Creation of MOFs with open metal sites by partial replacement of metal ions with different coordination numbers

Abstract

Herein, we developed isostructural metal–organic frameworks (MOFs) [Cu_1−xPd_x(SiF₆)(bpy)₂] (bpy: 4,4′-bipyridine) (SIFSIX-1-CuPd-3, -5 and -10) containing open metal sites using a partial metal-replacement approach. Starting from the SIFSIX-1-Cu-type MOF, some of the Cu²⁺ ions having octahedral geometry were successfully replaced with Pd²⁺ ions having square planar geometry in different ratios, while the framework structure was maintained. The results showed that gas adsorption properties of SIFSIX-1-Cu-type MOFs can be tuned via partial metal replacement.