Systematic Tuning of the Magnetic Properties in Mixed-Metal MOF-74.

Recently, mixed-metal metal-organic frameworks (MOFs) have been attracting much attention in various fields. In this study, we have systematically investigated the magnetic properties of Co x Ni 1- x -MOF-74 [Co 2 x Ni 2(1- x ) (dhtp), where H 4 dhtp = 2,5-dihydroxyterephthalic acid] with two different kinds of metals (Co and Ni) across the composition range 0 ≤ x ≤ 1. Bimetallic Co x Ni 1- x -MOF-74 ( x = 0.752, 0.458, and 0.233) were successfully synthesized and confirmed to have homogeneous metal distributions. Weak ferromagnetic (canted antiferromagnetic) behavior was exhibited, while homometallic Co-MOF-74 and Ni-MOF-74 are antiferromagnetic. We also investigated the effects of C 2 H 4 sorption on the magnetic properties and found that C 2 H 4 -adsorbed Co 0.5 Ni 0.5 -MOF-74 exhibited a change in the interchain magnetic interaction.