph₃SiO⁻ for 4Dy; (^tBuO)₃SiO⁻ for 5Dy). They exhibit zero-field SMM behaviour with effective energy barriers U_eff between 679 and 807 K, and the magnetic blocking temperatures T^IRREV_B for 3Dy and 5Dy were determined to be 2.5 K while, that of 4Dy is 3 K. The sulfur atoms at the peripheral position of PYNS are expected to act as linkers to adsorb the molecules onto gold surfaces.