Design of one-dimensional coordination networks from a macrocyclic {3d-4f} Single-Molecule Magnet precursor linked by [W(CN)8]3- anions

Abstract

The outcome of 1:1 reactions of the tetranuclear 3d-4f Single Molecule Magnet (SMM) [Cu3Tb(LPr)(NO3) 2(H2O)]NO3 (1) with (TBA)3[W(CN) 8] (TBA = tri-n-butyl ammonium cation, [(n-Bu)3N-H] +) in dimethylformamide (DMF) is dependent on the crystallization method employed: liquid-liquid diffusion of the reagents together gives {[Cu3Tb(LPr)W(CN)8(DMF)4] ·(DMF)}n (2) whereas diethyl ether vapor diffusion into the reaction solution gives {[Cu3Tb(LPr)W(CN) 8(DMF)3(H2O)3]·(DMF) 1.5·(H2O)0.5}n (3). Both compounds are obtained as black single crystals and feature one-dimensional (1D) coordination networks (chains) of [1]3+ macrocycles linked by [W(CN)8]3- anions. The two assemblies differ from a structural point of view. Complex 2 has a stepped arrangement with the linkers bound to the opposite faces of the macrocycle, whereas 3 has a square-wave arrangement due to the linkers binding to the same face of the macrocycle. Both compounds display an antiferromagnetic ground state below 3.5 and 2.4 K with a metamagnetic and antiferromagnetic (T, H) phase diagram for 2 and 3, respectively. Remarkably the slow dynamics of the magnetization of the [1] 3+ macrocycle units is preserved in 3 while this property is quenched in 2 because of stronger intra- and interchain magnetic interactions inducing a higher critical temperature. © 2013 American Chemical Society.