Slow magnetic relaxation in one dimensional nitronyl nitroxide-Dy(III) chain suggesting single-chain magnet behavior

Two new nitronyl nitroxide bridged one-dimensional lanthanide complexes [Dy(hfac)3(NIT-2thien)]n (1); [Dy(hfac)3(NIT-3Brthien)]n (2) (hfac = hexafluoroacetylacetonate; NIT-2thien = 2-(2′-thienyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide; NIT-3Brthien = 2-(3′-bromo-2′-thienyl)-4,4,5,5- tetramethyl-imidazoline-1-oxyl-3-oxide) have been successfully prepared. Single crystal X-ray crystallographic analysis reveals that both complexes consist of linear chains built up by Dy(hfac)3 units bridged by nitronyl nitroxide radicals through their NO groups. AC measurements indicate that two complexes are out-of-phase frequency-dependent suggesting single-chain magnet behavior.