Structure-directing and template roles of aromatic molecules in the self-assembly formation process of 3D holmium-succinate MOFs

Abstract

Two new holmium-succinate frameworks have been synthesized by hydrolysis in situ of the succinylsalicylic acid under different hydrothermal conditions. Compound 1, [Ho2(C4H4O4) 3(H2O)2]•0.33(C7H 6O3), Pī space group, has a novel structure composed by 1D-SBUs consisting of [HoO9] chains of polyhedra linked by the succinate ligands giving a 3D framework. Compound 2, [Ho2(C 4H4O4)3(H2O) 2], also belonging to the Pī space group, has a denser structure. The role of the in-situ-generated salicylic acid on formation of both structures is studied by means of a synthesis design methodology. A topological study of the new holmium succinate compounds in comparison with the previously reported 3D holmium-succinate framework is performed here.